Title 24 · California Energy Code

How do I model existing building conditions and the 'existing efficiency level' for alterations?

When you model an alteration under California’s Energy Code, put the actual (nameplate or measured) values for the equipment you are changing into the proposed design. For the standard (baseline) design, use whichever is more efficient — the existing equipment or the prescriptive code requirement — and follow the Part‑1 modeling rules in §10‑109(c) and §10‑116 for how to enter or substitute missing existing data.

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

The performance rules for alterations require that the standard design for any altered component be the higher efficiency of the existing conditions or the prescriptive requirement for that component; the proposed design must be modeled using the actual values of the altered components. This rule is stated in § 180.2, which also directs users to the Part‑1 modeling rules for how to treat “existing efficiency level” and missing nameplate data in simulation inputs.

Plain English: When you model an alteration, use the real (measured/nameplate) values for the equipment you are changing; for the “standard” baseline, pick whichever is more efficient — the existing equipment or the prescriptive requirement — and follow the modeling rules in Part 1 for how to document or substitute missing data.

Requirements in detail

Key rules (short)

Standard design basis: use the higher efficiency between the existing conditions and the prescriptive requirement for the altered component. § 180.2.
Proposed design basis: model the actual values of the altered components (nameplate, measured, or manufacturer data). § 180.2.
Geometry/orientation: the standard design assumes the same geometry and orientation as the proposed design. § 180.2.
Existing‑efficiency modeling rules & nameplate data: detailed modeling conventions (how to treat missing nameplate data, defaults, modeling assumptions) are described in § 10‑109(c) and § 10‑116 (Part 1). § 180.2 notes this cross‑reference.

Decision table — what to model and where it comes from

Decision dimension	What to use in the Proposed Design	What to use in the Standard Design	Code Reference
Altered component efficiencies (e.g., HVAC COP/EER, water‑heater EF)	Actual values (nameplate, measured, manufacturer spec)	Higher efficiency of: existing condition OR prescriptive requirement	§ 180.2
Components not being altered	Leave as unaltered existing conditions so proposed & standard match	Standard design = unaltered existing (identical)	§ 180.2
Replacement of an existing component (component must be replaced)	Proposed design = new component actual values	That component is counted as an altered component and standard design is determined per §180.2 rules	§ 180.2 notes this.
Fenestration and door U‑factors when verifying existing	Use verified existing U/SHGC when third‑party verification is used; otherwise prescriptive defaults may apply	See fenestration tables and table exceptions (special thresholds apply)	See related tables and §180.2 notes.
Modeling assumptions (schedules, weather, thermostat setpoints)	Use Commission‑approved modeling assumptions per Part 1	Standard design uses same geometry/orientation; otherwise follows Part 1 defaults	§ 10‑109(c) and § 10‑116 (referenced by §180.2)

What “existing efficiency level” means (practical)

The code treats the existing efficiency level as the baseline efficiency you document for an existing component when running a performance calculation; the standard design compares that documented existing value to prescriptive requirements and selects the more efficient as the standard. § 180.2.
The code explicitly points modelers to Part‑1 rules that govern how to enter those existing values into Commission‑certified software and what to do if a nameplate is missing (see § 10‑109(c) and § 10‑116 as referenced).

Exceptions & special cases

If a component is moved within a building or an existing system is expanded, separate exceptions may allow older systems to remain (these exceptions are spelled out in other alteration sections such as § 141.0(b) and § 150.2(b)); check the specific occupancy/alteration section that applies to your project. file
Certain fenestration exceptions (e.g., dual‑glazed greenhouse/garden windows) are treated differently for U‑factor compliance when installed as part of an alteration — see the exception called out in the notes to § 180.2(c).
When the code specifies a third‑party verification option, existing conditions that are credited as “existing efficiency” must be verified by the required verifier (for example, an ECC‑Rater). That verification can change what you may enter for existing efficiencies. § 180.2 notes the verification requirement.

Note: The code repeatedly references the Part‑1 modeling rules for detailed procedures; the specific substitution rules for missing nameplate data live in § 10‑109(c) and § 10‑116, which are the authoritative source for how to model or default missing existing equipment data. The files I was provided reference those sections but do not include the full text of § 10‑109(c) or § 10‑116 — consult Part 1 for the exact step‑by‑step modeling rules.

