Title 24 · California Energy Code

What are the required wall U‑factors and insulation R‑values?

For prescriptive compliance, exterior walls must meet the assembly **U‑factor** limits (or — for mass walls — a continuous insulation **R‑value**) shown in **Table 150.1‑A**; the controlling rule is **§150.1(c)1**. The code checks the whole wall assembly (framing, cavity, continuous insulation and other layers) so you must either install the prescribed R or calculate the assembly U to verify it is equal to or lower than the Table limit.

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Last reviewed: July 6, 2026

What the code requires — plain English

The prescriptive rule is: framed exterior walls must meet a maximum assembly U‑factor shown in Table 150.1‑A, and mass walls may meet that same assembly U‑factor or meet a specified continuous insulation R‑value in Table 150.1‑A. See §150.1(c)1 for the requirement and the Table reference.

The building’s exterior walls must have an overall assembly thermal performance (U‑factor) at or below the limit in Table 150.1‑A — or, for mass walls, you may meet an equivalent continuous‑insulation R‑value instead.

Requirements in detail

Key definitions (first use)

  • U‑factor — the overall heat transfer coefficient of an assembly (lower is better). See §150.1(c)1.
  • R‑value — thermal resistance of insulation (higher is better). See §150.1(c)1.
  • Assembly U‑factor — the area‑weighted U of all elements in the wall (framing, cavity insulation, sheathing, continuous insulation, fenestration, etc.). The code allows use of Reference Joint Appendices (JA4) methods to develop equivalent assemblies.

Note: the controlling prescriptive table is Table 150.1‑A; it contains climate‑zone specific maximum assembly U‑factors and (for some conditions) continuous insulation R‑values. The text of §150.1(c)1 directs compliance to that table.

How the rule is applied (summary)

  • For framed exterior walls: design the wall so the assembly U‑factor is equal to or less than the value shown in Table 150.1‑A for your climate zone. You may achieve that with cavity insulation, continuous insulation, or a combination that yields an assembly U at or below the table value.
  • For mass walls (above or below grade): either meet the assembly U‑factor limit in Table 150.1‑A or install continuous insulation with the R‑value shown in Table 150.1‑A (the table specifies whether that R‑value is on the interior or exterior).
  • For other unframed exterior walls (not mass): follow the framed‑wall requirements in Table 150.1‑A.

Tradeoffs and calculation method

  • The code permits cavity-only, continuous-only, or combined insulation approaches as long as the assembly U‑factor is equal to or less than the table value. Use the Reference Joint Appendices (JA4) for alternative product equivalencies and U‑factor calculations.
  • The assembly U‑factor is area‑weighted. The code explicitly allows using an approved U‑factor calculation method as an alternative to simply installing the listed R‑values in the table (the executive director approval path).

Quality installation

  • When the prescriptive package in Table 150.1‑A requires Quality Insulation Installation (QII), the installation must be field‑verified per the Residential Reference Appendix RA3.5 procedures. Table 150.1‑A indicates where QII is required.

Decision‑relevant summary table

(Important: the uploaded files include §150.1(c)1 and the instructions that the limits are in Table 150.1‑A, but the numeric entries of Table 150.1‑A themselves were not captured in the provided files. See note below the table.)

Decision dimension What the code requires Code Reference
Framed exterior walls Assembly U‑factor ≤ the climate‑zone value in Table 150.1‑A (may be met by cavity, continuous, or combined insulation) §150.1(c)1
Mass walls (above & below grade) Assembly U‑factor ≤ Table 150.1‑A OR continuous insulation R‑value ≥ value in Table 150.1‑A (table notes whether interior or exterior) §150.1(c)1
Spandrel panels / curtain walls Minimum R‑4 or assembly U ≤ Table value (spandrels are treated separately in notes) See Table notes; §150.1(c)1
Raised floors / slab edges Floor assembly U ≤ or insulation R ≥ values shown in Table 150.1‑A (raised floors exception exists) §150.1(c)1
Quality Insulation Installation (QII) Field verification required where Table 150.1‑A indicates QII §150.1(c)1E and Table 150.1‑A

Note: The exact numeric U‑factor and R‑value entries per climate zone are contained in Table 150.1‑A. The text excerpts supplied include the controlling section language referencing that table but do not include the full numeric table contents; you must consult the official Table 150.1‑A (Title 24, Part 6) to get the per‑climate‑zone numbers.

Exceptions & special cases

  • The code allows using an approved U‑factor calculation method that considers thermal bridging and all assembly elements as an alternative to the table values; this alternative must be approved by the executive director. (Exception to §150.1(c)1.)
  • Raised floors: raised‑floor insulation can be omitted only if all conditions of the expressed exception are met (foundation walls insulated to Table 150.1‑A minimums, Class I or II vapor retarder over crawlspace floor, automatic vent louvers, and RA4.5.1 compliance). See §150.1(c)1 exception text.
  • Mass wall definition: mass walls are those with heat capacity ≥ 7.0 Btu/h‑ft²; mass‑wall treatment and continuous‑insulation R‑values are specifically noted in the table’s notes. Use the table and notes to determine whether your wall qualifies as “mass.”

Common mistakes

  • Assuming a cavity‑only R‑value equals compliance. The code checks assembly U‑factor, not just cavity R, because framing thermal bridging can raise the assembly U. Always compute or verify assembly U.
  • Forgetting to include continuous insulation, sheathing, plaster/finish layers, and framing fractions when calculating the assembly U. The Reference Joint Appendices (JA4) provide methods/products to convert R to U for assemblies — use them.
  • Not checking Table 150.1‑A for QII requirements. If QII is required and not performed/verified, the assembly may not comply.
  • Misclassifying a wall as “mass” (and using the mass‑wall R‑value instead of the framed‑wall U‑factor). Confirm mass‑wall heat capacity per the code notes.

Worked example — how to check a framed wall (process)

Important: I could not locate the numeric entries of Table 150.1‑A in the supplied files, so the example below shows the calculation steps and an illustrative numeric demonstration — replace the “Table limit” below with your climate‑zone value from the official Table 150.1‑A.

Scenario (illustrative): wood framed wall with 16" o.c. studs, cavity insulation R‑21 in the bays, and continuous exterior insulation R‑5. You want to know if the assembly meets the Table 150.1‑A U‑factor limit for your climate zone.

Steps:

  1. Determine component U‑values (examples/assumptions for demonstration only):

    • Cavity plus interior layers: approximate U_cavity ≈ 1 / 21 ≈ 0.0476 (Btu/h‑ft²‑°F).
    • Continuous exterior insulation R‑5 contributes U_ext ≈ 1 / 5 = 0.20 for the exterior face if the exterior were the only path — but continuous insulation reduces overall assembly heat flow; an exact assembly U requires a whole‑assembly calculation (see JA4).
    • Stud fraction: assume studs occupy 20% of the wall area with a stud U of roughly 0.20 (uninsulated wood stud path). The insulated bay area is 80%. (These numbers are illustrative; use actual framing fraction and material U from JA4.)

  2. Compute area‑weighted assembly U (simplified example):
    Assembly U ≈ (0.80 × U_cavity_with_ci) + (0.20 × U_stud_path)
    If the cavity + continuous insulation effective U for the bay is approximated as 0.04 (this is an illustrative simplification), then:
    Assembly U ≈ (0.80 × 0.04) + (0.20 × 0.20) = 0.032 + 0.040 = 0.072 Btu/h‑ft²‑°F

  3. Compare to Table 150.1‑A limit:

    • If your climate‑zone limit (from Table 150.1‑A) is, for example, U ≤ 0.080, then Assembly U = 0.072 passes.
    • If the limit is U ≤ 0.060, the assembly fails and you must add more continuous insulation, increase cavity R, or reduce framing fraction.

  4. Notes on accuracy: use Reference JA4 methods or software to get accurate assembly U (the code explicitly points to JA4 tables for alternate product/assembly equivalencies). Do not rely on the simplified arithmetic above for final compliance documentation.

Related provisions

  • §150.1(c)9 — Roof/ceiling insulation options and attic/roof trade‑offs referenced by the prescriptive package.
  • §150.1(c)1E — Quality Insulation Installation (QII) requirements and where QII is required in Table 150.1‑A.
  • Reference Joint Appendices JA4 — methods and tables for converting R‑values and component properties to assembly U‑factors (see JA4 Table references in the code).
  • §150.0(c) — separate residential wall U‑factor/R‑value rules (note: similar language appears elsewhere; always use the prescriptive package Table 150.1‑A for the prescriptive compliance path called out by §150.1(c)).

If you want, I can:

  • Extract the numeric entries from Table 150.1‑A for your climate zone and build a short checklist showing exact U and R targets; or
  • Run a JA4‑based assembly U‑factor calculation for a proposed assembly (you’d provide layer‑by‑layer materials, dimensions, framing fraction, and climate zone).

Code references

Grounded in the retrieved California Energy Code — click a citation to read the verbatim passage:

  • § 0.110. High relevance — show source text

    C. Wood framed and others. A minimum of R-11 insulation between framing members, or the area-weighted average U- factor of the wall assembly shall not exceed U-0.110. D. Spandrel panels and curtain walls. A minimum of R-4, or the area-weighted average U- factor of the wall assembly shall not exceed U-0.280.

