Title 24 · California Energy Code
Steep vs low‑slope roof SARA rules, northerly azimuth exclusions and shading considerations
If you’re sizing PV under California Title 24, for steep‑slope roofs you must exclude northerly roof faces between **300° and 90°** from SARA and consider only permanent external shading when computing annual solar access; low‑slope roofs treat all obstructions as shading. If SARA (after exclusions) has less than **80 contiguous ft²**, or the computed minimum PV size is below the code’s minimums (1.8 kW single‑family, 4 kW multifamily), no PV is required. Always compute both the Equation result and the **SARA × 18 (steep)** or **× 14 (low)** target and take the smaller — and consult the cited code exceptions when roof design, snow loads, or pre‑2020 planning conditions apply.
Last reviewed: July 6, 2026
What the code requires — plain English
- For single‑family roofs, Exception 1 to Section 150.1(c)14 (bolded here as § 150.1(c)14) says that for steep‑slope roofs you must exclude roof areas with a northerly azimuth between 300° and 90° (true north) when computing the building’s SARA (Solar Access Roof Area).
- For multifamily up to three stories, the same northerly‑azimuth exclusion appears in Exception 1 to Section 170.2(f) (bolded as § 170.2(f)). The SARA‑based PV requirement compares either the Equation result or SARA × 18 (steep) / SARA × 14 (low‑slope) — whichever produces the smaller required PV output.
The single most important rule: for steep‑slope roofs you do not count northerly roof faces (azimuths from 300° to 90°) toward SARA; for steep‑slope shading calculations consider only external, permanent obstructions (not roof features).
Requirements in detail
Key defined terms (first mention bolded)
- SARA — Solar Access Roof Area: the roof area available and structurally capable of supporting PV that meets the SARA inclusion/exclusion rules.
- Steep‑slope roof — (as used in the PV/SARA rules) roof areas counted using the steep‑slope rules; steep vs low slope triggers different shading and inclusion rules. § 150.1(c)14 and § 170.2(f) distinguish steep‑slope vs low‑slope treatment.
What to include vs exclude when you compute SARA
- Include: roof areas structurally capable of supporting PV (including carport/covered parking roofs and newly constructed structures that can support PV as referenced by Title 24, Part 2, § 1511.10).
- Exclude: any roof area with less than 70% annual solar access. How shading is treated differs by roof slope:
- Steep‑slope roofs: only shading from existing permanent external natural or manmade obstructions (trees, hills, adjacent structures) is considered when determining annual solar access. Do not treat roof‑mounted obstructions or building elevation features as shading for steep slopes unless those obstructions are external permanent objects.
- Low‑slope roofs: shading from all obstructions is considered — this includes external obstructions and obstructions that are part of the building design/elevation (vents, parapets, chimneys, roof equipment).
Northerly‑azimuth exclusion (steep‑slope only)
- Exclude any steep‑slope roof area whose azimuth lies between 300° and 90° (true north) from SARA. This is Exception 1 for both single‑family and multifamily SARA rules.
When a PV system is not required (thresholds)
- Contiguous SARA < 80 ft² → no PV required (both single‑family and multifamily exceptions).
- Minimum PV size exceptions: for single‑family, no PV required when the minimum PV size from the code formula is less than 1.8 kW dc; for multifamily (3 stories or fewer), the exception is less than 4 kW dc.
How the required PV is determined (summary)
- The code requires the installed PV to produce at least the smaller of:
- The PV size from the applicable equation (Equation 150.1‑C for single‑family, Equation 170.2‑C/D for multifamily); or
- The SARA‑based target: SARA × 18 (for steep‑slope SARA) or SARA × 14 (for low‑slope SARA).
Decision‑relevant table
| Decision dimension | Threshold / value (bold) | Effect | Code Reference |
|---|---|---|---|
| Northerly azimuth exclusion (steep) | 300° → 90° | Don’t count these steep‑slope roof faces toward SARA | § 150.1(c)14 ; § 170.2(f) |
| Annual solar access cutoff | 70% | Roof areas below 70% annual solar access are excluded from SARA | § 150.1(c)14 |
| Slope shading rule | Steep: only external permanent obstructions considered; Low: all obstructions considered | Determines which shading to model when computing annual solar access | § 150.1(c)14 ; § 170.2(f) |
| SARA‑based PV target (steep) | SARA × 18 | SARA method target (compare to Equation result and take smaller) | § 150.1(c)14 and related text |
| SARA‑based PV target (low) | SARA × 14 | SARA method target for low‑slope roofs | § 150.1(c)14 and related text |
| Contiguous SARA exemption | 80 contiguous ft² | If SARA < 80 ft², no PV system required | § 150.1(c)14 ; § 170.2(f) |
| Minimum PV system exemption (single‑family) | < 1.8 kW dc | No PV required | § 150.1(c)14 |
| Minimum PV system exemption (multifamily ≤3 stories) | < 4 kW dc | No PV required | § 170.2(f) |
Exceptions & special cases
- Snow‑load / structural infeasibility: If the enforcement authority approves a roof design that makes meeting ASCE 7‑16 Chapter 7 (snow loads) impossible for PV attachment, the PV requirement may be waived (both single‑family and multifamily exceptions reference ASCE).