Common mistakes

Treating the existing equipment as the standard design baseline instead of using the higher efficiency of existing or prescriptive requirement. Always check § 180.2.
Entering prescriptive minimums for components that are not altered (components not being altered must be modeled as existing/unaltered so proposed and standard match). § 180.2 requires the standard design for unaltered components to be based on unaltered existing conditions.
Failing to follow Part‑1 modeling rules (Section 10‑109(c) and 10‑116) when nameplate data is missing — those Part‑1 rules control allowable defaults and assumptions; they must be followed but the precise language is in Part 1.
Not using third‑party verification when the project elects that option — verified existing values can change the standard design basis and may allow existing efficiencies to be credited.

Worked example — concrete scenario

Project: Small commercial office alteration replaces one rooftop package unit (RTU) serving the altered area. Climate, building geometry unchanged.

Inputs:

Existing RTU (to be replaced): nameplate cooling capacity 6.0 tons, EER = 9.5 (measured/nameplate).
Prescriptive minimum for new RTU (per applicable table) = EER 11.0.
Proposed new RTU (actual installed): 6.0 tons, EER = 13.0.

Modeling steps and outcome (per § 180.2):

For the proposed design: model the RTU using the actual installed values — 6.0 tons, EER 13.0. § 180.2 requires proposed design based on actual values.
For the standard design altered component energy budget: determine the higher efficiency of (a) the existing condition (EER 9.5) or (b) the prescriptive requirement (EER 11.0). The higher is EER 11.0, so the standard design uses EER 11.0 for that RTU. § 180.2.
For components not being altered (e.g., envelope, lighting outside the altered scope): model them as unaltered existing so the standard and proposed match, per § 180.2.

Result: In the performance run, the RTU efficiency contributes the following:

Standard design RTU efficiency: EER 11.0 (per step 2).
Proposed design RTU efficiency: EER 13.0 (per step 1).
Because the proposed RTU is more efficient than the standard design RTU, the alteration improves the energy budget in the performance model.

Caveat: If nameplate data were missing for the existing RTU, you must follow the Part‑1 rules in § 10‑109(c) and § 10‑116 for allowable defaults or substitutions before deciding the standard design value; those Part‑1 procedures govern when you can estimate existing efficiency and what defaults are allowed. The files provided reference those sections but do not contain the full Part‑1 text.

Related provisions

§ 180.2 — Performance approach for alterations; standard/proposed design rules and notes referencing Part‑1 modeling rules.
§ 10‑109(c) — Part‑1 modeling rules and procedures; referenced by §180.2 for existing efficiency modeling (text not included in the provided files).
§ 10‑116 — Part‑1 requirements for compliance software and modeling conventions; referenced by §180.2 (text not included in the provided files).
§ 150.2(b) — Similar alteration rules for single‑family residential alterations; includes notes referencing §10‑109(c) and §10‑116 for existing efficiency modeling.
§ 141.0(b)3 — Nonresidential alteration rules that use the same standard/proposed design approach and refer to existing efficiency modeling rules.

Code references

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

§ 180.2 High 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.

§ 0.40 High relevance — show source text

| |Window film|The_U_-factor of 0.40 and
SHGC value of 0.35.|The existing fenestration in the alteration
shall be based on Tables 110.6-A and 110.6-B.| |Service water heating systems|The requirements of Section 140.5 without solar water heating requirements.|The requirements of Section 140.5 without solar water heating requirements.| |Roofing products|The requirements of Section 141.0(b)2B.|The requirements of Section 141.0(b)2B.| |Lighting system|The requirements of Sections 141.0(b)2F through 141.0(b)2K.|The requirements of Sections 141.0(b)2F through 141.0(b)2K.| |All other measures|The proposed efficiency levels.|The proposed efficiency levels.|

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

TABLE 141.0-F—CONTROL REQUIREMENTS FOR INDOOR LIGHTING SYSTEM ALTERATIONS	Col2	Col3	Col4
CONTROL SPECIFICATIONS	CONTROL SPECIFICATIONS	PROJECTS COMPLYING WITH SECTION 141.0(B)2Ii	PROJECTS COMPLYING WITH SECTION 141.0(B)2Iii OR 141.0(B)2Iiii
Manual Area Controls	130.1(a)1	Required	Required
Manual Area Controls	130.1(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.