    Exception to Section 180.2(a)2: Light and heavy mass walls. 3. Floor insulation. For the altered portion of raised floors that separate conditioned spaces from unconditioned spaces or ambient air shall meet the applicable requirements of Items A and B below: A. Raised framed floors. A minimum of R-11 insulation between framing members, or the area-weighted average U- factor of the floor assembly shall not exceed U-0.071. B. Raised mass floors. A minimum of R-6 insulation, or the area-weighted average U- factor of the floor assembly shall not exceed U-0.111.

    (b) Prescriptive approach. The altered component and any newly installed equipment serving the alteration shall meet the applicable requirements of Sections 110.0 through 110.9 and all applicable requirements of Sections 160.0, 160.1, 160.2(c) and (d), 160.3(a) through 160.3(b)5J, 160.3(b)6, 160.3(c) and 160.5; and

    2025 CALIFORNIA ENERGY CODE 273

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    MULTIFAMILY BUILDINGS—ADDITIONS, ALTERATIONS AND REPAIRS TO EXISTING MULTIFAMILY BUILDINGS

    1. Envelope. A. Roof alterations . Existing roofs being replaced, recovered or recoated of a multifamily building shall meet the requirements of Section 110.8(i). For roofs with more than 50 percent of the roof area or more than 2,000 square feet of roof, whichever is less, being altered, the requirements of i through iii below apply: i. Low-sloped roofs in Climate Zones 2, 4, and 6 through 15 shall have a minimum aged solar reflectance of 0.63 and a minimum thermal emittance of 0.75, or a minimum SRI of 75. Exception to Section 180.2(b)1Ai: The aged solar reflectance requirement can be met by using insulation at the roof deck specified in Table 180.2-A.
    TABLE 180.2-A—ROOF/CEILING INSULATION TRADEOFF FOR LOW-SLOPED AGED SOLAR REFLECTANCE Col2 Col3
    MINIMUM
    AGED SOLAR REFLECTANCE    		 ROOF DECK CONTINUOUS INSULATIONR-
    VALUE (Climate Zones 6–7)    		 ROOF DECK CONTINUOUS INSULATION_R-_VALUE
    (Climate Zones 2, 4, 8–15)
    0.60 2 16
    0.55 4 18
    0.50 6 20
    0.45 8 22
    No requirement 10 24

    ii. Steep-sloped roofs in Climate Zones 4 and 8 through 15 shall have a minimum aged solar reflectance of 0.20 and a minimum thermal emittance of 0.75, or a minimum SRI of 16.

  • § 150.1 High relevance — show source text

    1(c)9A|NA|NA|NA|NA|NA|NA|NA|NA|NA|NA|NA|NA|NA|NA|NA|NA| |Option C14
    Roof/Ceiling - Duct Insulation|R-6|R-6|R-6|R-6|R-6|R-6|R-6|R-6|R-6|R-6|R-6|R-6|R-6|R-6|R-6|R-6| |Option C    11, 14     - §150.1(c)9B|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ| |FID required if HRV/ERV Systems
    Installed|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ| |Water Heating -150.1(c)8|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ|REQ| |1. Install the specified_R_-value with an air space present between the roofing and the roof deck, such as standard installation of concrete or clay tile.
    2._ R_-values shown for below roof deck insulation are for wood-framed construction with insulation installed between the framing members. Alternatives including insulation
    above rafters or above roof deck shall comply with the performance standards.
    3. Assembly_U_-factors for exterior framed walls can be met with cavity insulation alone or with continuous insulation alone, or with both cavity and continuous insulation that
    results in an assembly_U_-factor equal to or less than the_U_-factor shown. Use Reference Joint Appendices JA4 Table 4.3.1, 4.3.1(a), or Table 4.3.4 to determine alternative insu-
    lation products to be less than or equal to the required maximum_U_-factor.
    4. Assembly_U_-factors for roofs can be met with cavity insulation alone or with continuous insulation alone, or with both cavity and continuous insulation that results in an
    assembly_U_-factor equal to or less than the_U_-factor shown. Use Reference Joint Appendices JA4 Table 4.2.2 to determine alternative insulation products to be less than or
    equal to the required maximum_U_-factor.R-values shown represent the required insulation to meet the maximum_U_-factor with cavity insulation alone.
    5. Mass wall has a heat capacity greater than or equal to 7.0 Btu/h-ft2.
    6. “Interior” denotes insulation installed on the inside surface of the wall. “Exterior” denotes insulation installed on the exterior surface of the wall.
    7. Below grade “interior” denotes insulation installed on the inside surface of the wall, and below grade “exterior” denotes insulation installed on the outside surface of the wall.
    8. HSPF2 means heating seasonal performance factor.
    9. When whole-house fans are required (REQ), only those whole-house fans that are listed in the Home Ventilating Institute Certified Products Directory may be installed.
    Compliance requires installation of one or more WHFs whose total airflow cfm is capable of meeting or exceeding a minimum 1.5 cfm/square foot of conditioned floor area as
    specified by Section 150.1(c)12.
    10.

  • § 0.30 High relevance — show source text

    28|0.30|0.28|0.28|0.28|0.28| |All Other Fenestration -
    Maximum RSHGC|NR|0.23|NR|0.23|NR|0.23|0.23|0.23|0.23|0.23|0.23|0.23|0.23|0.23|0.23|NR| |Maximum Window to Floor
    Ratio|20%|20%|20%|20%|20%|20%|20%|20%|20%|20%|20%|20%|20%|20%|20%|20%| |Maximum Window to Wall
    Ratio|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%| |Maximum Skylight Roof Ratio|5%|5%|5%|5%|5%|5%|5%|5%|5%|5%|5%|5%|5%|5%|5%|5%| |1. Install the specified_R_-value with an airspace present between the roofing and the roof deck. Such as standard installation of concrete or clay tile.
    2._ R_-values shown for below roof deck insulation are for wood-frame construction with insulation installed between the framing members. Alternatives including insulation
    above rafters or above roof deck shall comply with the performance standards.
    3. Assembly_U_-factors for exterior framed walls can be met with cavity insulation alone or with continuous insulation alone, or with both cavity and continuous insulation that
    results in an assembly_U_-factor equal to or less than the_U_-factor shown. Use Reference Joint Appendices JA4 Table 4.3.1, 4.3.1(a), or Table 4.3.4 to determine alternative insu-
    lation products to be less than or equal to the required maximum U-factor.
    4. Mass wall has a heat capacity greater than or equal to 7.0 Btu/h-ft2.
    5. Product must be certified to meet the North American Fenestration Standard/Specification for an Architectural Window (AW).
    6. Glazed doors must meet the fenestration requirements.
    7. Requirements apply to doors included in the curtain wall/storefront construction assembly.
    8. If using_F_-factor to comply, use Reference Joint Appendices JA4, Table 4.4.7 to determine alternate depth and R-value to be less than or equal to the required maximum_F_-
    factor.
    9. Option B meets §170.2(a)1Bii.
    10. Option C meets §170.2(a)1BIiii.
    11. Option D meets §170.2(a)1Biv.|1. Install the specified_R_-value with an airspace present between the roofing and the roof deck. Such as standard installation of concrete or clay tile.
    2._ R_-values shown for below roof deck insulation are for wood-frame construction with insulation installed between the framing members. Alternatives including insulation
    above rafters or above roof deck shall comply with the performance standards.
    3. Assembly_U_-factors for exterior framed walls can be met with cavity insulation alone or with continuous insulation alone, or with both cavity and continuous insulation that
    results in an assembly_U_-factor equal to or less than the_U_-factor shown.

  • § 4.3.1 High relevance — show source text

    Use Reference Joint Appendices JA4 Table 4.3.1, 4.3.1(a), or Table 4.3.4 to determine alternative insu-
    lation products to be less than or equal to the required maximum U-factor.
    4. Mass wall has a heat capacity greater than or equal to 7.0 Btu/h-ft2.
    5. Product must be certified to meet the North American Fenestration Standard/Specification for an Architectural Window (AW).
    6. Glazed doors must meet the fenestration requirements.
    7. Requirements apply to doors included in the curtain wall/storefront construction assembly.
    8. If using_F_-factor to comply, use Reference Joint Appendices JA4, Table 4.4.7 to determine alternate depth and R-value to be less than or equal to the required maximum_F_-
    factor.
    9. Option B meets §170.2(a)1Bii.
    10. Option C meets §170.2(a)1BIiii.
    11. Option D meets §170.2(a)1Biv.|1. Install the specified_R_-value with an airspace present between the roofing and the roof deck. Such as standard installation of concrete or clay tile.
    2._ R_-values shown for below roof deck insulation are for wood-frame construction with insulation installed between the framing members. Alternatives including insulation
    above rafters or above roof deck shall comply with the performance standards.
    3. Assembly_U_-factors for exterior framed walls can be met with cavity insulation alone or with continuous insulation alone, or with both cavity and continuous insulation that
    results in an assembly_U_-factor equal to or less than the_U_-factor shown. Use Reference Joint Appendices JA4 Table 4.3.1, 4.3.1(a), or Table 4.3.4 to determine alternative insu-
    lation products to be less than or equal to the required maximum U-factor.
    4. Mass wall has a heat capacity greater than or equal to 7.0 Btu/h-ft2.
    5. Product must be certified to meet the North American Fenestration Standard/Specification for an Architectural Window (AW).
    6. Glazed doors must meet the fenestration requirements.
    7. Requirements apply to doors included in the curtain wall/storefront construction assembly.
    8. If using_F_-factor to comply, use Reference Joint Appendices JA4, Table 4.4.7 to determine alternate depth and R-value to be less than or equal to the required maximum_F_-
    factor.
    9. Option B meets §170.2(a)1Bii.
    10. Option C meets §170.2(a)1BIiii.
    11. Option D meets §170.2(a)1Biv.|1. Install the specified_R_-value with an airspace present between the roofing and the roof deck. Such as standard installation of concrete or clay tile.
    2._ R_-values shown for below roof deck insulation are for wood-frame construction with insulation installed between the framing members. Alternatives including insulation
    above rafters or above roof deck shall comply with the performance standards.
    3. Assembly_U_-factors for exterior framed walls can be met with cavity insulation alone or with continuous insulation alone, or with both cavity and continuous insulation that
    results in an assembly_U_-factor equal to or less than the_U_-factor shown.

