Title 24 · California Energy Code

What is the standard design vs proposed design in performance compliance modeling?

In plain terms: the code asks you to model your actual building (Proposed Design) and compare its yearly energy/cost metric(s) to a code‑baseline version of that same building (Standard Design). If your modeled energy (LSC and source) is equal to or lower than the standard baseline calculated by certified software, you comply.

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

A building meets the performance approach when the modeled annual energy consumption of the proposed design is no greater than the energy budget for the standard design, as calculated using Commission‑certified compliance software. The energy budget is expressed in long‑term system cost (LSC) and source energy, and is created by applying the mandatory and prescriptive requirements of the standard design to the proposed design building. See § 150.1, § 140.1, and § 170.1 for the basic rule and definitions.

The single most important rule: model the Proposed Design as‑built and compare its LSC and/or source energy against the Standard Design energy budget (standard = code-prescriptive package applied to your Proposed Design); pass if Proposed ≤ Standard.

Requirements in detail

Key defined terms (first mention bolded)

  • Standard design — the baseline building defined by applying the code’s mandatory and prescriptive requirements to the building being modeled; used to produce the energy budget. § 150.1, § 140.1, § 170.1.
  • Proposed design — the actual design you intend to build; input to the same simulation engine. The Proposed Design’s modeled energy use is compared to the Standard Design’s budget. § 150.1, § 140.1, § 170.1.
  • Long‑term system cost (LSC) — one of the energy budget metrics; the LSC budget is calculated by applying standard‑design prescriptive/mandatory requirements to the proposed building. § 150.1, § 140.1, § 170.1.
  • Source energy — the other energy budget metric; determined by applying the standard‑design prescriptive/mandatory requirements to the proposed building. § 150.1, § 140.1, § 170.1.

Decision‑relevant dimensions (table)

Dimension / question What the code requires Code Reference
Compliance test Proposed design energy consumption must be no greater than Standard design energy budget (LSC and/or Source energy). § 150.1, § 140.1, § 170.1
Energy budget metrics LSC and Source energy are the official budget outputs. § 150.1(b)1, § 140.1(a), § 170.1(a)
How Standard design is built Apply the code’s mandatory and prescriptive requirements to the Proposed Design to produce the Standard Design budget. § 150.1(b)1, § 140.1(a), § 170.1(a)
Software / method Use Commission‑certified compliance software (per Sections 10‑109(c) and 10‑116). § 150.1(b), § 140.1
Orientation / geometry The modeling baseline is created for the same geometry and orientation as the Proposed Design (notes/related sections explain this assumption). See modeling guidance; standard design assumes same geometry/orientation (see related sections).
Exceptions that can offset budget Approved community shared solar or community BESS may offset solar/BESS requirements per the Commission’s method. Exceptions in § 150.1(b)1, § 140.1(a), § 170.1(a)

Notes:

  • The rule (Proposed ≤ Standard) is stated explicitly in § 150.1, § 140.1, and § 170.1.
  • The code requires Commission‑certified software for the comparison, so manual, non‑certified spreadsheets are not acceptable for the official compliance calculation. § 150.1(b) and § 140.1 reference software certification.

Exceptions & special cases

  • Community shared solar / shared BESS: an approved community shared renewable or battery system may offset required solar/BESS credits; see the exception language in § 150.1(b)1, § 140.1(a), and § 170.1(a).
  • Multifamily / nonresidential nuance: § 170.1 and § 140.1 describe the same test but apply to different building categories (multifamily vs nonresidential). Always consult the section that applies to your occupancy. § 170.1 (multifamily) and § 140.1 (nonresidential) give the energy budget definition.
  • Source energy exceptions: § 170.1 notes a specific exception for source energy budgeting when a consumer gas/propane water heater is used — read the exception text if that applies. § 170.1(a)2.
  • Additions / alterations: the way the standard design is constructed for alterations (e.g., using existing efficiency levels vs code baseline) is covered in related sections for additions/alterations (see Sections such as 150.2, 141.0, 180.2). If your project is an addition/alteration, consult those sections directly.

If a specific modeling detail or exception you need is not present in the text above, state it and consult the applicable ACM Reference Manual or the specific Title 24 subsection (e.g., alteration rules) — the files retrieved here may not exhaust all related subsections.

Common mistakes

  • Modeling the wrong baseline: treating the Standard Design as “the same as the Proposed Design with only a few changes” rather than applying the full package of mandatory + prescriptive measures to the Proposed Design. The code defines the Standard Design as the prescriptive package applied to the proposed building—don’t confuse that with “existing conditions.” § 150.1, § 140.1, § 170.1.
  • Using non‑certified software or methods: the Standard vs Proposed comparison must be done with Commission‑certified compliance software per the referenced sections. § 150.1(b), § 140.1.
  • Forgetting both metrics: some teams check only Source Energy OR only LSC; the code expresses the budget in both metrics — confirm which metric(s) your compliance path requires to be within budget. § 150.1(b)1, § 140.1(a), § 170.1(a).
  • Geometry/orientation mismatch: the Standard Design should assume the same geometry and orientation as the Proposed Design unless a referenced exception or ACM guidance applies. Check model inputs accordingly. (See related notes / modeling rules.)

