CBC · California Building Code

Where are the residential voluntary energy measures (Appendix A4)?

Appendix A4, Division A4.2 contains California’s voluntary residential energy measures (performance path based on the Hourly Source Energy Rating/EDR plus prerequisite measures). These provisions are guidance unless a city or county adopts them locally — and local adoption requires California Energy Commission/CBSC filings per § A4.201.1 .

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Last reviewed: July 5, 2026

What the code requires

Appendix A4 contains California’s voluntary residential green-building measures; Division A4.2 is the Energy Efficiency portion that describes the voluntary energy measures and a performance approach for newly constructed residential buildings. These provisions are voluntary for the State but may be adopted and enforced locally only after the local jurisdiction obtains the California Energy Commission approval and follows the adoption steps in § A4.201.1 .

Requirements in detail

Scope and relationship to the mandatory Energy Code

The voluntary measures in Division A4.2 are expressly intended to encourage exemplary energy performance and are not a replacement for the mandatory Title 24, Part 6 Energy Code. § A4.201.1 explains that the Energy Commission continues to adopt mandatory standards in Title 24, Part 6; Appendix A4’s provisions are voluntary unless a local jurisdiction elects to adopt them and obtains the required approvals (§ A4.201.1) .

Performance approach and required components

Division A4.2 implements a performance-based path for newly constructed residential buildings:
- § A4.203.1 requires use of an Hourly Source Energy Rating (EDR) computed by Energy Commission–compliant software and reduction of the required EDR by the compliance margins listed in Table A4.203.1.1 (§ A4.203.1.1 and Table A4.203.1.1) .
- § A4.203.1.2 lists prerequisite options: at least two of the measures in A4.203.1.2.1 through A4.203.1.2.8 must be met (examples: roof deck insulation or ducts in conditioned space; high‑performance walls; compact hot water distribution; drain‑water heat recovery; high performance vertical fenestration; heat‑pump water‑heater demand management; battery storage controls; heat‑pump space and water heating) (§ A4.203.1.2) .
- § A4.203.1.3 requires consultation with the local electric service provider when jurisdictions propose reduced EDR targets that rely on PV systems larger than the Energy Code baseline (§ A4.203.1.3) .

How Appendix A4 ties into the voluntary tiers (Tier 1 / Tier 2)

The Tier structure in Division A4.6 requires compliance with mandatory Chapter 4 measures plus specific prerequisite and elective measures drawn from Appendix A4. For example, Tier 1 and Tier 2 list required energy items that point back to Division A4.2 sections (see A4.601.4.2 for Tier 1 and A4.601.5.2 for Tier 2) (§ A4.601.4.2; § A4.601.5.2) .

Decision‑relevant summary table

Decision dimension	What to check / value	Code reference
Is the measure mandatory at state level?	No — Appendix A4 measures are voluntary state guidance; become mandatory only if adopted locally with required approvals	§ A4.201.1
Where are the energy rules for residential voluntary measures?	Division A4.2 (Sections A4.201 → A4.204 and A4.203 performance approach)	§ A4.201.1; § A4.203.1; § A4.203.1.1; Table A4.203.1.1
Performance path requirement	Compute hourly Source Energy Rating (EDR) with compliant software and meet the reduced EDR per Table A4.203.1.1	§ A4.203.1; § A4.203.1.1
Required prerequisites	At least two measures from A4.203.1.2.1–A4.203.1.2.8 (listed in § A4.203.1.2)	§ A4.203.1.2
Local utility consultation when using PV to lower EDR	Local jurisdictions must consult the local electric service provider if reduced EDR relies on PV larger than Title 24 Part 6 baseline	§ A4.203.1.3
How tiers use Division A4.2	Tier checklists reference Division A4.2 energy sections as prerequisites/electives for Tier 1 and Tier 2	§ A4.601.4.2; § A4.601.5.2

Exceptions & special cases

Local adoption required: Appendix A4 energy measures remain voluntary unless the local jurisdiction adopts them as mandatory and secures California Energy Commission approval and follow‑up filing as described in § A4.201.1 .
PV sizing/EDR reductions: If a jurisdiction reduces EDR targets based on larger-than‑baseline PV systems, the jurisdiction must consult the local electric service provider so the required PV sizing will be acceptable (§ A4.203.1.3) .
Specific equipment/system exceptions: Some Division A4 energy sections include their own exceptions (for example, certain pool‑heating system exceptions are listed under A4.204.1.2) — consult the individual energy subsections for the exceptions that apply to particular systems (§ A4.204.1.2) .