  • § 0.037. High relevance — show source text

    In wood framed assemblies, compliance with U -factors may be demonstrated by installing wall insulation with an R -value of R-15 in 2x4 assemblies, and R-21 in 2x6 assemblies with 16 inches on center spacing.

    (d) Raised-floor insulation. Raised floors separating conditioned space from unconditioned space or ambient air shall have an overall assembly U -factor not exceeding U-0.037. In a wood framed assembly, compliance with the U -factor may be demonstrated by installing insulation with an R -value of 19 or greater.

    Exception to Section 150.0(d): A building with a controlled ventilation or unvented crawlspace may omit raised floor insulation if all of the following are met: i. The foundation walls are insulated to meet the wall insulation minimums as shown in Table 150.1-A; and

    ii. A Class I or Class II vapor retarder is placed over the entire floor of the crawl space; and iii. Vents between the crawlspace and outside air are fitted with automatically operated louvers that are temperature actuated; and

    2025 CALIFORNIA ENERGY CODE 159

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    SINGLE-FAMILY RESIDENTIAL BUILDINGS— MANDATORY FEATURES AND DEVICES

    iv. The requirements in Reference Residential Appendix RA4.5.1.

    (e) Installation of fireplaces, decorative gas appliances and gas logs. If a masonry or factory-built fireplace is installed, it shall comply with Section 110.5, Section 4.503 of Part 11, and shall have the following:

    1. Closable metal or glass doors covering the entire opening of the firebox; and
    2. A combustion air intake to draw air from the outside of the building, which is at least 6 square inches in area and is equipped with a readily accessible, operable and tight-fitting damper or combustion-air control device; and Exception to Section 150.0(e)2: An outside combustion-air intake is not required if the fireplace will be installed over concrete slab flooring and the fireplace will not be located on an exterior wall.
    3. A flue damper with a readily accessible control. Exception to Section 150.0(e)3: When a gas log, log lighter or decorative gas appliance is installed in a fireplace, the flue damper shall be blocked open if required by the CMC or the manufacturer’s installation instructions.

    (f) Slab edge insulation. Material used for slab edge insulation shall meet the following minimum specifications:

    1. Water absorption rate for the insulation material alone without facings no greater than 0.3 percent when tested in accordance with Test Method A – 24-Hour-Immersion of ASTM C272.

    2. Water vapor permeance no greater than 2.0 perm/inch when tested in accordance with ASTM E96.

    3. Concrete slab perimeter insulation shall be protected from physical damage and ultraviolet light deterioration.

    4. Insulation for a heated slab floor shall meet the requirements of Section 110.8(g).

    (g) Vapor retarder.

    1. In Climate Zones 1–16, the earth floor of unvented crawl space shall be covered with a Class I or Class II vapor retarder. This requirement shall also apply to controlled ventilation crawl space for buildings complying with the Exception to Section 150.0(d).
  • § 141.0 High relevance — show source text

    Exception 2 to Section 141.0(a): Where an existing system with electric reheat is expanded by adding variable air volume (VAV) boxes to serve an addition, total electric reheat capacity may be expanded so that the total capacity does not exceed 150 percent of the existing installed electric heating capacity in any one permit, and the system need not comply with Section 140.4(g). Additional electric reheat capacity in excess of 150 percent of the existing installed electric heating capacity may be added subject to the requirements of Section 140.4(g).

    Exception 3 to Section 141.0(a): Duct sealing. When ducts are extended from an existing duct system to serve the addition, the existing duct system and the extended ducts shall meet the applicable requirements specified in Section 141.0(b)2D.

    Exception 4 to Section 141.0(a): Additions that increase the area of the roof by 2,000 square feet or less are not required to comply with Section 110.10.

    Exception 5 to Section 141.0(a): A gas hot water boiler system with a total system input of at least 1 MMBtu/h but no more than 10 MMBtu/h added to an existing building is not required to comply with Section 140.4(k)8.

    Exception 6 to Section 141.0(a): A gas service water-heating system with a total system input of at least 1 MMBtu/h added to an existing building is not required to comply with Section 140.5(c).

    Exception 7 to Section 141.0(a) : Section 140.4(a)2 shall not apply to new space-conditioning systems or components.

    2025 CALIFORNIA ENERGY CODE 149

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    NONRESIDENTIAL AND HOTEL/MOTEL OCCUPANCIES— ADDITIONS, ALTERATIONS AND REPAIRS

    (b) Alterations. Alterations to components of existing nonresidential, hotel/motel, or relocatable public school buildings, including alterations made in conjunction with a change in building occupancy to a nonresidential, high-rise residential or hotel/motel occupancy shall meet Item 1, and either Item 2 or 3 below:

    1. Mandatory requirements. Altered components in a nonresidential or hotel/motel building shall meet the minimum requirements in this section. A. Roof/ceiling insulation. The opaque portions of the roof/ceiling that separate conditioned spaces from unconditioned spaces or ambient air shall meet the requirements of Section 141.0(b)2Bii. B. Wall insulation. For the altered opaque portion of walls separating conditioned spaces from unconditioned spaces or ambient air shall meet the applicable requirements of Items 1 through 4 below:
    2. Metal building. A minimum of R-13 insulation between framing members, or the area-weighted average U factor of the wall assembly shall not exceed U-0.113.
    3. Metal framed. A minimum of R-13 insulation between framing members, or the area-weighted average U- factor of the wall assembly shall not exceed U-0.217.
    4. Wood framed and others. A minimum of R-11 insulation between framing members, or the area-weighted average U -factor of the wall assembly shall not exceed U-0.110.
    5. **Spandrel panels and glass curtain walls.
  • § 150.1 High relevance — show source text

    viii. Building enclosure air leakage. When performance compliance requires a building enclosure leakage rate that is lower than the standard design, the building enclosure shall be field verified in accordance with the procedures specified in Reference Residential Appendix RA3.8. ix. Quality Insulation Installation (QII). When performance compliance requires field verification of QII, the building insulation system shall be field verified in accordance with the procedures in Reference Residential Appendix RA3.5.

    (c) Prescriptive standards/component packages. Buildings that comply with the prescriptive standards shall be designed, constructed and equipped to meet all of the requirements for the appropriate climate zone shown in Table 150.1-A. In Table 150.1-A, an NA (not allowed) means that feature is not permitted in a particular climate zone and an NR (no requirement) means that there is no prescriptive requirement for that feature in a particular climate zone. Installed components shall meet the following requirements:

    1. Insulation.

    A. Roof and ceiling insulation shall be installed with an R -value equal to or greater than that shown in Table 150.1-A meeting Option i, ii or iii below. i. Option A: Reserved. ii. Option B: A minimum R -value of insulation in a ventilated attic installed between the roof rafters in contact with the roof deck and an additional layer of ceiling insulation located between the attic and the conditioned space when meeting Section 150.1(c)9A; or iii. Option C: A minimum R -value of ceiling insulation located between a ventilated attic and the conditioned space or within a cathedral ceiling assembly shall comply with Section 150.1(c)9B.

    B. Walls.

    i. Framed exterior walls shall be insulated such that the exterior wall has an assembly U -factor equal to or less than that shown in Table 150.1-A. The U -factors shown are maximum U -factors for the exterior wall assembly. ii. Mass walls above grade and below grade shall be insulated such that the wall has an assembly U -factor equal to or less than that shown in Table 150.1-A, or walls shall be insulated with continuous insulation that has an R value equal to or greater than that shown in Table 150.1-A. “Interior” denotes continuous insulation installed on the inside surface of the wall, and “exterior” denotes continuous insulation installed on the outside surface of the wall.

    iii. Other unframed exterior walls, excluding mass walls, shall meet the requirements for framed walls shown in Table 150.1-A.

    C. Raised floors shall be insulated such that the floor assembly has an assembly U -factor equal to or less than shown in Table 150.1-A, or shall be insulated between wood framing with insulation having an R- value equal to or greater than that shown in Table 150.1-A.

    Exception to Section 150.1(c)1C: Raised-floor insulation may be omitted if the foundation walls are insulated to meet the wall insulation minimums shown in Table 150.1-A, and a vapor retarder is placed over the entire floor of the crawl space, and the vents are fitted with automatically operated louvers, and the requirements of Reference Residential Appendix RA4.5.1 are met. D. Slab floor perimeter insulation shall be installed with a U -factor equal to or less than, or R -value equal to or greater than, shown in Table 150.1-A.

  • § 150.1 High relevance — show source text

    i. Framed exterior walls shall be insulated such that the exterior wall has an assembly U -factor equal to or less than that shown in Table 150.1-A. The U -factors shown are maximum U -factors for the exterior wall assembly. ii. Mass walls above grade and below grade shall be insulated such that the wall has an assembly U -factor equal to or less than that shown in Table 150.1-A, or walls shall be insulated with continuous insulation that has an R value equal to or greater than that shown in Table 150.1-A. “Interior” denotes continuous insulation installed on the inside surface of the wall, and “exterior” denotes continuous insulation installed on the outside surface of the wall.

    iii. Other unframed exterior walls, excluding mass walls, shall meet the requirements for framed walls shown in Table 150.1-A.