Worked example — concrete scenario

Scenario assumptions (simplified for illustration; budgets must be computed with certified software):

  • Project: small office (nonresidential) in CA climate zone X.
  • Certified compliance software is used as required (see § 140.1).

Step 1 — Standard Design budget (computed by applying mandatory + prescriptive package to the Proposed geometry):

  • Software outputs Standard Design annual LSC energy = 120 LSC‑units and Source energy = 95,000 kBtu. (These numbers are the software output — the code requires using certified software to produce them.) § 140.1(a).

Step 2 — Proposed Design modeled energy:

  • Proposed Design annual LSC energy = 110 LSC‑units and Source energy = 92,000 kBtu.

Step 3 — Compare:

  • LSC: Proposed 110 ≤ Standard 120 → pass on LSC.
  • Source energy: Proposed 92,000 ≤ Standard 95,000 → pass on Source energy.

Result: The Proposed Design meets the performance approach because modeled Proposed energy is no greater than the Standard Design budget (Per § 140.1 / performance test).

(Notes: the example uses illustrative numbers — actual LSC/source budgets and pass/fail must come from the Commission‑certified compliance software as required by § 140.1, § 150.1, or § 170.1.)

Related provisions

  • § 150.1 — Performance and prescriptive approaches for single‑family residential buildings (performance test language).
  • § 140.1 — Performance approach: energy budgets for nonresidential and hotel/motel occupancies.
  • § 170.1 — Performance approach for multifamily buildings (energy budget language and exceptions).
  • § 10‑109(c) and § 10‑116 — Commission‑certified compliance software requirements (referenced by § 150.1 and § 140.1).
  • § 150.2 / § 140.2 / § 170.2 — The prescriptive compliance approach (alternative path; see when prescriptive baseline or measures are needed).
  • Sections covering additions/alterations (e.g., § 141.0, § 150.2 notes) — these explain different rules for altered components and how the standard design is set for alterations. Consult when your project is not new construction.

Code references

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

  • § 10-109 High relevance — show source text

    (b) Performance approach. A building complies with the performance approach if the energy consumption calculated for the proposed design building is no greater than the energy budget calculated for the standard design building using Commission-certified compliance software as specified by Sections 10-109(c) and 10-116.

    1. Energy budget. The energy budget is expressed in terms of source energy and long-term system cost (LSC). A. Long-term system cost (LSC). The LSC energy budget is determined by applying the mandatory and prescriptive requirements of the standard design to the proposed design building and has two components, the Efficiency LSC and the Total LSC.

    i. The Efficiency LSC energy is the sum of the LSC energy for space-conditioning, water heating, mechanical ventilation, and the self-utilization credit.

    ii. The Total LSC energy is the sum of the Efficiency LSC energy and LSC energy from the photovoltaic system, battery energy storage systems (BESS), lighting, demand flexibility, and other plug loads. B. Source energy. The source energy budget is determined by applying the mandatory and prescriptive requirements of the standard design to the proposed design building. The source energy is the total annual source energy. Exception to Section 150.1(b)1. A community shared solar electric generation system, or other renewable electric generation system, or community shared BESS, which provides dedicated power, utility energy reduction credits, or payments for energy bill reductions to the permitted building and is approved by the Energy Commission as specified in Title 24, Part 1, Section 10-115, may offset part or all of the solar electric generation system and demand flexibility Energy Design Rating required to comply with the Standards, as calculated according to methods established by the Commission in the Residential ACM Reference Manual.

    1. Compliance demonstration requirements for performance standards. A. Certificate of compliance and application for a building permit. The application for a building permit shall include documentation pursuant to Sections 10-103(a)1 and 10-103(a)2 which demonstrates, using an approved calculation method, that the building has been designed so that its energy consumption does not exceed the standard design energy budgets for the applicable climate zone. Exception to Section 150.1(b)2A Multiple orientation: A permit applicant may demonstrate compliance with the energy budget requirements of Section 150.1(a) and (b) for any orientation of the same building model if the documentation demonstrates that the building model with its proposed designs and features would comply in each of the four cardinal orientations.

    B. Field verification. When performance of installed features, materials, components, manufactured devices or systems above the minimum specified in Section 150.1(c) is necessary for the building to comply with Section 150.1(b), or is necessary to achieve a more stringent local ordinance, field verification shall be performed in accordance with the applicable requirements in the following subsections, and the results of the verification(s) shall be documented on applicable certificates of installation pursuant to Section 10-103(a)3 and applicable certificates of verification pursuant to Section 10-103(a)5. i. EER2/SEER2/CEER/HSPF2 Rating. When performance compliance requires installation of a space-conditioning system with a rating that is greater than the minimum rating required by Table 150.1-A or specified for the standard design, the installed system shall be field verified in accordance with the procedures specified in the applicable sections of Reference Residential Appendix RA3.4. ii. **Variable capacity heat pump (VCHP) compliance option.