Common mistakes

Treating Appendix A4 as automatically mandatory statewide. Appendix A4 is voluntary; only local adoption (with Energy Commission/CBSC filings where required) makes measures mandatory locally (§ A4.201.1; § A4.601.1) .
Omitting the prerequisite measures when using the performance route. The performance approach in § A4.203.1 requires meeting the EDR reductions in Table A4.203.1.1 and also satisfying the prerequisite options in § A4.203.1.2 (minimum of two listed measures) .
Failing to consult the electric service provider before adopting lower EDR targets that rely on oversized PV systems — § A4.203.1.3 requires that consultation to ensure utility acceptance of the PV sizing .
Confusing Title 24 Part 6 mandatory Energy Code compliance with Appendix A4 voluntary measures. The Energy Commission’s mandatory standards remain in Title 24, Part 6; Appendix A4 is distinct and voluntary (see § A4.201.1) .

Worked example — applying the Division A4.2 performance path (process with counts)

Scenario: A builder is planning a newly constructed low‑rise residential project and wants to follow Appendix A4’s performance approach to achieve a voluntary Tier goal.

Steps the builder must follow (grounded to the code sections):

Use Energy Commission–compliant modeling software to compute the building’s Hourly Source Energy Rating (EDR) per § A4.203.1 and § A4.203.1.1 .
Apply the compliance margin from Table A4.203.1.1 (the building’s modeled EDR must meet the reduced target established in that table) — consult Table A4.203.1.1 as part of § A4.203.1.1 for the exact margin values (§ A4.203.1.1; Table A4.203.1.1) . (Note: the numeric margins themselves are published in Table A4.203.1.1; that table’s numeric values must be read directly from the table in Division A4.2.)
Meet prerequisite measures: select and implement at least two of the measures listed in § A4.203.1.2 (for example, install roof‑deck insulation and provide high‑performance walls) — § A4.203.1.2 requires a minimum of two listed measures .
If the local jurisdiction plans to accept a lower EDR by relying on PV systems larger than the Title 24 baseline, the jurisdiction must consult the local electric service provider per § A4.203.1.3 before finalizing the requirement .
If the builder is seeking a Tier (Tier 1 or Tier 2) designation, verify the applicable Tier prerequisites/electives in § A4.601.4.2 (Tier 1) or § A4.601.5.2 (Tier 2), because the Tier checklists point back to Division A4.2 energy sections as required elements § A4.601.4.2; § A4.601.5.2 .

Numbers illustrated (process counts that are in the code text and may be followed without inventing numeric EDR margins):

Minimum number of prerequisite measures to pick from A4.203.1.2: 2 measures (§ A4.203.1.2) .
Tier checklists require a specified number of elective measures (see A4.601.4.2 and A4.601.5.2 for the counts and which Divisions they must come from) (§ A4.601.4.2; § A4.601.5.2) .
For the exact EDR reduction percentages / numerical margins, consult Table A4.203.1.1 in Division A4.2; those numeric values are published in the table itself (§ A4.203.1.1; Table A4.203.1.1) .

If you need, I can extract and reproduce the numeric values from Table A4.203.1.1 and any other numeric tables from Division A4.2 (EDR margins, specific Tier elective counts, etc.) — say which table or section you'd like shown verbatim and I will retrieve it.

Related provisions

§ A4.201.1 — General scope and the voluntary / local adoption requirement .
§ A4.202 — Definitions used in Division A4.2 (see A4.202.1) .
§ A4.203.1 — Performance approach for newly constructed buildings (EDR requirement) .
§ A4.203.1.1 — Hourly Source Energy Rating (EDR) and Table A4.203.1.1 reference .
§ A4.203.1.2 — Prerequisite options (minimum two required) .
§ A4.203.1.3 — Consultation with local electric service provider for reduced EDR targets using oversized PV .
§ A4.204.* — Additional energy subsections (e.g., pool heating provisions and exceptions) — see § A4.204.1.2 for specific exceptions .
§ A4.601.4.2 and § A4.601.5.2 — Tier 1 and Tier 2 prerequisite and elective measure cross‑references to Division A4.2 .