§ 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.
§ 0.20 High 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
§ 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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§ 150.1 High relevance — show source text

N. Exterior doors. Alterations that add exterior door area shall meet the U -factor requirement of Section 150.1(c)5. 2. Performance approach. The energy budget for alterations is expressed in terms of long-term system cost (LSC), and the altered component(s) and any newly installed equipment serving the alteration shall meet the applicable requirements of Subsections A, B, and C below. A. The altered components shall meet the applicable requirements of Sections 110.0 through 110.9, Sections 150.0(a) through (l), Sections 150.0(m)1 through 150.0 (m)10, and Sections 150.0(p) through (q). Entirely new or complete replacement mechanical ventilation systems, as these terms are used in Section 150.2(b)1L, shall comply with the requirements in Section 150.2(b)1L. Altered mechanical ventilation systems shall comply with the requirements of Section 150.2(b)1M. Entirely new or complete replacement space-conditioning systems, and entirely new or complete replacement duct systems, as these terms are used in Sections 150.2(b)1C and 150.2(b)1Diia, shall comply with the requirements of Sections 150.0(m)12 and 150.0(m)13. B. The standard design for an altered component shall be the higher efficiency of existing conditions or the requirements stated in Table 150.2-G. For components not being altered, the standard design shall be based on the existing conditions. When the third party verification option is specified as a requirement, all components proposed for alteration for which the additional credit is taken must be verified by a certified ECC-Rater.

TABLE 150.2-G—STANDARD DESIGN FOR AN ALTERED COMPONENT	Col2	Col3
ALTERED COMPONENT	STANDARD DESIGN WITHOUT THIRD PARTY VERIFICATION OF EXISTING CONDITIONS SHALL BE BASED ON	STANDARD DESIGN WITH THIRD-PARTY VERIFICATION OF EXISTING CONDITIONS SHALL BE BASED ON
Ceiling insulation, wall insulation, and raised-floor insulation	The requirements of Sections 150.0(a), (c), and (d).	The existing insulation_R_-value.
Fenestration	The requirements of Section 150.1(c)3A.	The existing fenestration_U_-factor and SHGC values as verified.
Window film	The requirements of Section 150.1(c)3A.	The existing fenestration in the alteration shall be based on Tables 110.6-A and 110.6-B.
Doors	The_U_-factor of 0.20. 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.

§ 141.0 High relevance — show source text
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.

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

(d) Alternate method of compliance. Any addition, alteration or repair may comply with the requirements of Title 24, Part 6 by meeting the applicable 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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NONRESIDENTIAL AND HOTEL/MOTEL OCCUPANCIES— ADDITIONS, ALTERATIONS AND REPAIRS

SECTION 141.1—REQUIREMENTS FOR COVERED PROCESSES IN ADDITIONS, ALTERATIONS TO EXISTING NONRESIDENTIAL AND HOTEL/MOTEL BUILDINGS

Covered processes in additions or alterations to existing buildings that will be nonresidential and hotel/motel occupancies shall comply with the applicable Subsections of Section 120.6 and 140.9.

(a) Lab and Process Facility Exhaust Systems. Additions and alterations to existing laboratories and factories shall meet the requirements of Section 140.9(c).

(b) Computer Rooms. All newly installed computer room cooling systems and uninterruptible power supply systems in additions/alterations shall meet the requirements of Sections 120.6(j), 140.9(a)2 and 140.9(a)4 and comply with Item 1 below.
CRC § 301 High relevance — show source text
This change expands the current process from two independent 1-year cycles to a single continuous 3year cycle. There will be two groups of code development committees and they will meet in separate years. The current groups will be reworked. With the energy provisions of the International Energy Conservation Code ® (IECC®) and Chapter 11 of the International Residential Code ® (IRC®) now moved to the Code Council’s Standards Development Process, the reduced volume of code changes will be distributed between Groups A and B.

Code change proposals submitted for code sections that have a letter designation in front of them will be heard by the respective committee responsible for such code sections. Because different committees hold Committee Action Hearings in different years, proposals for most codes will be heard by committees in both the 2024 (Group A) and the 2025 (Group B) code development cycles. It is very important that anyone submitting code change proposals understands which code development committee is responsible for the section of the code that is the subject of the code change proposal.

Please visit the ICC website at iccsafe.org/products-and-services/i-codes/code-development/current-code-development-cycle for further information on the Code Development Committee responsibilities as it becomes available.

Coordination of the I-Codes

The coordination of technical provisions allows the I-Codes to be used as a complete set of complementary documents. Individual codes can also be used in subsets or as stand-alone documents. Some technical provisions that are relevant to more than one subject area are duplicated in multiple model codes.

INTRODUCTION TO THE INTERNATIONAL EXISTING BUILDING CODE

The IEBC establishes minimum requirements for existing buildings using prescriptive and performance-related provisions. It is founded on broad-based principles intended to encourage the use and reuse of existing buildings while requiring reasonable upgrades and improvements.