    C. Raised floors shall be insulated such that the floor assembly has an assembly U -factor equal to or less than shown in Table 150.1-A, or shall be insulated between wood framing with insulation having an R- value equal to or greater than that shown in Table 150.1-A.

    Exception to Section 150.1(c)1C: Raised-floor insulation may be omitted if the foundation walls are insulated to meet the wall insulation minimums shown in Table 150.1-A, and a vapor retarder is placed over the entire floor of the crawl space, and the vents are fitted with automatically operated louvers, and the requirements of Reference Residential Appendix RA4.5.1 are met. D. Slab floor perimeter insulation shall be installed with a U -factor equal to or less than, or R -value equal to or greater than, shown in Table 150.1-A. The minimum depth of concrete-slab floor perimeter insulation shall be 16 inches or the depth of the footing of the building, whichever is less. Exception to Section 150.1(c)1: The insulation requirements of Table 150.1-A may also be met by ceiling, roof deck, wall, or floor assemblies that meet the required maximum U -factors using a U -factor calculation method that considers the thermal effects of all elements of the assembly and is approved by the executive director. E. All buildings shall comply with the quality insulation installation (QII) requirements shown in Table 150.1-A. When QII is required, insulation installation shall meet the criteria specified in Reference Appendix RA3.5.

    178 2025 CALIFORNIA ENERGY CODE

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    SINGLE-FAMILY RESIDENTIAL BUILDINGS—PERFORMANCE AND PRESCRIPTIVE COMPLIANCE APPROACHES

    1. Radiant barrier. A radiant barrier required in Table 150.1-A shall meet the requirements specified in Section 110.8(j) and shall meet the installation criteria specified in the Reference Residential Appendix RA4.

    2. Fenestration.

    A. Installed fenestration products, including glazed doors, shall have an area weighted average U -factor and Solar Heat Gain Coefficient (SHGC) meeting the applicable fenestration value in Table 150.1-A and shall be determined in accordance with Sections 110.6(a)2 and 110.6(a)3. Exception 1 to Section 150.1(c)3A: New dwelling units with a conditioned floor area of 500 square feet or less in Climate Zone 5 may comply with a maximum U -factor of 0.30.

  • § 141.0 High relevance — show source text

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    NONRESIDENTIAL AND HOTEL/MOTEL OCCUPANCIES— ADDITIONS, ALTERATIONS AND REPAIRS

    (b) Alterations. Alterations to components of existing nonresidential, hotel/motel, or relocatable public school buildings, including alterations made in conjunction with a change in building occupancy to a nonresidential, high-rise residential or hotel/motel occupancy shall meet Item 1, and either Item 2 or 3 below:

    1. Mandatory requirements. Altered components in a nonresidential or hotel/motel building shall meet the minimum requirements in this section. A. Roof/ceiling insulation. The opaque portions of the roof/ceiling that separate conditioned spaces from unconditioned spaces or ambient air shall meet the requirements of Section 141.0(b)2Bii. B. Wall insulation. For the altered opaque portion of walls separating conditioned spaces from unconditioned spaces or ambient air shall meet the applicable requirements of Items 1 through 4 below:
    2. Metal building. A minimum of R-13 insulation between framing members, or the area-weighted average U factor of the wall assembly shall not exceed U-0.113.
    3. Metal framed. A minimum of R-13 insulation between framing members, or the area-weighted average U- factor of the wall assembly shall not exceed U-0.217.
    4. Wood framed and others. A minimum of R-11 insulation between framing members, or the area-weighted average U -factor of the wall assembly shall not exceed U-0.110.
    5. Spandrel panels and glass curtain walls. A minimum of R-4, or the area-weighted average U -factor of the wall assembly shall not exceed U-0.280. Exception to Section 141.0(b)1B: Light and heavy mass walls. C. Floor insulation. For the altered portion of raised floors that separate conditioned spaces from unconditioned spaces or ambient air shall meet the applicable requirements of Items 1 through 3 below:
    6. Raised framed floors. A minimum of R-11 insulation between framing members, or the area-weighted average U -factor of the floor assembly shall not exceed the U -factor of U-0.071.
    7. Raised mass floors in hotel/motel guest rooms. A minimum of R-6 insulation, or the area-weighted average U -factor of the floor assembly shall not exceed the U -factor of U-0.111.
    8. Raised mass floors in other occupancies. No minimum U -factor requirement. D . Fan energy index: New fan systems serving an existing building shall meet the requirements of Section 120.10. E. Exterior windows. Fenestration alterations other than repairs shall meet the following requirements:
    9. Vertical fenestration alterations. Where over 150 square feet of the entire building’s vertical fenestration is replaced, the maximum U -factor of the replaced units shall not exceed U-0.58.
    10. Added vertical fenestration. Where over 50 square feet of vertical fenestration is added, it shall meet the requirements of Section 120.7(d). Where 50 square feet or less of vertical fenestration is added, this requirement shall not apply.
    11. **Prescriptive approach.
  • § 203.1.1 High relevance — show source text

    A4.203.1.1 Long-term system cost (LSC). LSC rating for the building’s Proposed Design shall be computed by Compliance Software certified by the Energy Commission as specified in Title 24, Part 6, Section 100.1 and 150.1(b), and shall reduce the LSC required in the Compliance Software for minimum performance-based compliance with the California Energy Code by the compliance margin specified in Table A4.203.1.1. The rating shall be included in the Certificate of Compliance documentation.

    TABLE A4.203.1.1—RECOMMENDED LSC MARGINS BY CLIMATE ZONES Col2
    CALIFORNIA ENERGY CODE CLIMATE ZONE TOTAL LSC COMPLIANCE MARGIN
    1 2.70
    2 1.62
    3 1.10
    4 1.11
    5 1.01
    6 0.24
    7 0.24
    8 0.21
    9 0.20
    10 0.18
    11 1.11
    12 1.05
    13 0.96
    14 1.21
    15 0.59
    16 1.68
    Note: Community shared options complying with Title 24, Part 1, Section 10-115 may be used to achieve LSC targets. Note: Community shared options complying with Title 24, Part 1, Section 10-115 may be used to achieve LSC targets.

    2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-9

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

    A4.203.1.2 Prerequisite options. In addition, a minimum of TWO of the efficiency measures specified in Sections A4.203.1.2.1 through A4.203.1.2.7 must be met.

    A4.203.1.2.1 Roof deck insulation, or ducts in conditioned space. Meet one of the three options for the location of ducts and air handlers as well as insulation R -values and installation of a radiant barrier as specified in Title 24, Part 6, Section 150.1(c)9A or B:

    1. Below roof deck insulation with a minimum R -value of 19; or,

    2. Continuous above deck insulation with a minimum R-8 and with an air space present between the roofing and the roof deck; or,

    3. All ducts and air handlers in conditioned space as specified in the Title 24, Part 6, Reference Appendix RA3.1.

    A4.203.1.2.2 High performance walls. Meet the climate zone dependent U -factor or insulation R -value for either 2x6 or 2x4 framing as specified in Title 24, Part 6, Section 150.1(c)1B: maximum U -factor of 0.048.

    A4.203.1.2.3 Compact hot water distribution system. Meet the requirements for installation of Compact Hot Water Distribution Systems specified in the Title 24, Part 6, Reference Appendix RA3.6.5.

  • § 110.7 High relevance — show source text
    1. Attic access doors shall have permanently attached insulation using adhesive or mechanical fasteners. The attic access shall be gasketed to prevent air leakage; and
    2. Insulation shall be installed in direct contact with a roof or ceiling which is sealed to limit infiltration and exfiltration as specified in Section 110.7, including but not limited to placing insulation either above or below the roof deck or on top of a drywall ceiling.

    (b) Loose-fill insulation. When loose-fill insulation is installed, the minimum installed weight per square foot shall conform with the insulation manufacturer’s installed design weight per square foot at the manufacturer’s labeled R -value.

    (c) Wall insulation. Opaque portions of above grade walls separating conditioned spaces from unconditioned spaces or ambient air shall meet the following requirements:

    1. 2 × 4 inch framing shall have an overall assembly U -factor not exceeding U-0.095 Exception to Section 150.0(c)1: Existing walls already insulated to a U -factor not exceeding U-0.110 or already insulated between framing members with insulation having an installed thermal resistance of R-11 or greater.
    2. 2 × 6 inch or greater framing shall have an overall assembly U -factor not exceeding U-0.069.
    3. Opaque nonframed assemblies shall have an overall assembly U -factor not exceeding U-0.102.
    4. Bay or bow window roofs and floors shall be insulated to meet the wall insulation requirements of Table 150.1-A.
    5. Masonry/mass walls shall be insulated to meet the wall insulation requirements of Table 150.1-A.
    6. In wood framed assemblies, compliance with U -factors may be demonstrated by installing wall insulation with an R -value of R-15 in 2x4 assemblies, and R-21 in 2x6 assemblies with 16 inches on center spacing.

    (d) Raised-floor insulation. Raised floors separating conditioned space from unconditioned space or ambient air shall have an overall assembly U -factor not exceeding U-0.037. In a wood framed assembly, compliance with the U -factor may be demonstrated by installing insulation with an R -value of 19 or greater.