  • § 160.0 High relevance — show source text
    1. Dwellings that were required by a previous building permit to install a vented kitchen range hood or other kitchen exhaust fan shall install a replacement fan that meets or exceeds the airflow required by the previous building permit, or 100 cfm, whichever is greater.
    2. Dwellings that were not required to have a kitchen local ventilation exhaust system according to the conditions in either Subsection 1 or 2 above shall not be required to comply with the requirements of Section 160.0(b)2Avi.

    c. Replacement ventilation fans. New or replacement local mechanical exhaust fans shall be rated for airflow and sound in accordance with the requirements of ASHRAE 62.2 Section 7.1 and Title 24, Part 6, Section 160.0(b)2Avif. Additionally, when compliance with a specified exhaust airflow rate is required, the replacement fan shall be rated at no less than the airflow rate required for compliance.

    (c) Performance approach. The altered component(s) and any newly installed equipment serving the alteration shall meet the applicable requirements of Subsections 1, 2 and 3 below. The energy budget for alterations is expressed in terms of long-term system cost (LSC) energy.

    1. The altered components shall meet the applicable requirements of Sections 110.0 through 110.9, 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. Entirely new or complete replacement mechanical ventilation systems as these terms are used in Section 180.2(b)5A shall comply with the requirements in Section 180.2(b)5A. Altered mechanical ventilation systems shall comply with the requirements of Sections 180.2(b)5B. Entirely new or complete replacement space-conditioning systems, and entirely new or complete replacement duct systems, as these terms are used in Sections 180.2(b)2Ai and 180.2(b)2Aiia, shall comply with the requirements of Sections 160.2(a)1 and 160.3(b)5L.

    2. The standard design for an altered component shall be the higher efficiency of existing conditions or the requirements of Section 180.2(b). For components not being altered, the standard design shall be based on the unaltered existing conditions such that the standard and proposed designs for these components are identical. When the third-party verification option is specified, all components proposed for alteration for which the additional credit is taken must be verified by a certified ECC-Rater.

    3. The proposed design shall be based on the actual values of the altered components. NOTES TO SECTION 180.2(c):

    4. If an existing component must be replaced with a new component, that component is considered an altered component for the purpose of determining the standard design altered component energy budget and must meet the requirements of Section 180.2(c)2.

    5. The standard design shall assume the same geometry and orientation as the proposed design.

    6. The “existing efficiency level” modeling rules, including situations where nameplate data is not available, are described in Section 10-109(c) and Section 10-116.

    EXCEPTION 1 to Section 180.2(c): Any dual-glazed greenhouse or garden window installed as part of an alteration complies with the U- factor requirements in Section 170.2.

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  • § 10-103 High relevance — show source text
    1. Compliance demonstration requirements for performance standards. A. Certificate of compliance and application for a building permit. The application for a building permit shall include documentation pursuant to Sections 10-103(a)1 and 10-103(a)2 which demonstrates, using an approved calculation method, that the building has been designed so that its energy consumption does not exceed the standard design energy budgets for the applicable climate zone. Exception to Section 150.1(b)2A Multiple orientation: A permit applicant may demonstrate compliance with the energy budget requirements of Section 150.1(a) and (b) for any orientation of the same building model if the documentation demonstrates that the building model with its proposed designs and features would comply in each of the four cardinal orientations.

    B. Field verification. When performance of installed features, materials, components, manufactured devices or systems above the minimum specified in Section 150.1(c) is necessary for the building to comply with Section 150.1(b), or is necessary to achieve a more stringent local ordinance, field verification shall be performed in accordance with the applicable requirements in the following subsections, and the results of the verification(s) shall be documented on applicable certificates of installation pursuant to Section 10-103(a)3 and applicable certificates of verification pursuant to Section 10-103(a)5. i. EER2/SEER2/CEER/HSPF2 Rating. When performance compliance requires installation of a space-conditioning system with a rating that is greater than the minimum rating required by Table 150.1-A or specified for the standard design, the installed system shall be field verified in accordance with the procedures specified in the applicable sections of Reference Residential Appendix RA3.4. ii. Variable capacity heat pump (VCHP) compliance option. When performance compliance requires installation of a heat pump system that meets all the requirements of the VCHP compliance option specified in the ACM

    2025 CALIFORNIA ENERGY CODE 177

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    SINGLE-FAMILY RESIDENTIAL BUILDINGS—PERFORMANCE AND PRESCRIPTIVE COMPLIANCE APPROACHES