Code references

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

CBC § 601.5.2 High relevance — show source text
A4.601.5.2 Prerequisite and elective measures for Tier 2. In addition to the mandatory measures, compliance with the following prerequisite and elective measures from Appendix A4 is also required to achieve Tier 2 status.
1. From Division A4.1, Planning and Design.
2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-21

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APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

1.1. Comply with the topsoil protection requirements for Tier 1 and Tier 2 in Section A4.106.2.3. 1.2. Comply with the 30 percent permeable paving requirements in Section A4.106.4. 1.3. Comply with the cool roof requirements in Section A4.106.5. 1.4. Comply with the Tier 2 electric vehicle (EV) charging requirements in Section A4.106.8. 1.5. Comply with at least four elective measures selected from Division A4.1. 2. From Division A4.2, Energy Efficiency. 2.1. For newly constructed low-rise residential buildings, comply with the energy efficiency requirements in Sections A4.203.1, A4.203.1.1, Table A4.203.1.1, A4.203.1.2 and A4.203.1.3.
1. From Division A4.3, Water Efficiency and Conservation. 3.1. Comply with at least three elective measures selected from Division A4.3.
2. From Division A4.4, Material Conservation and Resource Efficiency. 4.1. Comply with the 25 percent cement reduction requirements in Section A4.403.2. 4.2. Comply with the 15 percent recycled content requirements in Section A4.405.3.1. 4.3. Comply with the 75 percent reduction in construction waste in Section A4.408.1. 4.4. Comply with at least four elective measures selected from Division A4.4.
3. From Division A4.5, Environmental Quality. 5.1. Comply with the 100 percent resilient flooring systems requirements in Section A4.504.2. 5.2. Comply with the thermal insulation requirements for Tier 1 and Tier 2 in Section A4.504.3. 5.3. Comply with at least one elective measure selected from Division A4.5.
Note: The Residential Occupancies Application Checklist contained in Section A4.602 may be used to show which elective measures are selected.

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DIVISION A4.6 – TIER 1 AND TIER 2

SECTION A4.602 — RESIDENTIAL OCCUPANCIES APPLICATION CHECKLIST

CBC § 203.1.2.1 High relevance — show source text

In addition, a minimum of two of
the efficiency measures specified in Sections A4.203.1.2.1 through
A4.203.1.2.8 will be required to be met.
· Roof Deck Insulation or Ducts in Conditioned Space.
· High-performance Walls.
· Compact Hot Water Distribution System.
· Drain Water Heat Recovery.
· High Performance Vertical Fenestration.
· Heat Pump Water Heater Demand Management.
· Battery Storage System Controls.
· **Heat Pump Space and Water Heating.||2|2|||| |**A4.203.1.3 Consultation with local electric service provider.**Local
jurisdictions considering adoption of reduced EDR targets based on
using solar photovoltaic (PV) systems larger than required by the
California Energy Code shall consult with the local electric service
provider to ensure that that PV system sizing required to comply with
the EDR targets will be acceptable to the local electric service
provider.||2|2||||

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APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

SECTION A4.602—RESIDENTIAL OCCUPANCIES APPLICATION CHECKLIST—continued

FEATURE OR MEASURE	LEVELS APPLICANT TO SELECT ELECTIVE MEASURES	Col3	Col4	VERIFICATIONS ENFORCING AGENCY TO SPECIFY VERIFICATION METHOD	Col6	Col7
FEATURE OR MEASURE	Mandatory	Prerequisites and electives1	Prerequisites and electives1	Enforcing Agency  All	Installer or Designer  All	Third party  All
FEATURE OR MEASURE	Mandatory	Tier 1	Tier 2	Tier 2	Tier 2	Tier 2
WATER EFFICIENCY AND CONSERVATION
Indoor Water Use
4.303.1Plumbing fixtures (water closets and urinals) and fittings (showerheads, faucets and pre-rinse spray valves) installed in residential buildings shall comply with the prescriptive requirements of Sections 4.303.1.1 through 4.303.1.4.5.						
4.303.2 Submeters for multifamily building and dwelling units in **mixed-use residential/commercial buildings.

CBC § 3.1. High relevance — show source text
1. From Division A4.3, Water Efficiency and Conservation. 3.1. Comply with at least two elective measures selected from Division A4.3.
2. From Division A4.4, Material Conservation and Resource Efficiency. 4.1. Comply with the 20 percent cement reduction requirements in Section A4.403.2. 4.2. Comply with the 10 percent recycled content requirements in Section A4.405.3.1. 4.3. Comply with the 65 percent reduction in construction waste in Section A4.408.1. 4.4. Comply with at least two elective measures selected from Division A4.4.
3. From Division A4.5, Environmental Quality. 5.1. Comply with the 90 percent resilient flooring systems requirements in Section A4.504.2. 5.2. Comply with the thermal insulation requirements for Tier 1 in Section A4.504.3. 5.3. Comply with at least one elective measure selected from Division A4.5.
Note: The Residential Occupancies Application Checklist contained in Section A4.602 may be used to show which elective measures are selected.

A4.601.5 Tier 2. To achieve Tier 2 status a project must comply with the following.

Note: The measures necessary to achieve Tier 2 status are very stringent. Cities, counties, and cities and counties considering adoption of Tier 2 as mandatory should carefully consider the stringency of each measure and ensure that the measures are achievable in their location.