    Exception to Section 150.0(d): A building with a controlled ventilation or unvented crawlspace may omit raised floor insulation if all of the following are met: i. The foundation walls are insulated to meet the wall insulation minimums as shown in Table 150.1-A; and

    ii. A Class I or Class II vapor retarder is placed over the entire floor of the crawl space; and iii. Vents between the crawlspace and outside air are fitted with automatically operated louvers that are temperature actuated; and

    2025 CALIFORNIA ENERGY CODE 159

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    SINGLE-FAMILY RESIDENTIAL BUILDINGS— MANDATORY FEATURES AND DEVICES

    iv. The requirements in Reference Residential Appendix RA4.5.1.

    (e) Installation of fireplaces, decorative gas appliances and gas logs. If a masonry or factory-built fireplace is installed, it shall comply with Section 110.5, Section 4.503 of Part 11, and shall have the following:

    1. Closable metal or glass doors covering the entire opening of the firebox; and
  • § 3.2 High relevance — show source text

    Insulation requirements are for protection against frost damage in heated buildings. Greater values could be required to meet energy conservation standards.
    b. See Figure R403.3(2) or Table R403.3(2) for Air-Freezing Index values.
    c. Insulation materials shall provide the stated minimum_R_-values under long-term exposure to moist, below-ground conditions in freezing climates. The following_R_-values
    shall be used to determine insulation thicknesses required for this application: Type II expanded polystyrene (EPS)-3.2 R per inch for vertical insulation and 2.6 R per inch for
    horizontal insulation; Type IX expanded polystyrene (EPS)-3.4 R per inch for vertical insulation and 2.8 R per inch for horizontal insulation; Types IV, V, VI, VII, and X extruded
    polystyrene (XPS)-4.5 R per inch for vertical insulation and 4.0 R per inch for horizontal insulation.
    d. Vertical insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.
    e. Horizontal insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.|For SI: 1 inch = 25.4 mm, °C = [(°F) – 32]/1.8.
    a. Insulation requirements are for protection against frost damage in heated buildings. Greater values could be required to meet energy conservation standards.
    b. See Figure R403.3(2) or Table R403.3(2) for Air-Freezing Index values.
    c. Insulation materials shall provide the stated minimum_R_-values under long-term exposure to moist, below-ground conditions in freezing climates. The following_R_-values
    shall be used to determine insulation thicknesses required for this application: Type II expanded polystyrene (EPS)-3.2 R per inch for vertical insulation and 2.6 R per inch for
    horizontal insulation; Type IX expanded polystyrene (EPS)-3.4 R per inch for vertical insulation and 2.8 R per inch for horizontal insulation; Types IV, V, VI, VII, and X extruded
    polystyrene (XPS)-4.5 R per inch for vertical insulation and 4.0 R per inch for horizontal insulation.
    d. Vertical insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.
    e. Horizontal insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.|For SI: 1 inch = 25.4 mm, °C = [(°F) – 32]/1.8.
    a. Insulation requirements are for protection against frost damage in heated buildings. Greater values could be required to meet energy conservation standards.
    b. See Figure R403.3(2) or Table R403.3(2) for Air-Freezing Index values.
    c. Insulation materials shall provide the stated minimum_R_-values under long-term exposure to moist, below-ground conditions in freezing climates. The following_R_-values
    shall be used to determine insulation thicknesses required for this application: Type II expanded polystyrene (EPS)-3.2 R per inch for vertical insulation and 2.6 R per inch for
    horizontal insulation; Type IX expanded polystyrene (EPS)-3.4 R per inch for vertical insulation and 2.8 R per inch for horizontal insulation; Types IV, V, VI, VII, and X extruded
    polystyrene (XPS)-4.5 R per inch for vertical insulation and 4.0 R per inch for horizontal insulation.
    d.

  • § 1.8. High relevance — show source text

    4 mm, °C = [(°F) – 32]/1.8.
    a. Insulation requirements are for protection against frost damage in heated buildings. Greater values could be required to meet energy conservation standards.
    b. See Figure R403.3(2) or Table R403.3(2) for Air-Freezing Index values.
    c. Insulation materials shall provide the stated minimum_R_-values under long-term exposure to moist, below-ground conditions in freezing climates. The following_R_-values
    shall be used to determine insulation thicknesses required for this application: Type II expanded polystyrene (EPS)-3.2 R per inch for vertical insulation and 2.6 R per inch for
    horizontal insulation; Type IX expanded polystyrene (EPS)-3.4 R per inch for vertical insulation and 2.8 R per inch for horizontal insulation; Types IV, V, VI, VII, and X extruded
    polystyrene (XPS)-4.5 R per inch for vertical insulation and 4.0 R per inch for horizontal insulation.
    d. Vertical insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.
    e. Horizontal insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.|For SI: 1 inch = 25.4 mm, °C = [(°F) – 32]/1.8.
    a. Insulation requirements are for protection against frost damage in heated buildings. Greater values could be required to meet energy conservation standards.
    b. See Figure R403.3(2) or Table R403.3(2) for Air-Freezing Index values.
    c. Insulation materials shall provide the stated minimum_R_-values under long-term exposure to moist, below-ground conditions in freezing climates. The following_R_-values
    shall be used to determine insulation thicknesses required for this application: Type II expanded polystyrene (EPS)-3.2 R per inch for vertical insulation and 2.6 R per inch for
    horizontal insulation; Type IX expanded polystyrene (EPS)-3.4 R per inch for vertical insulation and 2.8 R per inch for horizontal insulation; Types IV, V, VI, VII, and X extruded
    polystyrene (XPS)-4.5 R per inch for vertical insulation and 4.0 R per inch for horizontal insulation.
    d. Vertical insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.
    e. Horizontal insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.|For SI: 1 inch = 25.4 mm, °C = [(°F) – 32]/1.8.
    a. Insulation requirements are for protection against frost damage in heated buildings. Greater values could be required to meet energy conservation standards.
    b. See Figure R403.3(2) or Table R403.3(2) for Air-Freezing Index values.
    c. Insulation materials shall provide the stated minimum_R_-values under long-term exposure to moist, below-ground conditions in freezing climates.

  • § 25.4 High relevance — show source text

    Vertical insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.
    e. Horizontal insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.|For SI: 1 inch = 25.4 mm, °C = [(°F) – 32]/1.8.
    a. Insulation requirements are for protection against frost damage in heated buildings. Greater values could be required to meet energy conservation standards.
    b. See Figure R403.3(2) or Table R403.3(2) for Air-Freezing Index values.
    c. Insulation materials shall provide the stated minimum_R_-values under long-term exposure to moist, below-ground conditions in freezing climates. The following_R_-values
    shall be used to determine insulation thicknesses required for this application: Type II expanded polystyrene (EPS)-3.2 R per inch for vertical insulation and 2.6 R per inch for
    horizontal insulation; Type IX expanded polystyrene (EPS)-3.4 R per inch for vertical insulation and 2.8 R per inch for horizontal insulation; Types IV, V, VI, VII, and X extruded
    polystyrene (XPS)-4.5 R per inch for vertical insulation and 4.0 R per inch for horizontal insulation.
    d. Vertical insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.
    e. Horizontal insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.|For SI: 1 inch = 25.4 mm, °C = [(°F) – 32]/1.8.
    a. Insulation requirements are for protection against frost damage in heated buildings. Greater values could be required to meet energy conservation standards.
    b. See Figure R403.3(2) or Table R403.3(2) for Air-Freezing Index values.
    c. Insulation materials shall provide the stated minimum_R_-values under long-term exposure to moist, below-ground conditions in freezing climates. The following_R_-values
    shall be used to determine insulation thicknesses required for this application: Type II expanded polystyrene (EPS)-3.2 R per inch for vertical insulation and 2.6 R per inch for
    horizontal insulation; Type IX expanded polystyrene (EPS)-3.4 R per inch for vertical insulation and 2.8 R per inch for horizontal insulation; Types IV, V, VI, VII, and X extruded
    polystyrene (XPS)-4.5 R per inch for vertical insulation and 4.0 R per inch for horizontal insulation.
    d. Vertical insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.
    e. Horizontal insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.|

  • § 0.280. Medium relevance — show source text

    Spandrel panels and glass curtain walls. A minimum of R-4, or the area-weighted average U -factor of the wall assembly shall not exceed U-0.280. Exception to Section 141.0(b)1B: Light and heavy mass walls. C. Floor insulation. For the altered portion of raised floors that separate conditioned spaces from unconditioned spaces or ambient air shall meet the applicable requirements of Items 1 through 3 below:

    1. Raised framed floors. A minimum of R-11 insulation between framing members, or the area-weighted average U -factor of the floor assembly shall not exceed the U -factor of U-0.071.
    2. Raised mass floors in hotel/motel guest rooms. A minimum of R-6 insulation, or the area-weighted average U -factor of the floor assembly shall not exceed the U -factor of U-0.111.
    3. Raised mass floors in other occupancies. No minimum U -factor requirement. D . Fan energy index: New fan systems serving an existing building shall meet the requirements of Section 120.10. E. Exterior windows. Fenestration alterations other than repairs shall meet the following requirements:
    4. Vertical fenestration alterations. Where over 150 square feet of the entire building’s vertical fenestration is replaced, the maximum U -factor of the replaced units shall not exceed U-0.58.
    5. Added vertical fenestration. Where over 50 square feet of vertical fenestration is added, it shall meet the requirements of Section 120.7(d). Where 50 square feet or less of vertical fenestration is added, this requirement shall not apply.
    6. Prescriptive approach. The altered components of the envelope, or space conditioning, lighting, electrical power distribution and water heating systems, and any newly installed equipment serving the alteration, shall meet the applicable requirements of Sections 110.0 through 110.9, Sections 120.0 through 120.6, and Sections 120.9 through 130.5.