- Pre‑2020 planning conditions: For buildings approved by the local planning department prior to January 1, 2020 with mandatory conditions of approval, required shading from those steep‑slope roof designs/configurations must be considered in the annual solar access calculations; roof areas prohibited by those conditions are excluded from SARA.
- Solar zone design for steep roofs (related): Other Title 24 solar‑readiness provisions require steep‑slope solar zones to be oriented between 90° and 300° of true north and place constraints on roof obstructions for solar zones; see § 110.10(b). These related rules are for solar‑ready design and overlap conceptually with SARA exclusions.
Common mistakes
- Treating roof‑mounted vents, chimneys or parapets as external shading on steep‑slope roofs — they are not considered for steep slopes when calculating annual solar access (only permanent external obstructions count). This is a frequent error.
- Misreading the azimuth range: the exclusion is 300° to 90° (wraps through north) — that means all directions centered on true north; do not treat it as 300°→90° clockwise only. Confirm orientation with true‑north azimuth.
- Forgetting the 80 contiguous ft² rule — even if a roof has many small pockets of SARA, if no contiguous area meets 80 ft² the PV requirement can be waived.
- Applying low‑slope shading rules to a steep slope (or vice versa); slope classification matters for which obstructions you model.
Worked example — single‑family steep‑slope roof (numbers only from the code text)
Scenario:
- Single‑family home with total structurally eligible steep‑slope roof area = 600 ft².
- Roof faces with azimuths between 300° and 90° (northerly): 150 ft². Per Exception 1 to § 150.1(c)14 exclude these from SARA.
- Remaining steep‑slope area = 600 − 150 = 450 ft². Assume these remaining areas each have ≥70% annual solar access (so they are eligible).
Apply the code rules:
- Contiguous SARA = 450 ft² (well above the 80 ft² exemption), so the PV requirement applies.
- SARA‑based target (steep) = SARA × 18 = 450 × 18 = 8,100 (the SARA‑method result specified in the code text). Compare this SARA target to the PV capacity computed from Equation 150.1‑C for the home; the required PV is the smaller of the two results per § 150.1(c)14. (Because Equation 150.1‑C needs conditioned floor area and the A/B factors from code tables, you must compute both and then take the smaller.)
Note: the code text gives the two alternative sizing approaches and the explicit SARA multiplier values; actual contract kWdc or equipment sizing requires completing Equation 150.1‑C using the project's CFA and the table factors in the code.
Related provisions (quick list)
- § 150.1(c)14 — Single‑family PV & SARA rules (Exception 1 northerly exclusion; 70% solar access; 80 ft² contiguous exemption; min 1.8 kW exception).
- § 170.2(f) — Multifamily (≤3 stories) PV & SARA rules (Exception 1 northerly exclusion; 70% solar access; 80 ft² contiguous exemption; min 4 kW exception).
- § 110.10(b) — Solar zone / solar‑ready solar zone azimuth and obstruction placement rules.
- Title 24, Part 2, § 1511.10 — Structural compatibility / roof areas capable of supporting PV (used when identifying SARA).
- CBC Section 503.1.4 — Occupied roof areas (excluded from SARA under the code).
- ASCE 7‑16, Chapter 7 — Snow load criteria referenced in exceptions for structural infeasibility of PV attachments.
Code references
Grounded in the retrieved California Energy Code — click a citation to read the verbatim passage:
§ 170.2 High relevance — show source text
EQUATION 170.2-C—ANNUAL PHOTOVOLTAIC ELECTRICAL OUTPUT
kW PV = (CFA × A)/1000 + N DU × B)
where:
kW PV = kW dc size of the PV system.
CFA = Conditioned floor area.
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N DU = Number of dwelling units.
A = CFA adjustment factor from Table 170.2-T.
B = Dwelling unit adjustment factor from Table 170.2-T.
Exception 1 to Section 170.2(f): For steep slope roofs, SARA shall not consider roof areas with a northerly azimuth that lies between 300 degrees and 90 degrees from true north. No PV system is required if the SARA is less than 80 contiguous square feet.
Exception 2 to Section 170.2(f): No PV system is required when the minimum PV system size specified by Section 170.2(f) is less than 4 kW dc .
Exception 3 to Section 170.2(f): Buildings with enforcement-authority-approved roof designs, where the enforcement authority determines it is not possible for the PV system, including panels, modules and components and supports and attachments to the roof structure, to meet the requirements of American Society of Civil Engineers (ASCE) Standard 7-16, Chapter 7, Snow Loads.
Exception 4 to Section 170.2(f): For buildings that are approved by the local planning department prior to January 1, 2020 with mandatory conditions of approval: a. Shading from roof designs and configurations for steep slope roofs shall be considered for the annual solar access calculations; and
b. Roof areas that are not allowed to have PVs by the mandatory conditions of approval shall not be considered in determining the SARA.