    Reference Manual, the system shall be field verified in accordance with the procedures in Reference Residential Appendix RA3.4.4.3. iii. Low leakage air handler. When performance compliance requires installation of a low leakage air-handling unit, the installed air-handling unit shall be field verified in accordance with the procedures specified in Reference Residential Appendix RA3.1.4.3.9.

    iv. Reserved.

    v. Heat pump — rated heating capacity. When performance compliance requires installation of a heat pump system, the heating capacity values at 47°F and 17°F shall be field verified in accordance with the procedures specified in Reference Residential Appendix RA3.4. vi. Whole-house fan. When performance compliance requires installation of a whole-house fan, the whole-house fan ventilation airflow rate and fan efficacy shall be field verified in accordance with the procedures in Reference Residential Appendix RA3.9. vii. Central fan ventilation cooling system. When performance compliance requires installation of a central fan ventilation cooling system, the installed system shall be field verified in accordance with the procedures in Reference Residential Appendix RA3.3.4. 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).

  • § 150.1 High relevance — show source text

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    176 2025 CALIFORNIA ENERGY CODE

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    8 SINGLE-FAMILY RESIDENTIAL BUILDINGS—PERFORMANCE

    AND PRESCRIPTIVE COMPLIANCE APPROACHES

    SECTION 150.1—PERFORMANCE AND PRESCRIPTIVE COMPLIANCE APPROACHES FOR SINGLE-FAMILY RESIDENTIAL BUILDINGS

    (a) Basic requirements. Single-family residential buildings shall meet all of the following:

    1. The applicable requirements of Sections 110.0 through 110.10.
    2. The applicable requirements of Section 150.0 (mandatory features).
    3. Either the performance standards or the prescriptive standards set forth in this section for the climate zone in which the building is located. Climate zones are shown in Reference Joint Appendix JA2–Weather/Climate Data. Exception to Section 150.1(a)3: If a single contiguous subdivision or tract falls in more than one climate zone, all buildings in the subdivision or tract may be designed to meet the performance or prescriptive standards for the climate zone that contains 50 percent or more of the dwelling units. Note: The Commission periodically updates, publishes, and makes available to interested persons and local enforcement agencies precise descriptions of the climate zones, as specified in Reference Joint Appendix JA2–Weather/Climate Data.

    Note: The requirements of Sections 150.0(a) through 150.0(r) apply to newly constructed buildings and Sections 150.2(a) and 150.2(b) specifies changes to the requirements of Sections 150.1(a) through 150.1(c) that apply to additions or alterations.

    (b) Performance approach. A building complies with the performance approach if the energy consumption calculated for the proposed design building is no greater than the energy budget calculated for the standard design building using Commission-certified compliance software as specified by Sections 10-109(c) and 10-116.

    1. Energy budget. The energy budget is expressed in terms of source energy and long-term system cost (LSC). A. Long-term system cost (LSC). The LSC energy budget is determined by applying the mandatory and prescriptive requirements of the standard design to the proposed design building and has two components, the Efficiency LSC and the Total LSC.

    i. The Efficiency LSC energy is the sum of the LSC energy for space-conditioning, water heating, mechanical ventilation, and the self-utilization credit.

    ii. The Total LSC energy is the sum of the Efficiency LSC energy and LSC energy from the photovoltaic system, battery energy storage systems (BESS), lighting, demand flexibility, and other plug loads. B. Source energy. The source energy budget is determined by applying the mandatory and prescriptive requirements of the standard design to the proposed design building. The source energy is the total annual source energy. Exception to Section 150.1(b)1. A community shared solar electric generation system, or other renewable electric generation system, or community shared BESS, which provides dedicated power, utility energy reduction credits, or payments for energy bill reductions to the permitted building and is approved by the Energy Commission as specified in Title 24, Part 1, Section 10-115, may offset part or all of the solar electric generation system and demand flexibility Energy Design Rating required to comply with the Standards, as calculated according to methods established by the Commission in the Residential ACM Reference Manual.

  • § 130.1 High relevance — show source text

    1(a)2|Required|Required| |Manual Area Controls|130.1(a)3|Only required for new or completely
    replaced circuits|Only required for new or completely
    replaced circuits| |Multi-Level Controls|130.1(b)|Required|Not Required| |Automatic Shut-off Controls|130.1(c)1|Required|Required| |Automatic Shut-off Controls|130.1(c)2|Required|Required| |Automatic Shut-off Controls|130.1(c)3|Required|Required| |Automatic Shut-off Controls|130.1(c)4|Required|Required| |Automatic Shut-off Controls|130.1(c)5|Required|Required| |Automatic Shut-off Controls|130.1(c)6|Required|Required; except for 130.1(c)6D| |Automatic Shut-off Controls|130.1(c)8|Required|Required| |Daylight Responsive
    Controls|130.1(d)|Required|Not Required| |Demand Responsive
    Controls|110.12(a) and 110.12(c)|Required|Not Required|

    B. The standard design for an altered component shall be the higher efficiency of existing conditions or the requirements of Section 141.0(b)2. For components not being altered, the standard design shall be based on the unaltered existing conditions such that the standard and proposed designs for these components are identical. C. When the third party verification option is specified, all components proposed for alteration, for which the additional credit is taken, must be verified. The Executive Director shall determine the qualifications required by the third party inspector. D. The proposed design shall be based on the actual values of the altered components.