A4.601.5.1 Mandatory measures for Tier 2. The project shall meet or exceed all of the mandatory measures in Chapter 4, Divisions 4.1 through 4.5 and Chapter 7 as applicable.

A4.601.5.2 Prerequisite and elective measures for Tier 2. In addition to the mandatory measures, compliance with the following prerequisite and elective measures from Appendix A4 is also required to achieve Tier 2 status.
1. From Division A4.1, Planning and Design.
2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-21

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APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

1.1. Comply with the topsoil protection requirements for Tier 1 and Tier 2 in Section A4.106.2.3. 1.2. Comply with the 30 percent permeable paving requirements in Section A4.106.4. 1.3. Comply with the cool roof requirements in Section A4.106.5. 1.4. Comply with the Tier 2 electric vehicle (EV) charging requirements in Section A4.106.8. 1.5. Comply with at least four elective measures selected from Division A4.1. 2. From Division A4.2, Energy Efficiency. 2.1. For newly constructed low-rise residential buildings, comply with the energy efficiency requirements in Sections A4.203.1, A4.203.1.1, Table A4.203.1.1, A4.203.1.2 and A4.203.1.3.
1. From Division A4.3, Water Efficiency and Conservation. 3.1. Comply with at least three elective measures selected from Division A4.3.
2. From Division A4.4, Material Conservation and Resource Efficiency. 4.1.
CBC § 8-6 High relevance — show source text
. . . . . . . . . . . . . . . 8-6 Worksheet (WS-9) 5.409.2 and A5.409.2 Whole Building Life Cycle Assessment: . . . . . . . . . . . . . . . . 8-7 Construction Waste Management (CWM) Plan . . . . . . . . . . . 8-8 Construction Waste Management (CWM) Worksheet. . . . . . 8-9 Construction Waste Management (CWM) Acknowledgment. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10 Title 23, Waters, California Code of Regulations . . . . . . . . . 8-11 Commissioning Referenced Standards for Non-energy Systems. . . . . . . . . . . . . . . . . . . . . . . . . 8-13 IES TM-15-11 Table A-1, Table 130.2-A and Table 130.2-B Uplight and Glare Ratings Tables. . . . . . . . . . . . . . 8-40

APPENDIX A4 RESIDENTIAL

VOLUNTARY MEASURES. . . . . . . . . . . . . . . . . APPENDIX A4-3

A4.1 Planning and Design . . . . . . . . . . . . . . . . . APPENDIX A4-3 A4.2 Energy Efficiency . . . . . . . . . . . . . . . . . . . . APPENDIX A4-9 A4.3 Water Efficiency and Conservation . . . APPENDIX A4-13 A4.4 Material Conservation and Resource Efficiency . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX A4-15 A4.5 Environmental Quality . . . . . . . . . . . . . . APPENDIX A4-19 A4.6 Tier 1 and Tier 2 . . . . . . . . . . . . . . . . . . . . APPENDIX A4-21

Division A4.6—Residential Occupancies Application Checklist . . . . . . . . . . . . . APPENDIX A4-23 A4.7 Residential Model Ordinance . . . . . . . . . APPENDIX A4-31

APPENDIX A5 NONRESIDENTIAL

VOLUNTARY MEASURES. . . . . . . . . . . . . . . . . APPENDIX A5-3
CBC § 8-40 High relevance — show source text
. . . . . . . . . . . . . 8-40

APPENDIX A4 RESIDENTIAL

VOLUNTARY MEASURES. . . . . . . . . . . . . . . . . APPENDIX A4-3

A4.1 Planning and Design . . . . . . . . . . . . . . . . . APPENDIX A4-3 A4.2 Energy Efficiency . . . . . . . . . . . . . . . . . . . . APPENDIX A4-9 A4.3 Water Efficiency and Conservation . . . APPENDIX A4-13 A4.4 Material Conservation and Resource Efficiency . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX A4-15 A4.5 Environmental Quality . . . . . . . . . . . . . . APPENDIX A4-19 A4.6 Tier 1 and Tier 2 . . . . . . . . . . . . . . . . . . . . APPENDIX A4-21

Division A4.6—Residential Occupancies Application Checklist . . . . . . . . . . . . . APPENDIX A4-23 A4.7 Residential Model Ordinance . . . . . . . . . APPENDIX A4-31