Exception 5 to Section 170.2(f): PV system sizes determined using Equation 170.2-C may be reduced by 25 percent if installed in conjunction with a BESS. The BESS shall meet the qualification requirements specified in Joint Appendix JA12 and have a minimum cycling capacity of 7.5 kWh as defined in Joint Appendix JA12.
TABLE 170.2-T—CFA AND DWELLING UNIT ADJUSTMENT FACTORS Col2 Col3 CLIMATE ZONE A—CFA B—DWELLING UNITS 1 0.793 1.27 2 0.621 1.22 3 0.628 1.12 4 0.586 1.21 5 0.585 1.06 6 0.594 1.23 7 0.572 1.15 8 0.586 1.37 9 0.613 1.36 10 0.627 1.41 11 0.836 1.44 12 0.613 1.40 13 0.894 1.51 14 0.741 1.26 15 1.56 1.47 16 0.59 1.22 (g) **Photovoltaic requirements—more than three habitable stories.
§ 1511.10. High relevance — show source text
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A. SARA includes the area of the building’s roof space capable of structurally supporting a PV system, and the area of all roof space on covered parking areas, carports and all other newly constructed structures on the site that are compatible with supporting a PV system per Title 24, Part 2, Section 1511.10.
B. SARA does NOT include:
i. Any roof area that has less than 70 percent annual solar access. Annual solar access is determined by dividing the total annual solar insolation, accounting for shading obstructions, by the total annual solar insolation if the same areas were unshaded by obstructions. For steep slope roofs, only shading from existing permanent natural or manmade obstructions that are external to the dwelling, including but not limited to trees, hills, and adjacent structures, shall be considered for annual solar access calculations. For low slope roofs, all obstructions, including those that are external to the dwelling unit, and obstructions that are part of the building design and elevation features shall be considered for the annual solar access calculations. ii. Occupied roof areas as specified by CBC Section 503.1.4. iii. Roof area that is otherwise not available due to compliance with: a. Other state building code requirements, or b. Local building code requirements if local building code requirements are confirmed by the Executive Director .
EQUATION 150.1-C—ANNUAL PHOTOVOLTAIC ELECTRICAL OUTPUT kW PV = (CFA × A)/1000 +(N DU × B)
where:
kW PV = kW dc size of the PV system.
CFA = Conditioned floor area.
N DU = Number of dwelling units. A = CFA adjustment factor from Table 150.1-C. B = Dwelling unit adjustment factor from Table 150.1-C. Exception 1 to Section 150.1(c)14: For steep slope roofs, SARA shall not consider roof areas with a northerly azimuth that lies between 300 degrees and 90 degrees from true north. No PV system is required if the SARA is less than 80 contiguous square feet. Exception 2 to Section 150.1(c)14: No PV system is required when the minimum PV system size specified by Section 150.1(c)14 is less than 1.8 kW dc . Exception 3 to Section 150.1(c)14: Buildings with enforcement-authority-approved roof designs, where the enforcement authority determines it is not possible for the PV system, including panels, modules and components and supports and attachments to the roof structure, to meet the requirements of the American Society of Civil Engineers (ASCE), Standard 7-16, Chapter 7, Snow Loads. Exception 4 to Section 150.1(c)14: For buildings that are approved by the local planning department prior to January 1, 2020 with mandatory conditions for approval: a. Shading from roof designs and configurations for steep-sloped roofs, which are required by the mandatory conditions for approval, shall be considered for the annual solar access calculations; and b. Roof areas that are not allowed by the mandatory conditions for approval to have PVs shall not be considered in determining the SARA.
§ 150.1 High relevance — show source text
where:
kW PV = kW dc size of the PV system.
CFA = Conditioned floor area.
N DU = Number of dwelling units. A = CFA adjustment factor from Table 150.1-C. B = Dwelling unit adjustment factor from Table 150.1-C. Exception 1 to Section 150.1(c)14: For steep slope roofs, SARA shall not consider roof areas with a northerly azimuth that lies between 300 degrees and 90 degrees from true north. No PV system is required if the SARA is less than 80 contiguous square feet. Exception 2 to Section 150.1(c)14: No PV system is required when the minimum PV system size specified by Section 150.1(c)14 is less than 1.8 kW dc . Exception 3 to Section 150.1(c)14: Buildings with enforcement-authority-approved roof designs, where the enforcement authority determines it is not possible for the PV system, including panels, modules and components and supports and attachments to the roof structure, to meet the requirements of the American Society of Civil Engineers (ASCE), Standard 7-16, Chapter 7, Snow Loads. Exception 4 to Section 150.1(c)14: For buildings that are approved by the local planning department prior to January 1, 2020 with mandatory conditions for approval: a. Shading from roof designs and configurations for steep-sloped roofs, which are required by the mandatory conditions for approval, shall be considered for the annual solar access calculations; and b. Roof areas that are not allowed by the mandatory conditions for approval to have PVs shall not be considered in determining the SARA. Exception 5 to Section 150.1(c)14: PV system sizes determined using Equation 150.1-C may be reduced by 25 percent if installed in conjunction with a BESS. The BESS shall meet the qualification requirements specified in Joint Appendix JA12 and have a minimum cycling capacity of 7.5 kWh as defined in Joint Appendix JA12. 15. Ventilation system fault indicator display (FID): All HRV/ERV systems serving individual dwelling units shall have a fault indicator display (FID) that is ECC-Rater field verified as specified in Joint Appendix JA17.