    Exception to Section 141.0(b)2: The requirements of Section 120.2(i) shall not apply to alterations of spaceconditioning systems or components. A. Fenestration alterations other than repair and those subject to Section 141.0(b)2 shall meet the requirements below: i. Vertical fenestration alterations shall meet the requirements in Table 141.0-A. ii. Added vertical fenestration shall meet the requirements of Table 140.3-B, C or D. iii. All altered or newly installed skylights shall meet the requirements of Table 140.3-B, C or D. Exception 1 to Section 141.0(b)2Ai: In an alteration, where 150 square feet or less of the entire building's vertical fenestration is replaced, RSHGC and VT requirements of Table 141.0-A shall not apply. Exception 2 to Section 141.0(b)2Aii: In an alteration, where 50 square feet or less of vertical fenestration is added, RSHGC and VT requirements of Table 140.3-B, C or D shall not apply. Exception 3 to Section 141.0(b)2Aiii: In an alteration, where 50 square feet or less of skylight is added, SHGC and VT requirements of Table 140.3-B, C or D shall not apply. NOTE: Glass replaced in an existing sash and frame or sashes replaced in an existing frame are considered repairs.

  • § 7.5 Medium relevance — show source text

    3/4″ thick 2:1:8; 2:1:10
    lime Portland cement plaster over metal
    lath on both sides of wall.|See
    Note 23|30 min||1||17, 21,
    23|1/2| |W-5-W-59|5″|2″ × 4″ stud wall;3/4″ thick 1:5; 1:7.5 lime
    plaster on metal lath on both sides of
    wall.|See
    Note 23|30 min||1||17, 21,
    23|1/2| |W-5-W-60|5″|2″ × 4″ stud wall;3/4″ thick 1:1/30:2; 1:1/30:3
    Portland cement, asbestos fiber plaster
    on metal lath on both sides of wall.|See
    Note 23|45 min||1||17, 21,
    23|3/4| |W-5-W-61|5″|2″ × 4″ stud wall;3/4″ thick 1:2; 1:3
    Portland cement plaster on metal lath on
    both sides of wall.|See
    Note 23|30 min||1||17, 21,
    23|1/2| |W-5-W-62|5″|2″ × 4″ stud wall;3/4″ thick neat gypsum
    plaster on metal lath on both sides of
    wall.|N/A|1 hr
    30 min||1||17, 22,
    24|11/2| |W-5-W-63|5″|2″ × 4″ stud wall;3/4″ thick neat gypsum
    plaster on metal lath on both sides of
    wall.|See
    Note 23|1 hr
    30 min||1||17, 21,
    23|11/2| |W-5-W-64|5″|2″ × 4″ stud wall;3/4″ thick 1:2; 1:2 gypsum
    plaster on metal lath on both sides of
    wall; insulated cavities.|See
    Note 23|1 hr
    30 min||1||17, 18,
    21, 23|11/2| |W-5-W-65|5″|2″ × 4″ stud wall; same as W-5-W-64 but
    cavities not insulated.|See
    Note 23|1 hr||1||17, 21,
    23|1| |W-5-W-66|5″|2″ × 4″ stud wall;3/4″ thick 1:2; 1:3 gypsum
    plaster on metal lath on both sides of
    wall; insulated cavities.|See
    Note 23|1 hr
    15 min||1||17, 18,
    21, 23|11/4| |W-5-W-67|51/16″|Same as W-5-W-49 except cavity insula-
    tion of 1.75 lbs/ft2 mineral wool bats;
    rating applies when either wall side
    exposed to fire.|See
    Note 23|1 hr
    15 min||1||23, 25,
    26|11/4| |W-5-W-68|51/4″|2″ × 4″ stud wall,7/8″ thick 1:2;

  • § 7-8 Medium relevance — show source text

    The insulation materials used to satisfy
    this option also contribute to but do not supersede the thermal envelope requirements of Chapter 11.|

    7-8 2025 CALIFORNIA RESIDENTIAL CODE

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    WALL COVERING

    TABLE R702.7(4)—CONTINUOUS INSULATION WITH CLASS I OR II RESPONSIVE VAPOR RETARDER Col2
    CLIMATE ZONE PERMITTED CONDITIONSa
    3 Continuous insulation with_R_-value ≥ 2.
    4, 5 and 6 Continuous insulation with_R_-value ≥ 3 over 2 × 4 wall.
    Continuous insulation with_R_-value ≥ 5 over 2 × 6 wall.
    7 Continuous insulation with_R_-value ≥ 5 over 2 × 4 wall.
    Continuous insulation with_R_-value ≥ 7.5 over 2 × 6 wall.
    8 Continuous insulation with_R_-value ≥ 7.5 over 2 × 4 wall.
    Continuous insulation with_R_-value ≥ 10 over 2 × 6 wall.
    a. The requirements in this table apply only to insulation used to control moisture in order to permit the use of Class II vapor retarders. The insulation materials used to satisfy
    this option also contribute to but do not supersede the thermal envelope requirements of Chapter 11.    		 a. The requirements in this table apply only to insulation used to control moisture in order to permit the use of Class II vapor retarders. The insulation materials used to satisfy
    this option also contribute to but do not supersede the thermal envelope requirements of Chapter 11.
    TABLE R702.7(5)—CONTINUOUS INSULATION ON WALLS WITHOUT A CLASS I, II OR III INTERIOR VAPOR RETARDERa Col2
    CLIMATE ZONE PERMITTED CONDITIONSb, c
    4 Continuous insulation with_R_-value ≥ 4.5
    5 Continuous insulation with_R_-value ≥ 6.5
    6 Continuous insulation with_R_-value ≥ 8.5
    7 Continuous insulation with_R_-value ≥ 11.5
    8 Continuous insulation with_R_-value ≥ 14
    a. The total insulating value of materials to the interior side of the exterior continuous insulation, including any cavity insulation, shall not exceed R-5. Where the R-value of
    materials to the interior side of the exterior continuous insulation exceeds R-5, an approved design shall be required.
    b. A water vapor control material layer having a permeance not greater than 1 perm in accordance with ASTM E96 Procedure A (dry cup) shall be placed on the exterior side of
    the wall and to the interior side of the exterior continuous insulation. The exterior continuous insulation shall be permitted to serve as the vapor control layer where, at its
    installed thickness or with a facer on its interior face, the exterior continuous insulation is a Class I or II vapor retarder.
    c. The requirements in this table apply only to insulation used to control moisture in order to allow walls without a Class I, II or III interior vapor retarder. The insulation materi-
    als used to satisfy this option also contribute to but do not supersede the thermal envelope requirements of the_California Energy Code_.    		 a. The total insulating value of materials to the interior side of the exterior continuous insulation, including any cavity insulation, shall not exceed R-5.
  • § 0.20 Medium relevance — show source text

    b. Steep-sloped roofs in Climate Zones 2 through 15 shall have a minimum aged solar reflectance of 0.20 and a minimum thermal emittance of 0.75, or a minimum SRI of 16. Exception to Section 140.3(a)1A: Roof area covered by building integrated photovoltaic panels and building integrated solar thermal panels are not required to meet the minimum requirements for solar reflectance, thermal emittance, or SRI.

    B. Roof insulation. Roofs shall have an overall assembly U -factor no greater than the applicable value in Table 140.3B, C or D, and where required by Section 110.8 and 120.7(a)3, insulation shall be placed in direct contact with a roof or drywall ceiling.

    TABLE 140.3—ROOF/CEILING INSULATION TRADEOFF FOR AGED SOLAR REFLECTANCE—NONRESIDENTIAL BUILDINGS Col2 Col3 Col4
    Aged Solar
    Reflectance    		 Metal Building Climate Zone
    1-16U-factor    		 Wood Framed and Other
    Climate Zones
    6-8U-factor    		 Wood Framed and Other
    All Other Climate Zones
    U-factor
    0.62-0.56 0.038 0.045 0.032
    0.55-0.46 0.035 0.042 0.030
    0.45-0.36 0.033 0.039 0.029
    0.35-0.25 0.031 0.037 0.028

    1. Exterior walls. Exterior walls shall have an overall assembly U -factor no greater than the applicable value in Table 140.3-B, C or D.

    2. Demising walls. Demising walls shall meet the requirements of Section 120.7(b)7. Vertical windows in demising walls between conditioned and unconditioned spaces shall have an area-weighted average U-factor no greater than the applicable value in Table 140.3-B, C or D.

    3. Exterior floors and soffits. Exterior floors and soffits shall have an overall assembly U -factor no greater than the applicable value in Table 140.3-B, C or D.

    4. Exterior Windows. Vertical windows in exterior walls shall:

    A. Percent window area shall be limited in accordance with the applicable requirements of i and ii below: i. a west-facing area no greater than 40 percent of the gross west-facing exterior wall area, or 6 feet times the west-facing display perimeter, whichever is greater; ii. a total area no greater than 40 percent of the gross exterior wall area, or 6 feet times the display perimeter, whichever is greater; and

    Note: Demising walls are not exterior walls, and therefore demising wall area is not part of the gross exterior wall area or display perimeter and windows in demising walls are not part of the window area.