The IEBC is a model code in the International Code family of codes intended to provide requirements for repair and alternative approaches for alterations, changes of occupancy and additions to existing buildings. A large number of existing buildings and structures do not comply with the current building code requirements for new construction. Although many of these buildings are potentially salvageable, rehabilitation is often cost-prohibitive because compliance with all the requirements for new construction could require extensive changes that go well beyond the value of the building or the original scope of the alteration. At the same time, it is necessary to regulate construction in existing buildings that undergo additions, alterations, extensive repairs or change of occupancy. Such activity represents an opportunity to ensure that new construction complies with the current building codes and that existing conditions are maintained, at a minimum, to their current level of compliance or are improved as required to meet basic safety levels. To accomplish this objective, and to make the alteration process easier, this code allows for options for controlled departure from full compliance with the International Codes dealing with new construction, while maintaining basic levels for fire safety, structural and life safety features of the rehabilitated building.

This code provides three main options for a designer in dealing with alterations of existing buildings. These are laid out in Section 301 of this code:

Option 1: Work for alteration, change of occupancy or addition of all existing buildings shall be done in accordance with the Prescriptive Compliance Method given in Chapter 5. It should be noted that this method originates from the former Chapter 34 of the IBC (2012 and earlier editions).

Option 2: Work for alteration, change of occupancy or addition of all existing buildings shall be done in accordance with the Work Area C

§ 10-109 High relevance — show source text

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

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

TABLE P4-A ADOPTION TABLE	Col2	Col3
CODE SECTION		AGENCY
Adopt entire Chapter as amended (amended sections listed below)1		CEC
601.0		X
602.0		X
603.0		X
604.0		X
605.0		X
1. Adopted by reference for Occupancies A, B, E, F, H, M, R, S, and U; see Sections 110.8(d)3, 120.4 and 150.0(m).	1. Adopted by reference for Occupancies A, B, E, F, H, M, R, S, and U; see Sections 110.8(d)3, 120.4 and 150.0(m).	1. Adopted by reference for Occupancies A, B, E, F, H, M, R, S, and U; see Sections 110.8(d)3, 120.4 and 150.0(m).

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10 MULTIFAMILY BUILDINGS—MANDATORY REQUIREMENTS

SECTION 160.0—GENERAL

§ 1.10.1 High relevance — show source text
Chapter 5A Prescriptive Compliance Method.

Chapter 5A provides details for the prescriptive compliance method for alteration, addition and change of occupancy of existing build- ings and structures regulated by the Department of Health Care Access and Information/Office of Statewide Hospital Planning and Development, which include hospitals and correctional treatment centers (applications listed in Sections 1.10.1 (OSHPD 1).

Chapter 6 Classification of Work.

Chapter 6 provides an overview of the Work Area Method and defines the different classifications of work including alterations, change of occupancy, additions and historic buildings. Detailed requirements for all of these are given in subsequent Chapters 7 through 11.

Chapter 7 Alterations—Level 1.

Chapter 7 provides the technical requirements for those existing buildings that undergo Level 1 alterations as described in Section 602, which includes replacement or covering of existing materials, elements, equipment or fixtures using new materials for the same purpose. This chapter is distinguished from Chapters 8 and 9 by only involving replacement of building components with new components with no reconfiguration of space.

Chapter 8 Alterations—Level 2.

A Level 2 alteration is an alteration involving space reconfiguration that could be up to and including 50 percent of the area of the building or addition of a new building system. Level 2 alterations also include the extension or addition of any system or equipment. The purpose of Chapter 8 is to provide detailed requirements and provisions to identify the required improvements in the existing building elements, means of egress, fire protection, structural systems, energy efficiency, and other building systems include electrical, mechanical and plumbing when a building is being altered.

Chapter 9 Alterations—Level 3.

Chapter 9 provides the technical requirements for those existing buildings that undergo Level 3 alterations. Level 3 alterations are those involving alterations that cover 50 percent of the aggregate area of the building. Under certain situations, this chapter also intends to improve the safety of certain building features beyond the work area and in other parts of the building where no alteration work might be taking place.

Chapter 10 Change of Occupancy.

The purpose of Chapter 10 is to address existing buildings that are subject to a change of occupancy. This chapter is an assembly of requirements to upgrade safety without having to comply fully as a new building. A change of occupancy classification is considered a change of occupancy, however, it will involve a higher level of regulation since the use of the building has made a more significant change.

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Chapter 11 Additions.