APPENDIX A5 NONRESIDENTIAL

VOLUNTARY MEASURES. . . . . . . . . . . . . . . . . APPENDIX A5-3

A5.1 Planning and Design . . . . . . . . . . . . . . . . . APPENDIX A5-3 A5.2 Energy Efficiency . . . . . . . . . . . . . . . . . . . APPENDIX A5-13 A5.3 Water Efficiency and Conservation . . . APPENDIX A5-19 A5.4 Material Conservation and Resource Efficiency . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX A5-25 A5.5 Environmental Quality . . . . . . . . . . . . . . APPENDIX A5-35 A5.6 Voluntary Tiers . . . . . . . . . . . . . . . . . . . . . APPENDIX A5-41 A5.601 CALGren Tier 1 and Tier 2. . . . . . . . . . APPENDIX A5-41

A5.602 CALGreen Verification Guidelines Mandatory Measures Checklist . . . . . . . . . . . . . . . APPENDIX A5-44

A5.602.1 CALGreen Verification Guidelines

Tier 1 Checklist . . . . . . . . . . . . . . . . . APPENDIX A5-48

A5.602.2 CALGreen Verification Guidelines

Tier 2 Checklist . . . . . . . . . . . . . . . . . APPENDIX A5-55

APPENDIX A6 VOLUNTARY STANDARDS FOR HEALTH

CBC § 504.1 High relevance — show source text

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APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

SECTION A4.602—RESIDENTIAL OCCUPANCIES APPLICATION CHECKLIST—continued

FEATURE OR MEASURE	LEVELS APPLICANT TO SELECT ELECTIVE MEASURES	Col3	Col4	VERIFICATIONS ENFORCING AGENCY TO SPECIFY VERIFICATION METHOD	Col6	Col7
FEATURE OR MEASURE	Mandatory	Prerequisites and electives1	Prerequisites and electives1	Enforcing Agency  All	Installer or Designer  All	Third party  All
FEATURE OR MEASURE	Mandatory	Tier 1	Tier 2	Tier 2	Tier 2	Tier 2
A4.504.1Use composite wood products made with either California Air Resources Board approved no-added formaldehyde (NAF) resins or ultra-low emitting formaldehyde (ULEF) resins.						
A4.504.2Install VOC compliant resilient flooring systems. Tier 1. At least 90 percent of the resilient flooring installed shall comply. Tier 2.100 percent of the resilient flooring installed shall comply.		2	2			
A4.504.3Thermal insulation installed in the building shall meet the following requirements: Tier 1. Install thermal insulation in compliance with VOC limits. Tier 2. Install insulation which contains no-added formaldehyde (NAF) and is in compliance with Tier 1.		2	2			
Interior Moisture Control
4.505.2Vapor retarder and capillary break is installed at slab-on- grade foundations.						
4.505.3 Moisture content of building materials used in wall and floor framing is checked before enclosure.						
Indoor Air Quality and Exhaust
4.506.1 Each bathroom shall be provided with the following: 1. ENERGY STAR fans ducted to terminate outside the building. 2. Fans must be controlled by a humidity control (separate or built- in); OR functioning as a component of a whole-house ventilation system. 3.

CBC § 108.1 High relevance — show source text
108.1** Items in this section are necessary to address innovative
concepts or local environmental conditions.||||||| |Item 1|
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| |Item 3||||||| |ENERGY EFFICIENCY||||||| |General||||||| |4.201.1 Building meets or exceeds the requirements of the_California_
_Building Energy Efficiency Standards_3.||2|2|||| |Performance Approach for Newly
Constructed Buildings||||||| |**A4.203.1.1 Hourly Source Energy Rating (EDR1).**EDR1 ratings for
building design shall be computed by Energy Compliant software and
shall reduce the EDR1 required by the software by the compliance
margins specified in Table A4.203.1.1.||2|2|||| |**A4.203.1.2 Prerequisite options.In addition, a minimum of two of
the efficiency measures specified in Sections A4.203.1.2.1 through
A4.203.1.2.8 will be required to be met.
· Roof Deck Insulation or Ducts in Conditioned Space.
· High-performance Walls.
· Compact Hot Water Distribution System.
· Drain Water Heat Recovery.
· High Performance Vertical Fenestration.
· Heat Pump Water Heater Demand Management.
· Battery Storage System Controls.
· **Heat Pump Space and Water Heating.||2|2|||| |**A4.203.1.3 Consultation with local electric service provider.**Local
jurisdictions considering adoption of reduced EDR targets based on
using solar photovoltaic (PV) systems larger than required by the
California Energy Code shall consult with the local electric service
provider to ensure that that PV system sizing required to comply with
the EDR targets will be acceptable to the local electric service
provider.||2|2||||

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APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

SECTION A4.602—RESIDENTIAL OCCUPANCIES APPLICATION CHECKLIST—continued
CBC § 106.8.2.2 High relevance — show source text
Exception: Areas of parking facilities served by parking lifts, including but not limited to automated mechanicalaccess open parking garages as defined in the California Building Code ; or parking facilities otherwise incapable of supporting electric vehicle charging.