    Exception to Section 140.3(a)5A : Conditioned greenhouses. The requirements of Section 120.6(h)3 apply. B. Have an area-weighted average U -factor no greater than the applicable value in Table 140.3-B, C or D.

  • § 2.5 Medium relevance — show source text

    Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder_.|a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls, use of a Class I vapor retarder that is not a responsive vapor retarder on the interior side with a Class I vapor retarder on the exterior side shall require an
    approved design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder    .|a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls, use of a Class I vapor retarder that is not a responsive vapor retarder on the interior side with a Class I vapor retarder on the exterior side shall require an
    approved design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder    ._|

    TABLE R702.7(3)—CLASS III VAPOR RETARDERS Col2
    ** CLIMATE ZONE** ** CLASS III VAPOR RETARDERS PERMITTED FOR:a, b**
    Marine 4 Vented cladding over wood structural panels.
    Marine 4 Vented cladding over fiberboard.
    Marine 4 Vented cladding over gypsum.
    Marine 4 Continuous insulation with_R_-value ≥ 2.5 over 2 × 4 wall.
    Marine 4 Continuous insulation with_R_-value ≥ 3.75 over 2 × 6 wall.
    5 Vented cladding over wood structural panels.
    5 Vented cladding over fiberboard.
    5 Vented cladding over gypsum.
    5 Continuous insulation with_R_-value ≥ 5 over 2 × 4 wall.
    5 Continuous insulation with_R_-value ≥ 7.5 over 2 × 6 wall.
    6 Vented cladding over fiberboard.
    6 Vented cladding over gypsum.
    6 Continuous insulation with_R_-value ≥ 7.5 over 2 × 4 wall.
    6 Continuous insulation with_R_-value ≥ 11.25 over 2 × 6 wall.
    7 Continuous insulation with_R_-value ≥ 10 over 2 × 4 wall.
    7 Continuous insulation with_R_-value ≥ 15 over 2 × 6 wall.
    8 Continuous insulation with_R_-value ≥ 12.5 over 2 × 4 wall.
    Continuous insulation with_R_-value ≥ 20 over 2 × 6 wall.
    a.
  • § 150.2 Medium relevance — show source text

    Exception 3 to Section 150.2(b)1Ii: Roof constructions with a weight of at least 25 lb/ft [2] are not required to comply with the minimum requirements for aged solar reflectance and thermal emittance, or SRI. ii. Low-sloped roofs. Low-sloped roofs shall meet the following: a. New roofing products in Climate Zones 4 and 6 through 15 shall have an aged solar reflectance equal to or greater than 0.63 and a thermal emittance equal or greater than 0.75, or a minimum SRI of 75. Exception 1 to Section 150.2(b)1Iiia: The aged solar reflectance can be met by using insulation at the roof deck specified in Table 150.2-E.

    TABLE 150.2-E—AGED SOLAR REFLECTANCE INSULATION TRADE-OFF TABLE Col2 Col3
    MINIMUM AGED
    SOLAR REFLECTANCE    		 ROOF DECK CONTINUOUS INSULATION
    R-VALUE (Climate Zones 6–7)    		 ROOF DECK CONTINUOUS INSULATION
    R-VALUE (Climate Zones 2, 4 and 8–15)
    0.60 2 16
    0.55 4 18
    0.50 6 20
    0.45 8 22
    No requirement 10 24

    Exception 2 to Section 150.2(b)1Iiia: Roof area covered by building integrated photovoltaic panels or building integrated solar thermal panels is not required to meet the minimum requirements for aged solar reflectance, thermal emittance or SRI.

    Exception 3 to Section 150.2(b)1Iiia: Roof constructions with a weight of at least 25 lb/ft [2] are not required to comply with the minimum requirements for aged solar reflectance and thermal emittance, or SRI.

    2025 CALIFORNIA ENERGY CODE 193

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    SINGLE-FAMILY RESIDENTIAL BUILDINGS—ADDITIONS AND ALTERATIONS TO EXISTING RESIDENTIAL BUILDINGS

    b. Roofs shall be insulated to the levels specified in Table 150.2-F.

    TABLE 150.2-F—INSULATION REQUIREMENTS FOR ROOF ALTERATIONS Col2 Col3
    CLIMATE ZONE CONTINUOUS INSULATIONR-VALUE ROOF ASSEMBLY
    U-FACTOR
    3, 5–7 N.A. N.A.
    1, 2, 4, 8–16 R-14 0.039

    Exception 1 to Section 150.2(b)1Iiib: Existing roofs with R-10 or greater continuous insulation above or below the roof deck; or Exception 2 to Section 150.2(b)1Iiib: Existing roofs with an assembly U -factor of 0.056 or less or that are insulated with at least R-19 insulation between the roof rafters and in contact with the roof deck in Climate Zones 1, 2, 4, and 8 through 10; or Exception 3 to Section 150.2(b)1Iiib: The continuous insulation requirements of Table 150.

  • California Energy Code Medium relevance — show source text
    TABLE R702.7(2)—VAPOR RETARDER OPTIONS Col2 Col3 Col4
    CLIMATE ZONE VAPOR RETARDER CLASS VAPOR RETARDER CLASS VAPOR RETARDER CLASS
    CLIMATE ZONE CLASS Ia CLASS IIa CLASS III
    1, 2 Not Permitted Not Permitted Permitted
    3, 4 (except Marine 4) Not Permitted Permittedc Permitted
    Marine 4, 5, 6, 7, 8 Permittedb, c Permittedc See Table R702.7(3)
    a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls, use of a Class I vapor retarder that is not a responsive vapor retarder on the interior side with a Class I vapor retarder on the exterior side shall require an
    approved design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder_._    		 a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls, use of a Class I vapor retarder that is not a responsive vapor retarder on the interior side with a Class I vapor retarder on the exterior side shall require an
    approved design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder_._    		 a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls, use of a Class I vapor retarder that is not a responsive vapor retarder on the interior side with a Class I vapor retarder on the exterior side shall require an
    approved design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder_._    		 a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls, use of a Class I vapor retarder that is not a responsive vapor retarder on the interior side with a Class I vapor retarder on the exterior side shall require an
    approved design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing or insulated siding installed as continuous insulation on the exterior side of
    frame walls, the continuous insulation shall comply with Table R702.7(4) and the Class I or II vapor retarder shall be a responsive vapor retarder_._

    |TABLE R702.

  • § 4.420 Medium relevance — show source text

    410|≥4.420|NA|AHRI
    550/590| |Water
    source
    electri-
    cally
    operated
    positive
    displace-
    ment|<75|≤0.7885
    FL
    ≤0.6316
    IPLV.IP|≤0.7875
    FL
    ≤0.5145
    IPLV.IP|75/655|NA|NA|NA|≥3.550|NA|NA|NA|6.150|6.150| |Water
    source
    electri-
    cally
    operated
    positive
    displace-
    ment|≥75
    and
    <150|≤0.7579
    FL
    ≤0.5895
    IPLV.IP|≤0.7140
    FL
    ≤0.4620
    IPLV.IP|54/445|≥4.640|≥3.680|≥2.680|NA|≥8.330|≥6.410|≥4.420|NA|NA| |Water
    source
    electri-
    cally
    operated
    positive
    displace-
    ment|≥75
    and
    <150|≤0.7579
    FL
    ≤0.5895
    IPLV.IP|≤0.7140
    FL
    ≤0.4620
    IPLV.IP|75/655|NA|NA|NA|≥3.550|NA|NA|NA|6.150|6.150| |Water
    source
    electri-
    cally
    operated
    positive
    displace-
    ment|≥150
    and
    <300|≤0.6947
    FL
    ≤0.5684
    IPLV.IP|≤0.7140
    FL
    ≤0.4620
    IPLV.IP|54/445|≥4.640|≥3.680|≥2.680|NA|≥8.330|≥6.410|≥4.420|NA|NA| |Water
    source
    electri-
    cally
    operated
    positive
    displace-
    ment|≥150
    and
    <300|≤0.6947
    FL
    ≤0.5684
    IPLV.IP|≤0.7140
    FL
    ≤0.4620
    IPLV.IP|75/655|NA|NA|NA|≥3.550|NA|NA|NA|6.150|6.150| |Water
    source
    electri-
    cally
    operated
    positive
    displace-
    ment|≥300
    and
    <600|≤0.6421
    FL
    ≤0.5474
    IPLV.IP|≤0.6563
    FL
    ≤0.4305
    IPLV.IP|54/445|≥4.930|≥3.960|≥2.970|NA|≥8.900|≥6.