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|TABLE 150.
§ 170.2 High relevance — show source text
ii. Reserved.
iii. Neon or cold cathode lamps with transformer or power supply efficiency greater than or equal to the following: a. A minimum efficiency of 75 percent when the transformer or power supply rated output current is less than 50 mA; or
b. A minimum efficiency of 68 percent when the transformer or power supply rated output current is 50 mA or greater. The ratio of the output wattage to the input wattage is at 100 percent tubing load.
iv. Reserved.
v. Light emitting diodes (LEDs) with a power supply having an efficiency of 80 percent or greater; or Exception to Section 170.2(e)7Bv: Single voltage external power supplies that are designed to convert 120 volt AC input into lower voltage DC or AC output, and have a nameplate output power less than or equal to 250 watts, shall comply with the applicable requirements of the Appliance Efficiency Regulations (Title 20). Exception 1 to Section 170.2(e)7: Unfiltered incandescent lamps that are not part of an electronic message center (EMC), an internally illuminated sign or an externally illuminated sign. Exception 2 to Section 170.2(e)7: Exit signs. Exit signs shall meet the requirements of the Appliance Efficiency Regulations. Exception 3 to Section 170.2(e)7: Traffic signs that meet the requirements of the Appliance Efficiency Regulations, Sections 1601(m), 1602, 1602.1, 1603, 1604(m), 1605, 1605.1(m), 1605.2(m), 1605.3(m), 1606, 1607, 1608, and 1609.
(f) Photovoltaic requirements—three habitable stories or fewer . All multifamily buildings up to three habitable stories shall have a newly installed photovoltaic (PV) system or newly installed PV modules meeting the minimum qualification requirements specified in Joint Appendix JA11. The annual electrical output of the PV system shall be no less than the smaller of a PV system size determined using Equation 170.2-C, or the total solar access roof area (SARA) multiplied by 18 for steep-sloped roofs or SARA multiplied by 14 for low-sloped roofs. A. SARA includes the area of the building’s roof space capable of structurally supporting a PV system, and the area of all roof space on covered parking areas, carports, and all other newly constructed structures on the site that are compatible with supporting a PV system per Title 24, Part 2, Section 1511.10.
B. SARA does NOT include:
i. Any roof area that has less than 70 percent annual solar access. Annual solar access is determined by dividing the total annual solar insolation, accounting for shading obstructions, by the total annual solar insolation if the same areas were unshaded by obstructions. For steep-sloped roofs, only shading from existing permanent natural or manmade obstructions that are external to the dwelling, including but not limited to trees, hills and adjacent structures, shall be considered for annual solar access calculations. For low slope roofs, all obstructions including those that are external to the dwelling unit, and obstructions that are part of the building design and elevation features, shall be considered for the annual solar access calculations.
ii. Occupied roof areas as specified by CBC Section 503.1.4. iii. Roof area that is otherwise not available due to compliance with: a. Other state building code requirements, or b. Local building code requirements if local building code requirements are confirmed by the Executive Director.
§ 170.2 High relevance — show source text
All multifamily buildings up to three habitable stories shall have a newly installed photovoltaic (PV) system or newly installed PV modules meeting the minimum qualification requirements specified in Joint Appendix JA11. The annual electrical output of the PV system shall be no less than the smaller of a PV system size determined using Equation 170.2-C, or the total solar access roof area (SARA) multiplied by 18 for steep-sloped roofs or SARA multiplied by 14 for low-sloped roofs. A. SARA includes the area of the building’s roof space capable of structurally supporting a PV system, and the area of all roof space on covered parking areas, carports, and all other newly constructed structures on the site that are compatible with supporting a PV system per Title 24, Part 2, Section 1511.10.
B. SARA does NOT include:
i. Any roof area that has less than 70 percent annual solar access. Annual solar access is determined by dividing the total annual solar insolation, accounting for shading obstructions, by the total annual solar insolation if the same areas were unshaded by obstructions. For steep-sloped roofs, only shading from existing permanent natural or manmade obstructions that are external to the dwelling, including but not limited to trees, hills and adjacent structures, shall be considered for annual solar access calculations. For low slope roofs, all obstructions including those that are external to the dwelling unit, and obstructions that are part of the building design and elevation features, shall be considered for the annual solar access calculations.
ii. Occupied roof areas as specified by CBC Section 503.1.4. iii. Roof area that is otherwise not available due to compliance with: a. Other state building code requirements, or b. Local building code requirements if local building code requirements are confirmed by the Executive Director.
