Title 24 · California Energy Code
Which building types and story counts trigger PV and BESS requirements
If you're designing a new building, check: nonresidential/hotel follow **§140.10**, multifamily rules split at **three habitable stories** (≤3 use §170.2(f)/(g); >3 use §170.2(g)/(h)), and single‑family new homes use **§150.1(c)14**. Each section gives a CFA‑based equation or a SARA alternative that determines the minimum PV size; when that PV requirement applies the code often requires a BESS sized by the stated equations — unless small‑system or other listed exceptions (for example **4 kW**, **1.8 kW**, **15%**, **10 kWh**, or **80 ft² SARA**) remove the requirement. Always use the climate‑zone and building‑type values from the tables and follow the referenced Joint Appendices for PV/BESS qualification.
Last reviewed: July 6, 2026
What the code requires — plain English
New buildings in several categories must install photovoltaic (PV) systems; in many of those cases a battery energy storage system (BESS) is also required. The prescriptive PV/BESS triggers and sizing rules for nonresidential and hotel/motel buildings are in § 140.10. Multifamily buildings are split by height: ≤ three habitable stories (PV rules in § 170.2(f) / § 170.2(g) for three or fewer and more than three, respectively) and > three habitable stories (PV and mandatory BESS in § 170.2(g) and § 170.2(h)). Single‑family residential PV requirements appear at § 150.1(c)14. Each cited section contains the controlling equations, capacity‑factor tables, and exceptions that determine whether PV and/or BESS are required.
Most important: if your project is a nonresidential/hotel, a multifamily building more than three habitable stories, or a single‑family new dwelling the code gives a formula and table(s) that determine a minimum PV size — and in most cases a BESS is required when that PV requirement applies.
Requirements in detail
Decision dimensions (short table)
| Building type / condition | What triggers PV? | Does BESS get triggered? | Key thresholds / dimensions | Code Reference |
|---|---|---|---|---|
| Nonresidential & hotel/motel | PV required when Equation 140.10‑A (CFA × A /1000) or SARA method yields required capacity (subject to exceptions). | Yes — if PV is required the building generally must also provide a BESS sized by Equations 140.10‑B/‑C/‑D, with listed exceptions. | PV minimum exception: no PV if required PV < 4 kW dc; SARA rules and 80 contiguous ft² exception; BESS exceptions: no BESS if installed PV < 15% of calculated capacity or if BESS energy < 10 kWh. | § 140.10 |
| Multifamily — ≤ three habitable stories | PV required per Equation 170.2‑C or SARA method (SARA × 18 for steep or × 14 for low roof). | No mandatory BESS in the ≤3‑story prescriptive rule (BESS rules apply for >3 stories). | PV minimum exception: no PV if required PV < 4 kW dc; SARA < 80 contiguous ft² or total SARA < 3% of CFA are exceptions. | § 170.2(f) / § 170.2(g) |
| Multifamily — > three habitable stories | All listed building types in Table 170.2‑U (or mixed occupancy where ≥80% floor area matches) must have PV sized by Equation 170.2‑D or SARA method. | Yes — mandatory BESS sized by Equation 170.2‑E (or 170.2‑F if SARA/SARA‑adjusted) and power by Equation 170.2‑G; exceptions apply. | Same PV exceptions as ≤3 stories; BESS exceptions: no BESS if installed PV < 15% of required PV or BESS energy < 10 kWh. | § 170.2(g) and § 170.2(h) |
| Single‑family residential (new) | PV required per Equation 150.1‑C / sizing in §150.1(c)14 (or SARA); limited exceptions. | BESS is not universally required, but installing a BESS can reduce the PV size by 25% if the BESS meets JA12 and minimum cycling capacity 7.5 kWh. | PV not required if SARA < 80 contiguous ft² or if PV < 1.8 kW dc (single‑family threshold). | § 150.1(c)14 |
(“CFA” = conditioned floor area; “SARA” = solar access roof area; A, B are capacity factors taken from Table 140.10‑A, Table 170.2‑U, or Table 170.2‑V as applicable — see each section.)
How PV size is determined (where it triggers)
- Calculated PV method (typical): the code gives an equation of the form kW PVdc = (CFA × A)/1000 (Equation 140.10‑A for nonresidential; Equation 170.2‑D for multifamily), where A is the PV capacity factor (W/ft²) from the appropriate table.
- Alternate SARA method: the PV requirement may be the smaller of the equation result or total SARA × 18 W/ft² (steep) or × 14 W/ft² (low) (multifamily §§170.2 and ≤3‑story rules; similar language in §140.10 alternatives).