    Notes to Section 141.0(b)3:

    1. If an existing component must be replaced with a new component, that component is considered an altered component for the purpose of determining the energy budget and must therefore meet the requirements of Section 141.0(b)3.

    2. The standard design assumes the same geometry and orientation as the proposed design.

    3. The “existing efficiency level” modeling rules, including situations where nameplate data is not available, are described in the Nonresidential ACM Reference Manual.

    Exception 1 to Section 141.0(b): When heating, cooling or service water heating for an alteration are provided by expanding existing systems, the existing systems and equipment need not comply with Sections 110.0 through 120.9 and Section 140.4 or 140.5.

    Exception 2 to Section 141.0(b): When existing heating, cooling or service water heating systems or components are moved within a building, the existing systems or components need not comply with Sections 110.0 through 120.9 and Section 140.4 or 140.5.

    Exception 3 to Section 141.0(b): Where an existing system with electric reheat is expanded when adding variable air volume (VAV) boxes to serve an alteration, total electric reheat capacity may be expanded not to exceed 20 percent of the existing installed electric capacity in any one permit and the system need not comply with Section 140.4(g). Additional electric reheat capacity in excess of 20 percent may be added subject to the requirements of Section 140.4(g).

    Exception 4 to Section 141.0(b): The requirements of Section 120.2(i) shall not apply to alterations of space-conditioning systems or components.

  • § 170.0 High relevance — show source text

    Exception to Section 170.0 (a)3: If a single development falls in more than one climate zone, all buildings in the subdivision or tract may be designed to meet the performance or prescriptive standards for the climate zone that contains 50 percent or more of the dwelling units.

    NOTE: The Commission periodically updates, publishes and makes available to interested persons and local enforcement agencies precise descriptions of the climate zones, as specified in Reference Joint Appendix JA2—Weather/Climate Data.

    NOTE: The requirements of Sections 170.1(a) through 170.2(e) apply to newly constructed buildings and Sections 180.1 and 180.2 specify changes to the requirements of Sections 170.1(a) through 170.2(e) that apply to additions or alterations.

    NOTE: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8 and 25943, Public Resources Code .

    SECTION 170.1—PERFORMANCE APPROACH

    A building complies with the performance approach if the energy consumption calculated for the proposed design building is no greater than the energy budget calculated for the standard design building using Commission-certified compliance software as specified by Sections 10-109 and 10-116 and the Alternative Calculation Method Reference Manual.

    (a) Energy budget. The energy budget is expressed in terms of long-term system cost (LSC) and source energy:

    1. Long-term system cost (LSC). The LSC energy budget is determined by applying the mandatory and prescriptive requirements of the standard design to the proposed design building and has two components, the Efficiency LSC and the Total LSC.

    A. The Efficiency LSC energy is the sum of the LSC energy for space-conditioning, water heating, mechanical ventilation, lighting and the self-utilization credit. B. The Total LSC energy is the sum of the Efficiency LSC energy and LSC energy from the photovoltaic system, battery energy storage systems (BESS), and demand flexibility. 2. Source energy. The source energy budget is determined by applying the mandatory and prescriptive requirements of the standard design, except with a consumer gas or propane water heater, to the proposed design building.

    Exception to Section 170.1(a): A community shared solar electric generation system, or other renewable electric generation system, and/or community shared BESS, that provides dedicated power, utility energy reduction credits or payments for energy bill reductions to the permitted building and is approved by the Energy Commission as specified in Title 24, Part 1, Section 10-115, may offset part or all of the solar electric generation system or BESS LSC energy required to comply with the standards, as calculated according to methods established by the Commission in the Nonresidential ACM Reference Manual.

    (b) Compliance demonstration requirements for performance standards.

    1. Certificate of Compliance and Application for a Building Permit. The application for a building permit shall include documentation pursuant to Sections 10-103(a)1 and 10-103(a)2 that demonstrates, using an approved calculation method, that the building has been designed so that its source energy and LSC energy consumption do not exceed the standard design energy budgets for the applicable climate zone.
    2. Field verification of individual dwelling unit systems.
  • § 170.1 Medium relevance — show source text

    A. The Efficiency LSC energy is the sum of the LSC energy for space-conditioning, water heating, mechanical ventilation, lighting and the self-utilization credit. B. The Total LSC energy is the sum of the Efficiency LSC energy and LSC energy from the photovoltaic system, battery energy storage systems (BESS), and demand flexibility. 2. Source energy. The source energy budget is determined by applying the mandatory and prescriptive requirements of the standard design, except with a consumer gas or propane water heater, to the proposed design building.