Chapter 11 provides the requirements for additions, which are considered new construction. The requirements focus on safely integrating the addition with the existing building. This includes issues such as limiting the overall height and area of the building where the addition is not separated by a fire wall.

Chapter 12 Historic Buildings —Reserved

Chapter 12 is not adopted by the State of California. Historic buildings and structures shall comply with Part 8, Title 24, California Code of Regulations.

Chapter 13 Performance Compliance Methods.

Chapter 13 allows for existing buildings to be evaluated to show that alterations or a change of occupancy, while not meeting new construction requirements, will provide a level of safety to demonstrate compliance. Provisions are based on a numerical scoring system involving 21 safety parameters where, when evaluated, such buildings must meet a minimum overall safety score.
§ 1.10.1 High relevance — show source text
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Chapter 3 Provisions for All Compliance Methods.

Chapter 3 guides the use of the three compliance methods of the CEBC and provides requirements that apply globally. The globally applicable requirement include general requirements related to buildings materials and other applicable codes, storm shelters, structural loads, in-situ load tests, accessibility, smoke alarms, carbon monoxide detection and exterior wall coverings.

Chapter 3A Provisions for All Compliance Methods.

Chapter 3A controls the compliance options for alteration, repair, addition, evaluation and change of occupancy of existing structures regulated by the Department of Health Care Access and Information/Office of Statewide Hospital Planning and Development, which include hospitals and correctional treatment centers (applications listed in Sections 1.10.1 (OSHPD 1).

Chapter 4 Repairs.

Chapter 4, a chapter independent of the three compliance methods, governs the repair of existing buildings. The provisions define conditions under which repairs may be made using materials and methods like those of the original construction or the extent to which repairs must comply with requirements for new buildings.

Chapter 4A Repairs.

Chapter 4A governs the repair of existing buildings regulated by the Department of Health Care Access and Information/Office of State- wide Hospital Planning and Development, which include hospitals and correctional treatment centers (applications listed in Sections 1.10.1 (OSHPD 1).

Chapter 5 Prescriptive Compliance Method.

Chapter 5 provides one of the three main options of compliance available in the CEBC for buildings and structures undergoing alteration, addition or change of occupancy. The base requirements are more administrative in nature. The structural triggers for upgrades are consistent with the Work Area Method.

Chapter 5A Prescriptive Compliance Method.

Chapter 5A provides details for the prescriptive compliance method for alteration, addition and change of occupancy of existing build- ings and structures regulated by the Department of Health Care Access and Information/Office of Statewide Hospital Planning and Development, which include hospitals and correctional treatment centers (applications listed in Sections 1.10.1 (OSHPD 1).

Chapter 6 Classification of Work.

Chapter 6 provides an overview of the Work Area Method and defines the different classifications of work including alterations, change of occupancy, additions and historic buildings. Detailed requirements for all of these are given in subsequent Chapters 7 through 11.

Chapter 7 Alterations—Level 1.

Chapter 7 provides the technical requirements for those existing buildings that undergo Level 1 alterations as described in Section 602, which includes replacement or covering of existing materials, elements, equipment or fixtures using new materials for the same purpose. This chapter is distinguished from Chapters 8 and 9 by only involving replacement of building components with new components with no reconfiguration of space.

Chapter 8 Alterations—Level 2.

A Level 2 alteration is an alteration involving space reconfiguration that could be up to and including 50 percent of the area of the building or addition of a new building system. Level 2 alterations also include the extension or addition of any system or equipment. The purpose of Chapter 8 is to provide detailed requirements and provisions to identify the required improvements in the existing building elements, means of egress, fire protection, structural systems, energy efficiency, and other building systems include electrical, mechanical and plumbing when a building is being altered.

Chapter 9 Alterations—Level 3.
§ 204.1 High relevance — show source text
** Buildings complying with the second level of advanced energy efficiency shall have an Energy Budget that is no greater than indicated below, depending on building type and the type of energy systems included in the building project. If the newly constructed building or addition does not include indoor lighting or mechanical systems, then no additional performance requirements above Title 24, Part 6 are required.
1. For nonresidential building projects that include indoor lighting or mechanical systems, but not both: No greater than 90 percent of the Title 24, Part 6, Energy Budget for the Standard Design Building as calculated by compliance software certified by the Energy Commission.
2. For nonresidential building projects that include indoor lighting and mechanical systems: No greater than 85 percent of the Title 24, Part 6, Energy Budget for the Standard Design Building as calculated by compliance software certified by the Energy Commission.
3. For high-rise residential and hotel/motel building projects: No greater than 95 percent of the Title 24, Part 6, Energy Budget for the Standard Design Building as calculated by compliance software certified by the Energy Commission.
Note: For Energy Budget calculations, high-rise residential and hotel/motel buildings are considered nonresidential buildings.