A4.106.8.2.2 Technical requirements. The EV spaces required by Section A4.106.8.2 shall be designed and constructed in accordance with Sections 4.106.4.2, 4.106.4.2.2.1.1, 4.106.4.2.2.1.2, and 4.106.4.2.5.

SECTION A4.107 (RESERVED)

SECTION A4.108 —INNOVATIVE CONCEPTS AND LOCAL ENVIRONMENTAL CONDITIONS

A4.108.1 Innovative concepts and local environmental conditions. The provisions of this code are not intended to prevent the use of any alternate material, appliance, installation, device, arrangement, method, design or method of construction not specifically prescribed by this code. This code does not limit the authority of city, county, or city and county government to make necessary changes to the provisions contained in this code pursuant to Section 101.7.1.

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APPENDIX A4-8 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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A4 RESIDENTIAL VOLUNTARY MEASURES

DIVISION A4.2 – ENERGY EFFICIENCY

SECTION A4.201—GENERAL

A4.201.1 Scope. For the purposes of mandatory energy efficiency standards in the California Building Standards Code (Title 24), the California Energy Commission will continue to adopt mandatory standards in the California Energy Code (Title 24, Part 6). It is the intent of these voluntary provisions to encourage local jurisdictions through codification to achieve exemplary performance in the area of building energy efficiency. Local jurisdictions adopting these voluntary provisions as mandatory local energy efficiency standards shall submit the required application and receive the required approval of the California Energy Commission in compliance with Title 24, Part 1, Section 10-106 prior to enforcement. Once the required filing has been verified and finding has been made by the Energy Commission, local jurisdictions shall file an ordinance expressly marking the local modification along with findings and receive the required acceptance from the California Building Standards Commission in compliance with Section 101.7 of this code, prior to enforcement. (Title 24, Part 1, Section 10-106 is available at https://www.energy.ca.gov/programs-and-topics/programs/build- ing-energy-efficiency-standards/2025-building-energy-efficiency

SECTION A4.202—DEFINITIONS

A4.202.1 Definitions. The following terms are defined in Chapter 2.

ENERGY BUDGET.

LONG-TERM SYSTEM COST (LSC).

RECOVERED ENERGY, ON-SITE.

SOLAR POOL HEATING SYSTEM.

SECTION A4.203—PERFORMANCE APPROACH FOR NEWLY CONSTRUCTED BUILDINGS
CBC § 101.7. Medium relevance — show source text
Green building measures listed in this table may be mandatory if adopted by a city, county, or city and county as specified in Section 101.7.
2. Required prerequisite for this Tier.
3. These measures are currently required elsewhere in statute or in regulation.|1. Green building measures listed in this table may be mandatory if adopted by a city, county, or city and county as specified in Section 101.7.
2. Required prerequisite for this Tier.
3. These measures are currently required elsewhere in statute or in regulation.|

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APPENDIX A4-30 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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DIVISION A4.7 – RESIDENTIAL MODEL ORDINANCE

A4.701.1 General. The voluntary measures of this code are designed and promulgated to be adopted by reference and made mandatory by local ordinance pursuant to Section 101.7. Jurisdictions wishing to adopt the voluntary provisions of this code as an enforceable regulation governing structures and premises should ensure that certain factual information is included in the adopting ordinance and that the measures are appropriate and achievable and are considered to be suitable as mandatory by the city, county, or city and county. The following sample adoption ordinance addresses several key elements of a code adoption ordinance, including the information required for insertion into the code text.

This code does not limit the authority of city, county, or city and county government to make necessary changes to the provisions contained in this code.

SAMPLE RESOLUTION FOR ADOPTION OF THE TIER 1 OR TIER 2 PROVISIONS OF THE CALIFORNIA GREEN BUILDING STANDARDS CODE WITH OR WITHOUT ADDITIONAL ITEMS NECESSARY TO ADDRESS INNOVATIVE CONCEPTS OR LOCAL ENVIRONMENTAL CONDITIONS.

ATTACHMENT___.

SAMPLE RESOLUTION ADOPTING THE CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDICES AS A MANDATORY REFERENCE STANDARD

CITY OF ________________________

RESOLUTION # __________________

RESOLUTION ADOPTING ENHANCED GREEN BUILDING MEASURES FOR NEW AND EXISTING RESIDENTIAL CONSTRUCTION.