    Exception to Section 170.1(a): A community shared solar electric generation system, or other renewable electric generation system, and/or community shared BESS, that provides dedicated power, utility energy reduction credits or payments for energy bill reductions to the permitted building and is approved by the Energy Commission as specified in Title 24, Part 1, Section 10-115, may offset part or all of the solar electric generation system or BESS LSC energy required to comply with the standards, as calculated according to methods established by the Commission in the Nonresidential ACM Reference Manual.

    (b) Compliance demonstration requirements for performance standards.

    1. Certificate of Compliance and Application for a Building Permit. The application for a building permit shall include documentation pursuant to Sections 10-103(a)1 and 10-103(a)2 that demonstrates, using an approved calculation method, that the building has been designed so that its source energy and LSC energy consumption do not exceed the standard design energy budgets for the applicable climate zone.
    2. Field verification of individual dwelling unit systems. When performance of installed features, materials, components, manufactured devices or systems above the minimum specified in Section 170.2 is necessary for the building to comply with Section 170.1, or is necessary to achieve a more stringent local ordinance, field verification shall be performed in accordance with the applicable requirements in the following subsections, and the results of the verification(s) shall be documented on applicable Certificates of Installation pursuant to Section 10-103(a)3 and applicable Certificates of Verification pursuant to Section 10-103(a)5. A. EER2/SEER2/CEER/HSPF2 Rating. When performance compliance requires installation of a space-conditioning system with a rating that is greater than the minimum rating required by Table 170.2-K or specified for the standard

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    MULTIFAMILY BUILDINGS—PERFORMANCE AND PRESCRIPTIVE COMPLIANCE APPROACHES

    design, the installed system shall be field verified in accordance with the procedures specified in the applicable sections of Reference Residential Appendix RA3. B. Variable capacity heat pump (VCHP) compliance option. When performance compliance requires installation of a heat pump system that meets all the requirements of the VCHP compliance option specified in the ACM Reference Manual, the system shall be field verified in accordance with the procedures in Reference Residential Appendix RA3.4.4.3.

    C. Low leakage air handler. When performance compliance requires installation of a low leakage air-handling unit, the installed air handling unit shall be field verified in accordance with the procedures specified in Reference Residential Appendix RA3.1.4.3.9. D. Thermal balancing valve. When performance compliance requires installation of thermal balancing valves with variable speed circulation pump(s), the installation shall meet the procedures specified in Reference Residential Appendix RA4.4.3. E. Heat pump—rated heating capacity.

  • § 140.0 Medium relevance — show source text

    Note to Section 140.0(c): The Commission periodically updates, publishes and makes available to interested persons and local enforcement agencies precise descriptions of the climate zones, which is available by zip code boundaries depicted in the Reference Joint Appendices along with a list of the communities in each zone.

    Note to Section 140.0: The requirements of Sections 140.1 through 140.10 apply to newly constructed buildings. Section 141.0 specifies which requirements of Sections 140.1 through 140.10 also apply to additions or alterations to existing buildings.

    Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code. Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8, and 25943, Public Resources Code.

    SECTION 140.1—PERFORMANCE APPROACH: ENERGY BUDGETS

    A building complies with the performance standards if the energy consumption calculated for the proposed design building is no greater than the energy budget calculated for the standard design building using Commission-certified compliance software as specified by Sections 10-109(c) and 10-116.

    (a) Energy budget. The energy budget is expressed in terms of long-term system cost (LSC) and source energy.

    1. Long-term system cost (LSC). The LSC energy budget is determined by applying the mandatory and prescriptive requirements of the standard design to the proposed design building and has two components, the Efficiency LSC and the Total LSC.

    A. The Efficiency LSC energy is the sum of the LSC energy for space-conditioning, water heating, mechanical ventilation, and lighting. B. The Total LSC energy is the sum of the Efficiency LSC energy and LSC energy from the photovoltaic system, battery energy storage systems (BESS) and demand flexibility. 2. Source energy . The source energy budget is determined by applying the mandatory and prescriptive requirements of the standard design to the proposed design building.

    Exception to Section 140.1(a). A community shared solar electric generation system, or other renewable electric generation system, and/or community shared BESS, that provides dedicated power, utility energy reduction credits or payments for energy bill reductions to the permitted building and is approved by the Energy Commission as specified in Title 24, Part 1, Section 10-115, may offset part or all of the solar electric generation system or BESS LSC energy required to comply with the standards, as calculated according to methods established by the Commission in the Nonresidential ACM Reference Manual.

    Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code. Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8, and 25943, Public Resources Code.