SECTION A5.204—MANDATORY REQUIREMENTS FOR ALTERATIONS TO EXISTING BUILDINGS

A5.204.1 Energy efficiency . Alterations to existing nonresidential buildings shall comply with Section A5.204.1.1.

A5.204.1.1 Altered pool and/or spa heating for existing nonresidential buildings . Alteration of existing nonresidential pool and/or spa heating system shall meet the following.

Heating source sizing. Heating systems or equipment for pools or spas shall meet one of the sizing requirements of Items 1 through 5 below:
1. Solar pool heating system with a solar collector surface area that is equivalent to 65 percent or greater of the surface areas of the pool or spa or a combination of both respectively; or
2. A heat pump pool heater as the primary heating system that meets the sizing requirements of Reference Joint Appendix JA16.3. The control for the heat pump pool heater shall meet the requirements specified in Section 110.4(d). The supplementary heater can be of any energy source; or
3. A heating system that derives at least 60 percent of the annual heating energy from on-site renewable energy or on-site recovered energy; or
4. A combination of a solar pool heating system and heat pump pool heater without any additional supplementary heater;
or
1. A pool heating system determined by the Energy Commission Executive Director to use no more energy than the systems specified in Item 1, 2, 3, or 4 above.
Exception 1 to A5.204.1.1: Portable electric spas compliant with 20 CCR, Section 1605.3(g)(7) of the Appliance Efficiency Regulations.

Exception 2 to A5.204.1.1: A pool or spa that is heated solely by a solar pool heating system without any supplementary heater.

Exception 3 to A5.204.1.1: An existing building with inadequate Solar Access Roof Area (SARA) as specified in Section 140.10(a) for a solar pool heating system to be installed.

Exception 4 to A5.204.1.1: Heating systems which are used exclusively for permanent spa applications in existing buildings with gas availability.

SECTION A5.211—RESERVED

SECTION A5.212—ELEVATORS, ESCALATORS AND OTHER EQUIPMENT
§ 10-109 Medium 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.
§ 10-109 Medium relevance — show source text
PROPOSED DESIGN BUILDING is a building that is simulated by Commission-approved compliance software to determine the energy consumption resulting from all of the characteristics and energy consuming features that are actually proposed for a building, as specified by Section 10-109(c) and Section 10-116.

PUBLIC AREAS are spaces generally open to the public at large, customers or congregation members, or similar spaces where occupants need to be prevented from controlling lights for safety, security or business reasons. R -VALUE is the measure of the thermal resistance of insulation or any material or building component expressed in ft [2] -hr-°F/Btu.

RADIANT BARRIER is a highly reflective, low emitting material installed at the underside surface of the roof deck and the inside surface of gable ends or other exterior vertical surfaces in attics to reduce solar heat gain.

RAISED FLOOR is a floor (partition) over a crawl space, or an unconditioned space, or ambient air.

READILY ACCESSIBLE is capable of being reached quickly for operation, repair or inspection, without requiring climbing or removing obstacles, or resorting to access equipment.

RECOOL is the cooling of air that has been previously heated by space-conditioning equipment or systems serving the same building.

RECOVERED ENERGY is energy used in a building that (1) is recovered from space conditioning, service water heating, lighting, or process equipment after the energy has performed its original function; (2) provides space conditioning, service water heating, or lighting; and (3) would otherwise be wasted.

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ALL OCCUPANCIES—GENERAL PROVISIONS

RECOVERED ENERGY, ON-SITE is recovered energy that is captured at the building site.

REFERENCE APPENDICES is the support document for the Building Energy Efficiency Standards. The document consists of three sections: the Reference Joint Appendices (JA), the Reference Residential Appendices (RA) and the Reference Nonresidential Appendices (NA).

REFLECTANCE, SOLAR is the ratio of the reflected solar flux to the incident solar flux.

REFRIGERATED CASE is a manufactured commercial refrigerator or freezer, including but not limited to display cases, reach-in cabinets, meat cases, and frozen food and soda fountain units.

REFRIGERATED SPACE is a space constructed for storage or handling of products, where mechanical refrigeration is used to maintain the space temperature at 55°F or less.