  • California Energy Code Medium relevance — show source text

    |100 psf|1 hr
    23 min|||7|1, 2|11/3| |F/C-4-RC-9|4″|4″ deep (4370 psi);1/4″ reinforcement bars
    at 6″ pitch with3/4″ cover;1/4″ main rein-
    forcement bars at 4″ pitch perpendicular
    with1/2″ cover; 13′1″ span restrained.|150 psf|2 hrs|||7|1, 3|2| |F/C-4-RC-10|4″|4″ thick (5140 psi) deck;1/4″ reinforce-
    ment bars at 71/2″ pitch with7/8″ cover;3/8″
    main reinforcement bars at 33/4″ pitch
    perpendicular with1/2″ cover; 13′1″ span
    restrained.|140 psf|1 hr
    16 min|||7|1, 5|11/4| |F/C-4-RC-11|4″|4″ thick (4000 psi) concrete deck;
    3″ × 11/2″ × 4 lbs R.S.J.; 2′6″ C.R.S.; flush
    with top surface; 4″ × 6″ x 13 SWG mesh
    reinforcement 1″ from bottom of slab; 6′6″
    span restrained.|150 psf|2 hrs|||7|1, 3|2| |F/C-4-RC-12|4″|4″ deep (2380 psi) concrete deck;
    3″ × 11/2″ × 4 lbs R.S.J.; 2′6″ C.R.S.; flush
    with top surface; 4″ × 6″ x 13 SWG mesh
    reinforcement 1″ from bottom surface;
    6′6″ span restrained.|150 psf|1 hr
    3 min|||7|1, 2|1| |F/C-4-RC-13|41/2″|41/2″ thick (5200 psi) deck;1/4″ reinforce-
    ment bars at 71/4″ pitch with7/8″ cover;3/8″
    main reinforcement bars at 33/4″ pitch
    perpendicular with1/2″ cover; 13′1″ span
    restrained.|140 psf|2 hrs|||7|1, 3|2| |F/C-4-RC-14|41/2″|41/2″ deep (2525 psi) concrete deck;1/4″
    reinforcement bars at 71/2″ pitch with7/8″
    cover;3/8″ main reinforcement bars at
    33/8″ pitch perpendicular with1/2″ cover;
    13′1″ span restrained.|150 psf|42 min|||7|1, 5|2/3| |F/C-4-RC-15|41/2″|41/2″ deep (4830 psi) concrete deck;
    11/2″ × No.

  • § 110.0 Medium relevance — show source text

    ** The altered components of the envelope, or space conditioning, lighting, electrical power distribution and water heating systems, and any newly installed equipment serving the alteration, shall meet the applicable requirements of Sections 110.0 through 110.9, Sections 120.0 through 120.6, and Sections 120.9 through 130.5.

    Exception to Section 141.0(b)2: The requirements of Section 120.2(i) shall not apply to alterations of spaceconditioning systems or components. A. Fenestration alterations other than repair and those subject to Section 141.0(b)2 shall meet the requirements below: i. Vertical fenestration alterations shall meet the requirements in Table 141.0-A. ii. Added vertical fenestration shall meet the requirements of Table 140.3-B, C or D. iii. All altered or newly installed skylights shall meet the requirements of Table 140.3-B, C or D. Exception 1 to Section 141.0(b)2Ai: In an alteration, where 150 square feet or less of the entire building's vertical fenestration is replaced, RSHGC and VT requirements of Table 141.0-A shall not apply. Exception 2 to Section 141.0(b)2Aii: In an alteration, where 50 square feet or less of vertical fenestration is added, RSHGC and VT requirements of Table 140.3-B, C or D shall not apply. Exception 3 to Section 141.0(b)2Aiii: In an alteration, where 50 square feet or less of skylight is added, SHGC and VT requirements of Table 140.3-B, C or D shall not apply. NOTE: Glass replaced in an existing sash and frame or sashes replaced in an existing frame are considered repairs. In these cases, Section 141.0(c) requires that the replacement be at least equivalent to the original in performance.

    TABLE 141.0-A—ALTERED VERTICAL FENESTRATION MAXIMUM U-FACTOR AND MAXIMUM RSHGC Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14 Col15 Col16 Col17
    CLIMATE
    ZONE    		 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
    U-factor 0.47 0.47 0.58 0.47 0.58 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47
    RSHGC 0.41 0.31 0.41 0.31 0.41 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.41
    VT See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.
  • § 141.0 Medium relevance — show source text
    TABLE 141.0-A—ALTERED VERTICAL FENESTRATION MAXIMUM U-FACTOR AND MAXIMUM RSHGC Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14 Col15 Col16 Col17
    CLIMATE
    ZONE    		 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
    U-factor 0.47 0.47 0.58 0.47 0.58 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47
    RSHGC 0.41 0.31 0.41 0.31 0.41 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.41
    VT See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones. See Table 140.3-B, C and D for all climate zones.

    150 2025 CALIFORNIA ENERGY CODE

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    NONRESIDENTIAL AND HOTEL/MOTEL OCCUPANCIES— ADDITIONS, ALTERATIONS AND REPAIRS

    B. Existing roofs of a nonresidential or hotel/motel building being replaced, recovered or recoated, as defined in Section 100.1(b) and Title 24, Part 2, Chapter 2, shall meet the requirements of Section 110.8(i). When roofs with more than 50 percent of the roof area or more than 2,000 square feet of roof, whichever is less, are being altered the requirements of i and ii apply: i. Roofing products shall comply with requirements in Section 140.3(a)1A.

  • § 1404.3 Medium relevance — show source text
    TABLE 1404.3(2)—VAPOR RETARDER OPTIONS Col2 Col3 Col4
    CLIMATE ZONE VAPOR RETARDER CLASS VAPOR RETARDER CLASS VAPOR RETARDER CLASS
    CLIMATE ZONE Ia IIa III
    1, 2 Not permitted Not Permitted Permitted
    3 Not permitted Permittedc Permitted
    4 (except Marine) Not permitted Permittedc See Table 1404.3(3)
    Marine 4, 5, 6, 7, 8 Permittedb, c Permittedc See Table 1404.3(3)
    a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls with a Class I vapor retarder on the exterior side, use of a Class I interior vapor retarder that is not a responsive vapor retarder shall require an_approved_ design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing installed as continuous insulation on the exterior side of frame walls, the
    continuous insulation shall comply with Table 1404.3(4) and the Class I or II vapor retarder shall be a responsive vapor retarder.    		 a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls with a Class I vapor retarder on the exterior side, use of a Class I interior vapor retarder that is not a responsive vapor retarder shall require an_approved_ design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing installed as continuous insulation on the exterior side of frame walls, the
    continuous insulation shall comply with Table 1404.3(4) and the Class I or II vapor retarder shall be a responsive vapor retarder.    		 a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls with a Class I vapor retarder on the exterior side, use of a Class I interior vapor retarder that is not a responsive vapor retarder shall require an_approved_ design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing installed as continuous insulation on the exterior side of frame walls, the
    continuous insulation shall comply with Table 1404.3(4) and the Class I or II vapor retarder shall be a responsive vapor retarder.    		 a. A responsive vapor retarder shall be allowed on the interior side of any frame wall in all climate zones.
    b. In frame walls with a Class I vapor retarder on the exterior side, use of a Class I interior vapor retarder that is not a responsive vapor retarder shall require an_approved_ design.
    c. Where a Class I or II vapor retarder is used in combination with foam plastic insulating sheathing installed as continuous insulation on the exterior side of frame walls, the
    continuous insulation shall comply with Table 1404.3(4) and the Class I or II vapor retarder shall be a responsive vapor retarder.
    TABLE 1404.3(3)—CLASS III VAPOR RETARDERS Col2
    ZONE **CLASS III VAPOR RETARDERS PERMITTED FOR:a,
  • California Energy Code Medium relevance — show source text


    2
    5
    10
    15|36
    38
    51
    NA
    NA|93
    69
    63
    NA
    NA|57
    47
    44
    39
    NA|56
    57
    75
    95
    NA|190
    136
    128
    116
    NA|111
    93
    86
    79
    72|80
    80
    102
    128
    158|325
    225
    216
    201
    186|186
    149
    140
    131
    124|116
    115
    144
    182
    220|499
    337
    326
    308
    290|283
    224
    217
    203
    192|153
    148
    182
    228
    272|713
    473
    459
    438
    418|388
    314
    298
    284
    269| |20|0
    2
    5
    10
    15
    20|35
    37
    50
    NA
    NA
    NA|96
    74
    68
    NA
    NA
    NA|60
    50
    47
    41
    NA
    NA|54
    56
    73
    93
    NA
    NA|200
    148
    140
    129
    NA
    NA|118
    99
    94
    86
    80
    NA|78
    78
    100
    125
    155
    186|346
    248
    239
    223
    208
    192|201
    165
    158
    146
    136
    126|114
    113
    141
    177
    216
    254|537
    375
    363
    344
    325
    306|306
    248
    239
    224
    210
    196|149
    144
    178
    222
    264
    309|772
    528
    514
    491
    469
    448|428
    344
    334
    316
    301
    285| |30|0
    2
    5

Frequently asked questions

Where do I find the numeric U‑factor or R‑value for my climate zone?

Table 150.1‑A contains the climate‑zone specific maximum assembly U‑factors and any continuous insulation R‑values. The controlling text is §150.1(c)1 which points you to that table; consult the official Table 150.1‑A in Title 24, Part 6 to read the numeric entries.

Can I just install the R‑value listed in the Table to comply?

Only if the Table entry is presented as an R‑value option (mainly applies to mass walls or where the table explicitly lists R‑values). For framed walls the table gives an assembly U‑factor, and you must ensure the whole assembly (framing + insulation + etc.) meets that U‑factor — cavity R alone may not be sufficient.

What if my design uses both cavity and continuous insulation?

That's allowed. The code accepts cavity, continuous, or a combination provided the resulting assembly U‑factor is ≤ the Table 150.1‑A limit. Use JA4 methods to document equivalency when using non‑tabulated products.

Is field verification required?

Sometimes — Table 150.1‑A indicates where Quality Insulation Installation (QII) field verification is required; when required, follow RA3.5 verification procedures.

Can I use an alternate calculation rather than the Table?

Yes. The code allows assemblies that meet the required maximum U‑factors using an approved U‑factor calculation method that considers the thermal effects of all elements of the assembly (approval path noted in the exception to §150.1(c)1).

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California Energy Code