    SECTION 140.2—PRESCRIPTIVE APPROACH

    To comply using the prescriptive approach a building shall be designed with and shall have constructed and installed systems and components meeting the applicable requirements of Sections 140.3 through 140.10.

  • § 110.0 Medium relevance — show source text

    (a) Additions. Additions shall meet either Item 1 or 2 below.

    1. Prescriptive approach. The envelope and lighting of the addition, any newly installed space-conditioning system, electrical power distribution system, or water-heating system; any addition to an outdoor lighting system; and any new sign installed in conjunction with an indoor or outdoor addition shall meet the applicable requirements of Sections 110.0 through 120.7, 120.9 through 130.5 and 140.2 through 140.9.
    2. Performance approach. A. The envelope and indoor lighting in the conditioned space of the addition, and any newly installed space-conditioning system, electrical power distribution system, or water-heating system, shall meet the applicable requirements of Sections 110.0 through 120.7, 120.9 through 130.5; and

    B. Either:

    i. The addition alone shall comply with Section 140.1; or ii. Existing plus addition plus alteration. The standard design for existing plus addition, plus alteration energy use is the combination of the existing building’s unaltered components to remain, existing building altered components that are the more efficient, in LSC, of either the existing conditions, or the requirements of Section 141.0(b)2, plus the proposed addition’s energy use meeting the requirements of Section 140.1. The proposed design energy use is the combination of the existing building’s unaltered components to remain and the altered component’s energy features, plus the proposed energy features of the addition.

    Exception 1 to Section 141.0(a): When heating, cooling or service water heating to an addition are provided by expanding existing systems, the existing systems and equipment need not comply with Sections 110.0 through 120.9 or Sections 140.4 through 140.5.

    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

  • § 180.2 Medium relevance — show source text

    Altered mechanical ventilation systems shall comply with the requirements of Sections 180.2(b)5B. Entirely new or complete replacement space-conditioning systems, and entirely new or complete replacement duct systems, as these terms are used in Sections 180.2(b)2Ai and 180.2(b)2Aiia, shall comply with the requirements of Sections 160.2(a)1 and 160.3(b)5L. 2. The standard design for an altered component shall be the higher efficiency of existing conditions or the requirements of Section 180.2(b). For components not being altered, the standard design shall be based on the unaltered existing conditions such that the standard and proposed designs for these components are identical. When the third-party verification option is specified, all components proposed for alteration for which the additional credit is taken must be verified by a certified ECC-Rater.

    1. The proposed design shall be based on the actual values of the altered components. NOTES TO SECTION 180.2(c):

    2. If an existing component must be replaced with a new component, that component is considered an altered component for the purpose of determining the standard design altered component energy budget and must meet the requirements of Section 180.2(c)2.

    3. The standard design shall assume the same geometry and orientation as the proposed design.

    4. The “existing efficiency level” modeling rules, including situations where nameplate data is not available, are described in Section 10-109(c) and Section 10-116.

    EXCEPTION 1 to Section 180.2(c): Any dual-glazed greenhouse or garden window installed as part of an alteration complies with the U- factor requirements in Section 170.2.

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

    EXCEPTION 2 to Section 180.2(c): Where the space in the attic or rafter area is not large enough to accommodate the required R- value, the entire space shall be filled with insulation, provided such installation does not violate Section 1203.2 of Title 24, Part 2.

    NOTE: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8 and 25943, Public Resources Code .

    SECTION 180.3—REPAIRS

    Repairs shall not increase the preexisting energy consumption of the repaired component, system or equipment.

    NOTE: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8 and 25943, Public Resources Code .

    SECTION 180.4 —WHOLE BUILDING

    Any addition or alteration may comply with the requirements of Title 24, Part 6 by meeting the requirements for the entire building.

  • § 2.5. Medium relevance — show source text

    ii. Temperature maintenance tank. Meet one of the following: A. The electrical power required to power a HPWH system temperature maintenance tank that meets the total building hot water demand as calculated and documented by the responsible person associated with the project. B. The electrical power required that meets the requirements specified for the temperature maintenance tank in Joint Appendix JA15.2.5.

    NOTE: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8 and 25943, Public Resources Code .

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    11 MULTIFAMILY BUILDINGS—PERFORMANCE

    AND PRESCRIPTIVE COMPLIANCE APPROACHES

    SECTION 170.0—GENERAL

    Multifamily buildings shall comply with the applicable requirements of Sections 170.0 through 170.2. Sections 170.0 through 170.2 apply to dwelling units and common use areas in multifamily buildings. Nonresidential occupancies in mixed occupancy buildings shall comply with nonresidential requirements in Sections 120, 130, 140 and 141.

    (a) Multifamily buildings shall meet all of the following:

    1. The applicable requirements of Sections 110.0 through 110.10.
    2. The applicable requirements of Section 160.0 (mandatory features).
    3. Either the performance standards Section 170.1 or the prescriptive standards Section 170.2 set forth in this subchapter for the climate zone in which the building is located. Climate zones are shown in Reference Joint Appendix JA2— Weather/Climate Data.