EQUATION 170.2-C—ANNUAL PHOTOVOLTAIC ELECTRICAL OUTPUT
kW PV = (CFA × A)/1000 + N DU × B)
where:
kW PV = kW dc size of the PV system.
CFA = Conditioned floor area.
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N DU = Number of dwelling units.
A = CFA adjustment factor from Table 170.2-T.
B = Dwelling unit adjustment factor from Table 170.2-T.
Exception 1 to Section 170.2(f): For steep slope roofs, SARA shall not consider roof areas with a northerly azimuth that lies between 300 degrees and 90 degrees from true north. No PV system is required if the SARA is less than 80 contiguous square feet.
Exception 2 to Section 170.2(f): No PV system is required when the minimum PV system size specified by Section 170.2(f) is less than 4 kW dc .
Exception 3 to Section 170.2(f): Buildings with enforcement-authority-approved roof designs, where the enforcement authority determines it is not possible for the PV system, including panels, modules and components and supports and attachments to the roof structure, to meet the requirements of American Society of Civil Engineers (ASCE) Standard 7-16, Chapter 7, Snow Loads.
§ 170.2 High relevance — show source text
b. Roof areas that are not allowed to have PVs by the mandatory conditions of approval shall not be considered in determining the SARA.
Exception 5 to Section 170.2(f): PV system sizes determined using Equation 170.2-C may be reduced by 25 percent if installed in conjunction with a BESS. The BESS shall meet the qualification requirements specified in Joint Appendix JA12 and have a minimum cycling capacity of 7.5 kWh as defined in Joint Appendix JA12.
TABLE 170.2-T—CFA AND DWELLING UNIT ADJUSTMENT FACTORS Col2 Col3 CLIMATE ZONE A—CFA B—DWELLING UNITS 1 0.793 1.27 2 0.621 1.22 3 0.628 1.12 4 0.586 1.21 5 0.585 1.06 6 0.594 1.23 7 0.572 1.15 8 0.586 1.37 9 0.613 1.36 10 0.627 1.41 11 0.836 1.44 12 0.613 1.40 13 0.894 1.51 14 0.741 1.26 15 1.56 1.47 16 0.59 1.22 (g) Photovoltaic requirements—more than three habitable stories. All newly constructed building types specified in Table 170.2-U, or mixed occupancy buildings where at least 80 percent of the floor area of the building serves one or more of these building types, shall have a newly installed photovoltaic (PV) system meeting the minimum qualification requirements of Reference Joint Appendix JA11. The PV capacity in kW dc shall not be less than the smaller of the minimum rated PV system capacity determined by Equation 170.2-D, or the total of all available solar access roof areas (SARA) multiplied by 18 for steep-sloped roofs or multiplied by 14 for low-sloped roofs. In mixed occupancy buildings, the minimum rated PV system capacity for the building shall be determined by applying Equation 170.2-D to the conditioned floor area of each of the listed building types and summing the capacities determined for each.
SARA include the area of the building’s roof space capable of structurally supporting a PV system, and the area of all roof space on covered parking areas, carports and all other newly constructed structures on the site that are compatible with supporting a PV system per Title 24, Part 2, Section 1511.10.
SARA does not include:
A. Any area that has less than 70 percent annual solar access. Annual solar access is determined by dividing the total annual solar insolation (accounting for shading obstructions) by the total annual solar insolation if the same areas were unshaded by those obstructions. For all roofs, all obstructions including those that are external to the building,
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and obstructions that are part of the building design and elevation features, may be considered for the annual solar access calculations.
§ 170.2 High relevance — show source text
The PV capacity in kW dc shall not be less than the smaller of the minimum rated PV system capacity determined by Equation 170.2-D, or the total of all available solar access roof areas (SARA) multiplied by 18 for steep-sloped roofs or multiplied by 14 for low-sloped roofs. In mixed occupancy buildings, the minimum rated PV system capacity for the building shall be determined by applying Equation 170.2-D to the conditioned floor area of each of the listed building types and summing the capacities determined for each.
SARA include the area of the building’s roof space capable of structurally supporting a PV system, and the area of all roof space on covered parking areas, carports and all other newly constructed structures on the site that are compatible with supporting a PV system per Title 24, Part 2, Section 1511.10.
SARA does not include:
A. Any area that has less than 70 percent annual solar access. Annual solar access is determined by dividing the total annual solar insolation (accounting for shading obstructions) by the total annual solar insolation if the same areas were unshaded by those obstructions. For all roofs, all obstructions including those that are external to the building,
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and obstructions that are part of the building design and elevation features, may be considered for the annual solar access calculations.
B. Occupied roofs as specified by CBC Section 503.1.4. C. Roof area that is otherwise not available due to compliance with: i. Other state building code requirements, or ii. Local building code requirements if the local building code requirements are confirmed by the Executive Director.
EQUATION 170.2-D—PHOTOVOLTAIC DIRECT CURRENT CAPACITY
kW PVdc = (CFA × A)/1000
where:
kW PVdc = Minimum rated PV system capacity in kW.