REFRIGERATED WAREHOUSE is a building or a space greater than or equal to 3,000 square feet constructed for storage or handling of products, where mechanical refrigeration is used to maintain the space temperature at 55°F or less.

REHEAT is the heating of air that has been previously cooled by cooling equipment or supplied by an economizer.

RELOCATABLE PUBLIC SCHOOL BUILDING is a relocatable building as defined by Title 24, Part 1, Section 4-314, which is subject to Title 24, Part 1, Chapter 4, Group 1.

REPAIR is the reconstruction or renewal for the purpose of maintenance of any component, system or equipment of an existing building. Repairs shall not increase the preexisting energy consumption of the repaired component, system or equipment. Replacement of any component, system or equipment for which there are requirements in the Standards is considered an alteration and not a repair.
§ 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.
§ 52.2 Medium relevance — show source text
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ALL OCCUPANCIES—GENERAL PROVISIONS

or heat recovery ventilation (HRV) are not considered mechanical cooling. In nonresidential, multifamily buildings and hotel/motel buildings, cooling of a space by direct or indirect evaporation of water alone is not considered mechanical cooling.

MECHANICAL HEATING is raising the temperature within a space using electric resistance heaters, fossil fuel burners, heat pumps or other systems that require energy to directly condition the space. Systems that only use solar energy or heat recovery as the heat source are not mechanical heating systems.

MERV is the minimum efficiency reporting value as determined by ASHRAE Standard 52.2 Method of Testing General Ventilation AirCleaning Devices for Removal Efficiency by Particle Size.

METAL BUILDING is a complete integrated set of mutually dependent components and assemblies that form a building, which consists of a steel-framed superstructure and metal skin. This does not include structural glass or metal panels such as in a curtainwall system.

MICROCHANNEL CONDENSER is an air-cooled condenser for refrigeration systems which utilizes multiple small parallel gas flow passages in a flat configuration with fin surfaces bonded between the parallel gas passages.

MINISPLIT AIR CONDITIONERS AND HEAT PUMPS are air conditioner or heat pump systems that have a single outdoor section and one or more indoor sections. The indoor sections cycle on and off in unison in response to a single indoor thermostat.

MODELING ASSUMPTIONS are the conditions (such as weather conditions, thermostat settings and schedules, internal gain schedules, etc.) that are used for calculating a building’s annual energy consumption as specified in Section 10-109(c) and Section 10-116.

MULTIFAMILY BUILDING is any of the following:

A building of Occupancy Group R-2, other than a hotel/motel building or timeshare property,

A building of Occupancy Group R-3 that is a nontransient congregate residence, other than boarding houses of more than 6 guests and alcohol or drug abuse recovery homes of more than 6 guests, or

A building of Occupancy Group R-4.

MULTIPLE-SPLIT AIR CONDITIONERS AND HEAT PUMPS are air conditioner or heat pump systems that have two or more indoor sections. The indoor sections operate independently and can be used to condition multiple zones in response to multiple indoor thermostats.

MULTIPLE ZONE SYSTEM (or multi-zone system) is a space conditioning system that conditions more than one space conditioning zone, each of which has one or more devices (such as dampers, cooling coils and heating coils) that regulate airflow, cooling or heating capacity to the zone.

NATURAL GAS AVAILABILITY. For newly constructed buildings, natural gas is available if a gas service line can be connected to the site without a gas main extension. For addition and alteration, natural gas is available if a gas service line is connected to the existing building.

NEEA is the Northwest Energy Efficiency Alliance.

NEEA ADVANCED WATER HEATER SPECIFICATION is the Northwest Energy Efficiency Alliance (NEEA) specification version 8.1, effective date July 15, 2024, for heat pump water heaters.

NET EXHAUST FLOW RATE is the exhaust flow rate for a hood, minus any internal discharge makeup air flow rate.
§ 130.5 Medium relevance — show source text
Exception 2 to Section 130.5(d): Receptacles in healthcare facilities.

(e) Demand responsive controls and equipment. See Section 110.12 for requirements for demand responsive controls and equipment, including demand responsive controls for controlled receptacles.

Note: Definitions of terms and phrases in Section 130.5 are determined as specified in Section 100.1(b). Terms and phrases not found in Section 100.1(b) shall be defined as specified in Title 24, Part 3, Article 100 of the California Electrical Code.