    Exception to Section 170.0 (a)3: If a single development falls in more than one climate zone, all buildings in the subdivision or tract may be designed to meet the performance or prescriptive standards for the climate zone that contains 50 percent or more of the dwelling units.

    NOTE: The Commission periodically updates, publishes and makes available to interested persons and local enforcement agencies precise descriptions of the climate zones, as specified in Reference Joint Appendix JA2—Weather/Climate Data.

    NOTE: The requirements of Sections 170.1(a) through 170.2(e) apply to newly constructed buildings and Sections 180.1 and 180.2 specify changes to the requirements of Sections 170.1(a) through 170.2(e) that apply to additions or alterations.

    NOTE: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8 and 25943, Public Resources Code .

    SECTION 170.1—PERFORMANCE APPROACH

    A building complies with the performance approach if the energy consumption calculated for the proposed design building is no greater than the energy budget calculated for the standard design building using Commission-certified compliance software as specified by Sections 10-109 and 10-116 and the Alternative Calculation Method Reference Manual.

  • § 0.20 Medium relevance — show source text

    The door area shall be the
    door area of the existing building.|If the proposed_U_-factor is < 0.20, the standard
    design shall be based on the existing_U_-factor value
    as verified. Otherwise, the standard design shall be
    based on the_U_-factor of 0.20. The door area shall
    be the door area of the existing building.| |Space-heating and space-cooling
    equipment|Table 150.1-A for equipment efficiency
    requirements; Section 150.2(b)1C for entirely new
    or complete replacement systems; Section
    150.2(b)1F for refrigerant charge verification
    requirements.|The existing efficiency levels.| |Air distribution system – duct sealing|The requirements of Sections 150.2(b)1D and 150.2(b)1E|The requirements of Sections 150.2(b)1D and 150.2(b)1E| |Air distribution system – duct insulation|The proposed efficiency levels.|The existing efficiency levels.| |Water heating systems|The requirements of Section 150.2(b)1Hii.|The existing efficiency levels.| |Roofing products|The requirements of Section 150.2(b)1I.|The requirements of Section 150.2(b)1I.| |All other measures|The proposed efficiency levels.|The existing efficiency levels.|

    C. The proposed design shall be based on the actual values of the altered components. Notes to Section 150.2(b)2:

    1. If an existing component must be replaced with a new component, that component is considered an altered component for the purpose of determining the standard design altered component energy budget and must meet the requirements of Section 150.2(b)2B.
    2. The standard design shall assume the same geometry and orientation as the proposed design.
    3. The “existing efficiency level” modeling rules, including situations where nameplate data are not available, are described in Sections 10-109(c) and 10-116. Exception 1 to Section 150.2(b): Any dual- glazed greenhouse or/garden window installed as part of an alteration complies with the U -factor requirements in Section 150.1(c)3. Exception 2 to Section 150.2(b): Where the space in the attic or rafter area is not large enough to accommodate the required R -value, the entire space shall be filled with insulation, provided such installation does not violate Section 1203.2 of Title 24, Part 2.

    (c) Whole building. Any addition or alteration may comply with the requirements of Title 24, Part 6 by meeting the requirements for the entire building.

    Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8, 25910, and 25943, Public Resources Code .

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    CALIFORNIA MECHANICAL CODE, CALIFORNIA CODE OF REGULATIONS, TITLE 24, PART 4, CHAPTER 6, DUCT SYSTEMS

Frequently asked questions

What exactly do I enter as the Proposed Design?

Enter the actual, intended building design inputs (enclosure assemblies, equipment efficiencies, PV, BESS, controls, schedules, etc.) — the Proposed Design is your as‑built intent and is the model compared against the Standard Design. See § 150.1, § 140.1, § 170.1.

How is the Standard Design generated?

The Standard Design is produced by applying the code’s mandatory and prescriptive requirements to the Proposed Design’s geometry and inputs; software creates the Standard Design energy budget in LSC and source energy. See § 150.1(b)1, § 140.1(a), § 170.1(a).

Do I need special software?

Yes — the comparison must be done using Commission‑certified compliance software (referenced by the performance sections). § 150.1(b) and § 140.1 require certified software.

Can shared community solar reduce my budget requirement?

Potentially — approved community shared solar or community BESS may offset required solar/BESS credits per the exception language in § 150.1(b)1, § 140.1(a), and § 170.1(a); these offsets must be approved and calculated per Commission methods.

If my project is an alteration, does this change the baseline?

Yes — alterations use different standard‑design rules (for example, “existing efficiency level” vs code minimum for altered components). For alterations consult the sections on additions/alterations (e.g., § 150.2, § 141.0, § 180.2) which describe how the standard design is set for altered components.

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