CFA = Conditioned floor area in square feet.
A = PV capacity factor in W/square foot as specified in Table 170.2-U for the building type.
Exception 1 to Section 170.2(g): No PV system is required where the total of all available SARA is less than 3 percent of the conditioned floor area.
Exception 2 to Section 170.2(g): No PV system is required where the required PV system capacity is less than 4 kW dc .
Exception 3 to Section 170.2(g): No PV system is required if the SARA contains less than 80 contiguous square feet.
Exception 4 to Section 170.2(g): Buildings with enforcement-authority-approved roof designs, where the enforcement authority determines it is not possible for the PV system, including panels, modules, components, supports and attachments to the roof structure, to meet ASCE 7-16, Chapter 7, Snow Loads.
§ 150.1 High relevance — show source text
Exception 1 to Section 150.1(c)11: Building integrated photovoltaic panels and building integrated solar thermal panels are not required to comply with the minimum requirements for aged solar reflectance and thermal emittance or SRI. Exception 2 to Section 150.1(c)11: Roof constructions with a weight of at least 25 lb/ft [2] are not required to comply with the minimum requirements for aged solar reflectance and thermal emittance or SRI. 12. Ventilation cooling. Single-family homes shall comply with the whole-house fan (WHF) requirements shown in Table 150.1A. When a WHF is required, comply with Subsections A, B and C below. A. Have installed one or more WHFs whose total airflow cfm is equal to or greater than 1.5 cfm/ft [2] of conditioned floor area. Airflow cfm for WHFs shall be determined based on the airflow listed in the Home Ventilating Institute Certified Products Directory. B. Have at least 1 square foot of attic vent free area for each 750 cfm of rated whole-house fan airflow cfm, or if the manufacturer has specified a greater free vent area, the manufacturer’s free vent area specifications. Exception to Section 150.1(c)12B: WHFs that are directly vented to the outside. C. Provide homeowners who have WHFs with a one page “How to operate your whole-house fan” informational sheet. Exception to Section 150.1(c)12: New dwelling units with a conditioned floor area of 500 square feet or less shall not be required to comply with the WHF requirements. 13. HVAC system bypass ducts. Bypass ducts that deliver conditioned supply air directly to the space-conditioning system return duct airflow shall not be used.
- Photovoltaic requirements. All single-family residential buildings shall have a newly installed photovoltaic (PV) system or newly installed PV modules meeting the minimum qualification requirements specified in Joint Appendix JA11. The annual electrical output of the PV system shall be no less than the smaller of a PV system size determined using Equation 150.1-C, or the total solar access roof area (SARA) multiplied by 18 for steep-sloped roofs or multiplied by 14 for low-sloped roofs.
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A. SARA includes the area of the building’s roof space capable of structurally supporting a PV system, and the area of all roof space on covered parking areas, carports and all other newly constructed structures on the site that are compatible with supporting a PV system per Title 24, Part 2, Section 1511.10.
B. SARA does NOT include:
i. Any roof area that has less than 70 percent annual solar access. Annual solar access is determined by dividing the total annual solar insolation, accounting for shading obstructions, by the total annual solar insolation if the same areas were unshaded by obstructions. For steep slope roofs, only shading from existing permanent natural or manmade obstructions that are external to the dwelling, including but not limited to trees, hills, and adjacent structures, shall be considered for annual solar access calculations. For low slope roofs, all obstructions, including those that are external to the dwelling unit, and obstructions that are part of the building design and elevation features shall be considered for the annual solar access calculations.
§ 9.3 High relevance — show source text
9.3**|SDR 11|SDR 11|SDR 10|SDR 11|SDR 11|SDR 11|SDR 11| |ACTUAL ID:|0.660|0.860|1.077|1.328|1.554|1.943|2.864|3.682| |LENGTH (feet)
|CAPACITY IN THOUSANDS OF BTU PER HOUR
|CAPACITY IN THOUSANDS OF BTU PER HOUR
|CAPACITY IN THOUSANDS OF BTU PER HOUR
|CAPACITY IN THOUSANDS OF BTU PER HOUR
|CAPACITY IN THOUSANDS OF BTU PER HOUR
|CAPACITY IN THOUSANDS OF BTU PER HOUR
|CAPACITY IN THOUSANDS OF BTU PER HOUR
|CAPACITY IN THOUSANDS OF BTU PER HOUR
| |10
|340
|680
|1230
|2130
|3210
|5770
|16 000
|30 900
| |20
|233
|468
|844
|1460
|2210
|3970
|11 000
|21 200
| |30
|187
|375
|677
|1170
|1770
|3180
|8810
|17 000
| |40
|160
|321
|580
|1000
|1520
|2730
|7540
|14 600
| |50
|142
|285
|514
|890
|1340
|2420
|6680
|12 900
| |60
|129
|258
|466
|807
|1220
|2190
|6050
|11 700
| |70
|119
|237
|428
|742
|1120
|2010
|5570
|10 800
| |80
|110
|221
|398
|690
|1040
|1870
|5180
|10 000
| |90
|103
|207
|374
|648
|978
|1760
|4860
|9400
| |100
|98
|196
|353
|612
|924
|1660
|4590
|8900<§ 1507.5 Medium relevance — show source text
5|1507.5| |Mineral-
surfaced
roll roofing|1507.6|1507.6|1507.6| |Slate
shingles|1507.7|1507.7|1507.7| |Wood
shingles|1507.8|1507.8|1507.8| |Wood
shakes|1507.9|1507.9|1507.9| |BIPV roof
coverings|1507.16|Underlayment shall be one of the following:
1.