WHEREAS, the City/County of ______’s (City or County) General Plan sets forth goals for preserving and improving the natural and built environment of the City/County, protecting the health of its residents and visitors, and fostering its economy; and

WHEREAS, green building is a holistic approach to design, construction and demolition that minimizes the building’s impact on the environment, the occupants and the community; and

WHEREAS, green buildings benefit building industry professionals, residents and communities by improving construction quality; increasing building durability; reducing utility, maintenance, water and energy costs; creating healthier homes; and enhancing comfort and livability; and

WHEREAS, the California Green Building Standards Code appendices have included voluntary tiers to provide a city, county, or city and county, building professionals, and the general public with a range of voluntary green building measures for builders to choose from when constructing homes in California; and
CBC § 506.1 Medium relevance — show source text
See California Department of Public Health’s website for certification programs and testing labs.

https://www.cdph.ca.gov/Programs/CCDPHP/DEODC/EHLB/IAQ/Pages/VOC.aspx

Tier 2. Install insulation which complies with Tier 1 plus does not contain any added formaldehyde.

Note: Documentation must be provided that verifies the materials are certified to meet the pollutant emission limits in this section.

SECTION A4.505—INTERIOR MOISTURE CONTROL (RESERVED)

SECTION A4.506—INDOOR AIR QUALITY AND EXHAUST

A4.506.1 Reserved.

A4.506.2 Construction filter. [HR] Provide filters on return air openings rated at MERV 8 or higher during construction.

A4.506.3 Direct-vent appliances. Direct-vent heating and cooling equipment shall be utilized if the equipment will be located in the conditioned space or install the space heating and water heating equipment in an isolated mechanical room.

2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-19

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APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

SECTION A4.507—ENVIRONMENTAL COMFORT (RESERVED)

SECTION A4.508—OUTDOOR AIR QUALITY (RESERVED)

SECTION A4.509 —INNOVATIVE CONCEPTS AND LOCAL ENVIRONMENTAL CONDITIONS

A4.509.1 Innovative concepts and local environmental conditions. The provisions of this code are not intended to prevent the use of any alternate material, appliance, installation, device, arrangement, method, design or method of construction not specifically prescribed by this code. This code does not limit the authority of city, county, or city and county government to make necessary changes to the provisions contained in this code pursuant to Section 101.7.1.

APPENDIX A4-20 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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A4 RESIDENTIAL VOLUNTARY MEASURES

DIVISION A4.6 – TIER I AND TIER 2

SECTION A4.601—GENERAL

A4.601.1 Scope. The measures contained in this appendix are not mandatory unless adopted by a city, county, or city and county as specified in Section 101.7. The provisions of this section outline means of achieving enhanced construction or reach levels by incorporating additional green building measures. In order to meet one of the tier levels designers, builders or property owners are required to incorporate additional green building measures necessary to meet the threshold of each level.

A4.601.2 Prerequisite measures. Tier 1 and Tier 2 thresholds require compliance with the mandatory provisions of this code and incorporation of the required prerequisite measures listed in Section A4.601.4.2 for Tier 1 and A4.601.5.2 for Tier 2. Prerequisite measures are also identified in the Residential Occupancies Application Checklist in Section A4.602.
CBC § 509.1 Medium relevance — show source text
SECTION A4.509 —INNOVATIVE CONCEPTS AND LOCAL ENVIRONMENTAL CONDITIONS

A4.509.1 Innovative concepts and local environmental conditions. The provisions of this code are not intended to prevent the use of any alternate material, appliance, installation, device, arrangement, method, design or method of construction not specifically prescribed by this code. This code does not limit the authority of city, county, or city and county government to make necessary changes to the provisions contained in this code pursuant to Section 101.7.1.

APPENDIX A4-20 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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A4 RESIDENTIAL VOLUNTARY MEASURES

DIVISION A4.6 – TIER I AND TIER 2

SECTION A4.601—GENERAL

A4.601.1 Scope. The measures contained in this appendix are not mandatory unless adopted by a city, county, or city and county as specified in Section 101.7. The provisions of this section outline means of achieving enhanced construction or reach levels by incorporating additional green building measures. In order to meet one of the tier levels designers, builders or property owners are required to incorporate additional green building measures necessary to meet the threshold of each level.

A4.601.2 Prerequisite measures. Tier 1 and Tier 2 thresholds require compliance with the mandatory provisions of this code and incorporation of the required prerequisite measures listed in Section A4.601.4.2 for Tier 1 and A4.601.5.2 for Tier 2. Prerequisite measures are also identified in the Residential Occupancies Application Checklist in Section A4.602.

As specified in Section 101.7, additional prerequisite measures may be included by the enforcing agency to address specific local environmental conditions and may be listed in the Innovative Concepts and Local Environmental Conditions portions of the checklist.