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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5 NONRESIDENTIAL AND HOTEL/MOTEL OCCUPANCIES—

PERFORMANCE AND PRESCRIPTIVE COMPLIANCE APPROACHES FOR ACHIEVING ENERGY EFFICIENCY

SECTION 140.0—PERFORMANCE AND PRESCRIPTIVE COMPLIANCE APPROACHES

Nonresidential and hotel/motel buildings shall comply with all of the following: (a) The requirements of Sections 100.0 through 110.12 applicable to the building project (mandatory measures for all buildings). (b) The requirements of Sections 120.0 through 130.5 (mandatory measures for nonresidential and hotel/motel buildings). (c) Either the performance compliance approach (energy budgets) specified in Section 140.1 or the prescriptive compliance approach specified in Section 140.2 for the climate zone in which the building will be located. Climate zones are shown in Figure 100.1-A.

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.
§ 2.5 Medium relevance — show source text
iv. Attic ventilation shall comply with the California Residential Code, Title 24, Part 2.5, Section R806. Exception 1 to Section 150.2(b)1J: Dwelling units with at least R-38 existing insulation installed at the ceiling level. Exception 2 to Section 150.2(b)1J: Dwelling units where the alteration would directly cause the disturbance of asbestos.

Exception 3 to Section 150.2(b)1J: Dwelling units with knob and tube wiring located in the vented attic.

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

Exception 4 to Section 150.2(b)1J: Where the accessible space in the attic is not large enough to accommodate the required R -value, the entire accessible space shall be filled with insulation provided such installation does not violate Section 806.3 of Title 24, Part 2.5. Exception 5 to Section 150.2(b)1J: Where the attic space above the altered dwelling unit is shared with other dwelling units and the requirements of Section 150.2(b)1J are not triggered for the other dwelling units. K. Lighting. The altered lighting system shall meet the lighting requirements of Section 150.0(k). The altered luminaires shall meet the luminaire efficacy requirements of Section 150.0(k). Where existing screw-base sockets are present in ceiling-recessed luminaires, removal of these sockets is not required provided that new JA8-compliant trim kits or lamps designed for use with recessed downlights or luminaires are installed. L. Mechanical ventilation for indoor air quality—entirely new or complete replacement ventilation systems. Entirely new or complete replacement ventilation systems shall comply with all applicable requirements in Section 150.0(o). An entirely new or complete replacement ventilation system includes a new ventilation fan component and an entirely new duct system. An entirely new or complete replacement duct system is constructed of at least 75 percent new duct material, and up to 25 percent may consist of reused parts from the dwelling unit's existing duct system, including but not limited to registers, grilles, boots, air filtration devices and duct material, if the reused parts are accessible and can be sealed to prevent leakage. M. Mechanical ventilation for indoor air quality—altered ventilation systems. Altered ventilation system components or newly installed ventilation equipment serving the alteration shall comply with Section 150.0(o) as applicable subject to the requirements specified in Subsections i and ii below. i. Whole-dwelling unit mechanical ventilation. a. Whole-dwelling unit airflow. If the whole-dwelling ventilation fan is altered or replaced, then one of the following Subsections 1 or 2 shall be used for compliance as applicable.
1. Dwellings that were required by a previous building permit to comply with the whole-dwelling unit airflow requirements in Section 150.0(o) shall meet or exceed the whole-dwelling unit mechanical ventilation airflow specified in Section 150.0(o)1C, 150.0(o)1E or 150.0(o)1F as confirmed through field verification and diagnostic testing in accordance with the applicable procedures specified in Reference Residential Appendix RA3.7.

Frequently asked questions

How do I document an existing efficiency level?

Document the existing efficiency using nameplate data or measured field data where available. If nameplate data is missing, follow the Part‑1 modeling rules in § 10‑109(c) and § 10‑116 for allowable defaults or estimation procedures; §180.2 tells you to rely on those Part‑1 rules.

If the existing equipment is better than the code prescriptive minimum, which do I use for the standard design?

Use the higher efficiency of the existing equipment or the prescriptive requirement — whichever is more efficient becomes the standard design for that altered component, per § 180.2.

Do I need third‑party verification to use the existing values?

Not always, but if you elect the third‑party verification option (or the jurisdiction requires it), existing efficiencies that receive credit must be verified (for example, by an ECC‑Rater) as described in the alteration rules. § 180.2 notes the verification requirement.

How should I model components not being altered?

Model unaltered components using their unaltered existing conditions so that the standard and proposed designs for those components are identical, per § 180.2.

Where can I find the exact procedures for substituting missing nameplate data?

The code directs you to Part‑1 modeling rules § 10‑109(c) and § 10‑116 for exact procedures. The files I have reference those sections but do not include their full text, so check Title 24, Part 1 for the precise substitution and default rules.

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