For roof slopes from 3 units vertical in 12 units
horizontal (3:12) to 4 units vertical in 12 units
horizontal (4:12), underlayment shall be two layers
applied in the following manner: Apply a strip of
underlayment that is half the width of a full sheet
parallel to and starting at the eaves. Starting at the
eaves, apply full-width sheets of underlayment,
overlapping successive sheets half the width of a full
sheet plus 2 inches. End laps shall be 4 inches and
shall be offset by 6 feet. Distortions in the
underlayment shall not interfere with the ability of
the shingles to seal.
2.
For roof slopes of 4 units vertical in 12 units
horizontal (4:12) or greater, underlayment shall be
one layer applied as follows: Underlayment shall be
applied shingle fashion, parallel to and starting from
the eaves and lapped 2 inches. Distortions in the
underlayment shall not interfere with the ability of
the shingles to seal. End laps shall be 4 inches and
shall be offset by 6 feet.
3.
A single layer of self-adhering polymer modified
bitumen underlayment complying with ASTM
D1970, installed in accordance with the
underlayment and roof covering manufacturers’
installation instructions for the deck material, roof
ventilation configuration, and climate exposure of
the roof covering.|Underlayment shall be one of the following:
1.
Two layers of mechanically fastened underlayment
applied in the following manner: Apply a strip of
underlayment that is half the width of a full sheet
parallel to and starting at the eaves, fastened
sufficiently to hold in place. Starting at the eaves,
apply full-width sheets of underlayment,
overlapping successive sheets half the width of a full
sheet plus 2 inches. Distortions in the underlayment
shall not interfere with the ability of the shingles to
seal. End laps shall be 4 inches and shall be offset by
6 feet.
2.
A strip not less than 4 inches in width of self-
adhering polymer modified bitumen underlayment
complying with ASTM D1970, installed in
accordance with the manufacturer’s installation
instructions for the deck material, shall be applied
over all joints in the roof decking. An approved
underlayment complying with Table 1507.1.1(1) for
the applicable roof covering and basic wind speed
shall be applied over the entire roof over the 4-inch-
wide membrane strips.§ 110.10 Medium relevance — show source text
Exception 3 to Section 110.10(b)1B: Buildings with a designated solar zone area that is no less than 50 percent of the potential solar zone area. The potential solar zone area is the total area of any low-sloped roofs where the annual solar access is 70 percent or greater and any steep-sloped roofs oriented between 90 degrees and 300 degrees of true north where the annual solar access is 70 percent or greater. Solar access is the ratio of solar insolation including shade to the solar insolation without shade. Shading from obstructions located on the roof or any other part of the building shall not be included in the determination of annual solar access.
Exception 4 to Section 110.10(b)1B: Low-rise and high-rise multifamily buildings with all thermostats in each dwelling unit are demand response controls that comply with Section 110.12(a), and are capable of receiving and responding to Demand Response Signals prior to granting of an occupancy permit by the enforcing agency. In addition, either A or B below:
A. In each dwelling unit, comply with one of the following measures: i. Install a dishwasher that meets or exceeds the ENERGY STAR Program requirements with either a refrigerator that meets or exceeds the ENERGY STAR Program requirements or a whole house fan driven by an electronically commutated motor; or ii. Install a home automation system that complies with Section 110.12(a) and is capable of, at a minimum, controlling the appliances and lighting of the dwelling and responding to demand response signals; or iii. Install alternative plumbing piping to permit the discharge from the clothes washer and all showers and bathtubs to be used for an irrigation system in compliance with the California Plumbing Code and any applicable local ordinances; or iv. Install a rainwater catchment system designed to comply with the California Plumbing Code and any applicable local ordinances, and that uses rainwater flowing from at least 65 percent of the available roof
area.
B. Meet the Title 24, Part 11, Section A4.106.8.2 requirements for electric vehicle charging spaces.
Exception 5 to Section 110.10(b)1B: Buildings where the roof is designed and approved to be used for vehicular traffic or parking or for a heliport. 2. Azimuth range. All sections of the solar zone located on steep-sloped roofs shall have an azimuth range between 90 degrees and 300 degrees of true north. 3. Shading. A. No obstructions, including but not limited to, vents, chimneys, architectural features and roof mounted equipment, shall be located in the solar zone.