A4.601.3 Elective measures. In addition to the required measures, Tier 1 and Tier 2 buildings must incorporate at least the number of elective measures specified in Sections A4.601.4.2 and A4.601.5.2.

A4.601.4 Tier 1. To achieve Tier 1 status a project must comply with the following:

A4.601.4.1 Mandatory measures for Tier 1. The project shall meet or exceed all of the mandatory measures in Chapter 4, Divisions 4.1 through 4.5 and Chapter 7 as applicable.

A4.601.4.2 Prerequisite and elective measures for Tier 1. In addition to the mandatory measures, compliance with the following prerequisite and elective measures from Appendix A4 is also required to achieve Tier 1 status:
1. From Division A4.1, Planning and Design. 1.1. Comply with the topsoil protection requirements in Section A4.106.2.3. 1.2. Comply with the 20 percent permeable paving requirements in Section A4.106.4. 1.3. Comply with the cool roof requirements in Section A4.106.5. 1.4. Comply with the Tier 1 electric vehicle (EV) charging requirements in Section A4.106.8. 1.5. Comply with at least two elective measures selected from Division A4.1.
2. From Division A4.2, Energy Efficiency. 2.1.
CBC § 110.4 Medium relevance — show source text
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 Title 24, Part 6, 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 5. 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 A4.204.1.2: Portable electric spas compliant with 20 CCR, Section 1605.3(g)(7) of the Appliance Efficiency Regulations.

Exception 2 to A4.204.1.2: A pool or spa that is heated solely by a solar pool heating system without any supplementary heater.

Exception 3 to A4.204.1.2: An existing building with inadequate Solar Access Roof Area (SARA) as specified in Title 24, Part 6, Section 170.2(f) for a solar pool heating system to be installed.

Exception 4 to A4.204.1.2: Heating systems which are used exclusively for permanent spa applications in existing buildings with gas availability.

Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code. Reference: Sections 25402, 25402.1, 25402.4 and 25402.8, Public Resources Code.

2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-11

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APPENDIX A4-12 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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A4 RESIDENTIAL VOLUNTARY MEASURES

DIVISION A4.3 – WATER EFFICIENCY AND CONSERVATION

SECTION A4.301—GENERAL (RESERVED)

SECTION A4.302—DEFINITIONS (RESERVED)

SECTION A4.303—INDOOR WATER USE

A4.303.1 Kitchen faucets. The maximum flow rate of kitchen faucets shall not exceed 1.5 gallons per minute at 60 psi. Kitchen faucets may temporarily increase the flow above the maximum rate, but not to exceed 2.2 gallons per minute at 60 psi, and must default to a maximum flow rate of 1.5 gallons per minute at 60 psi.

Note: Where complying faucets are unavailable, aerators or other means may be used to achieve reduction.

A4.303.2 Alternate water sources for nonpotable applications. Alternate nonpotable water sources are used for indoor potable water reduction. Alternate nonpotable water sources shall be installed in accordance with the California Plumbing Code.

A4.303.3 Appliances. Install at least one qualified ENERGY STAR dishwasher or clothes washer.

Note: See Section A5.303.3 for nonresidential dishwashers and clothes washers.

Frequently asked questions

Are Appendix A4 energy measures mandatory statewide?

No. Appendix A4 measures (including Division A4.2 energy provisions) are voluntary at the state level; they only become mandatory in a jurisdiction when that jurisdiction adopts them locally and completes the required Energy Commission/CBSC filings per § A4.201.1 .

What does a builder have to do to use the Division A4.2 performance path?

Compute the building Hourly Source Energy Rating (EDR) with Energy Commission–compliant software, meet the reduced EDR target identified in Table A4.203.1.1, and satisfy at least two prerequisite measures from § A4.203.1.2. Also follow any local Tier checklist if seeking Tier designation (§ A4.203.1; § A4.203.1.2; § A4.203.1.1) .

If a locality wants to accept a lower EDR by relying on larger PV systems, is there any required coordination?

Yes. § A4.203.1.3 requires local jurisdictions to consult the local electric service provider before adopting reduced EDR targets that depend on PV systems larger than the Title 24 Part 6 baseline .

Where do I find the numeric EDR reduction margins?

The numeric margins are published in Table A4.203.1.1, referenced from § A4.203.1.1; review that table in Division A4.2 to get the exact percentage/margin values (§ A4.203.1.1; Table A4.203.1.1) .

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DIVISION A4.6 – TIER 1 AND TIER 2

A4 RESIDENTIAL VOLUNTARY MEASURES

DIVISION A4.7 – RESIDENTIAL MODEL ORDINANCE

A4 RESIDENTIAL VOLUNTARY MEASURES

A4 RESIDENTIAL VOLUNTARY MEASURES

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