B. Any obstruction, located on the roof or any other part of the building that projects above a solar zone shall be located at least twice the distance, measured in the horizontal plane, of the height difference between the highest point of the obstruction and the horizontal projection of the nearest point of the solar zone, measured in the vertical plane. Exception to Section 110.10(b)3: Any roof obstruction, located on the roof or any other part of the building, that is oriented north of all points on the solar zone. 4. Structural design loads on construction documents. For areas of the roof designated as solar zone, the structural design loads for roof dead load and roof live load shall be clearly indicated on the construction documents.
Note: Section 110.10(b)4 does not require the inclusion of any collateral loads for future solar energy systems.
§ 170.2 Medium relevance — show source text
The rated energy capacity shall be not less than the Minimum Rated Useable Energy Capacity determined by Equation 170.2-E, or by Equation 170.2-F if SARA was used to determine the PV capacity in Section 170.2-D, and the rated power capacity shall be not less than the Minimum Power Capacity determined by Equation 170.2-G. In mixed occupancy buildings, the total battery system capacity for the building shall be determined by applying the Minimum Rated Usable Energy Capacity to each of the listed building types and summing the capacities determined for each.
EQUATION 170.2-E—BATTERY ENERGY STORAGE SYSTEM MINIMUM RATED USABLE ENERGY CAPACITY kWh batt = k((CFA × B)/(1000 × C [0.5] ))
— EQUATION 170.2-F BATTERY ENERGY STORAGE SYSTEM MINIMUM RATED USABLE ENERGY CAPACITY, SARA-ADJUSTED kWh batt = k((CFA × B)/(1000 × C [0.5] )) × (kWP Vdc,SARA /kWP Vdc )
268 2025 CALIFORNIA ENERGY CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
MULTIFAMILY BUILDINGS—PERFORMANCE AND PRESCRIPTIVE COMPLIANCE APPROACHES
where:
kWh batt = Minimum Rated Usable Energy Capacity of the BESS in kWh.
kW PVdc = Minimum Rated PV System Capacity in kW from Equation 170.2D. kW PVdc, SARA = Minimum Rated PV System Capacity in kW from the SARA calculation. CFA = Conditioned floor area that is subject to the PV system requirements of Section 170.2(g) in square feet.
B = BESS Capacity Factor in Wh/square foot as specified in Table 170.2-V for the building type.
C = Rated single charge-discharge cycle AC to AC (round-trip) efficiency of the BESS.
EQUATION 170.2-G—BATTERY ENERGY STORAGE SYSTEM MINIMUM RATED POWER CAPACITY
kW batt = kW batt /4
where:
kW batt = Minimum Rated Power Capacity of the BESS in kW dc .
kWh batt = Minimum Rated Usable Energy Capacity of the BESS in kWh.
Exception 1 to Section 170.2(h): No BESS is required if the installed PV system capacity is less than 15 percent of the capacity determined by Equation 170.2-D.
Exception 2 to Section 170.2(h): No BESS is required in buildings with BESS requirements with less than 10 kWh minimum rated usable energy capacity.
|TABLE 170.
Frequently asked questions
What exactly is excluded by the northerly azimuth rule?
All steep‑slope roof areas whose azimuth lies between 300° and 90° (true north) are not counted in SARA under Exception 1 to § 150.1(c)14 (single‑family) and Exception 1 to § 170.2(f) (multifamily).
Do I still model roof‑top vents or chimneys as shading on a steep roof?
No — for steep‑slope roofs the annual solar access calculation only considers existing permanent external obstructions (trees, hills, adjacent structures). Roof‑mounted elements that are part of the building are not counted as external shading for steep slopes. For low‑slope roofs, however, all obstructions (including roof elements) are included.
When can I claim the “no PV” exemption because of small area?
If the building’s usable SARA contains less than 80 contiguous square feet, the code’s exceptions allow no PV system to be required. This applies both in § 150.1(c)14 and § 170.2(f).
How do I decide whether to use the SARA×18 (or ×14) target or the equation?
The code requires you to compute both: the PV size from the applicable equation (Equation 150.1‑C or 170.2‑C/D) and the SARA‑based target (SARA × 18 for steep or × 14 for low). The required PV is the smaller of those two results.
Where does ASCE snow‑load come into play?
If an enforcement authority (AHJ) approves a roof design and determines the PV system cannot meet ASCE 7‑16, Chapter 7 snow‑load attachment requirements, that is an exception to the PV requirement (i.e., the PV requirement may be waived).
More in California Energy Code
- Compliance paths, energy budgets, performance modeling and forms/software requirements
- Controls, commissioning, demand-response, sensors, and field verification/diagnostic testing
- Domestic hot water systems, efficiency, controls and installation requirements
- Electrical infrastructure, EV charging readiness, load management and demand controls
- Envelope construction, insulation, fenestration and thermal performance
- HVAC systems, ventilation rates, ducting, controls and testing
- Interior and exterior lighting power, controls and daylighting requirements
- Mandatory measures, appliance efficiency and certification requirements
- Photovoltaic requirements, BESS (battery energy storage) sizing and SARA procedures
- Reference appendices, test procedures, product certification and labeling requirements
- Scope, applicability, definitions and administrative requirements
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