How BESS is triggered and sized
- Trigger: If a building is required to have PV per the section, a BESS is required in many of those cases (explicit for §140.10 buildings and multifamily >3 stories in §170.2(h)).
- Energy sizing: use Equation 140.10‑B / 140.10‑C (nonresidential) or Equation 170.2‑E / 170.2‑F (multifamily) — they compute Minimum Rated Usable Energy Capacity (kWh) from CFA × B (B = BESS capacity factor, Wh/ft²) and the BESS round‑trip efficiency C.
- Power sizing: Equation 140.10‑D / 170.2‑G define minimum power as a fraction (kW batt = kW batt / 4 in the text) — see each equation.
Exceptions & special cases
- SARA limitations: No PV required where total available SARA < 3% of CFA (nonresidential/multifamily) or where SARA < 80 contiguous ft². (See exceptions to §140.10(a), §170.2(g)/(f), and §150.1(c)14.)
- Small‑size exceptions:
- Nonresidential/multifamily: no PV if required PV < 4 kW dc.
- Single‑family: no PV if minimum PV < 1.8 kW dc.
- BESS exceptions (when BESS would otherwise be required):
- No BESS if the installed PV system capacity is less than 15% of the capacity determined by the governing PV equation (both §140.10(b) and §170.2(h)).
- No BESS if the calculated minimum rated usable energy capacity is less than 10 kWh (both §140.10 and §170.2).
- For multitenant nonresidential buildings, BESS sizing is based only on tenant spaces > 5,000 ft²; single‑tenant buildings under 5,000 ft² do not require BESS per §140.10 exception.
- Roof structural / snow load / local constraints: the enforcement authority may allow exceptions where roof design cannot safely support PV (ASCE 7‑16 snow rules), and local planning conditions can affect what SARA counts (see each section exceptions).
- PV reduction with BESS (incentive): In single‑family §150.1(c)14 and multifamily §170.2(f) there is an allowance to reduce required PV size by 25% if you install a qualifying BESS (JA12) with minimum cycling capacity (single‑family: 7.5 kWh; multifamily same JA12 reference).
Common mistakes
- Assuming “multifamily” rules are the same regardless of stories — they are not. >3 habitable stories has separate, stricter rules including mandatory BESS (§170.2(g)/(h)). Do not apply the ≤3‑story logic to higher buildings.
- Forgetting the small‑system exceptions — many PV triggers are waived if the calculated PV is below 4 kW dc (nonresidential/multifamily) or 1.8 kW dc (single‑family). Always check the minimum PV threshold.
- Treating SARA as “all roof area.” SARA excludes roof area below 70% annual solar access, occupied roofs, and areas precluded by local/state code or planning conditions — check the section definitions carefully.
- Omitting BESS exceptions: if the actual installed PV is much smaller (e.g., due to a partial installation or a community solar offset), the BESS requirement may be removed by the 15% or 10 kWh exceptions — document these conditions.
Worked example — 4‑story multifamily building (concrete numbers)
Scenario: New multifamily building with 4 habitable stories (i.e., > three habitable stories) and 10,000 ft² conditioned floor area (CFA). We will show whether PV and BESS are required and illustrate sizing steps. (All steps reference the governing equations and tables in the code.)
Trigger determination:
- Because the building is more than three habitable stories, it falls under the multifamily “more than three stories” rule: PV is required per § 170.2(g) and BESS is required per § 170.2(h) unless an exception applies.
Compute PV (using Equation 170.2‑D: kW PVdc = (CFA × A) / 1000):
- Pick an example PV capacity factor A = 2.21 W/ft² (this is a plausible value for a multifamily >3‑story entry in Table 170.2‑U; use the value from the table that matches your climate zone).
- kW PVdc = (10,000 ft² × 2.21 W/ft²) / 1000 = 22.1 kW dc.
- This exceeds the 4 kW dc small‑system exception, so PV stands.
Check SARA exceptions (quick):
- If your total SARA were < 3% of CFA (i.e., < 300 ft²) or < 80 contiguous ft², you could claim the SARA exception and avoid PV — but in our example SARA is not that small, so exception does not apply.
BESS sizing (Equation 170.2‑E skeleton; use B from Table 170.2‑V):
- From Table 170.2‑V, use a BESS capacity factor B = 1.82 Wh/ft² for “Multifamily > 3 stories” (example table value).
- Compute CFA × B = 10,000 × 1.82 Wh/ft² = 18,200 Wh = 18.2 kWh.
- Equation 170.2‑E then divides by factors including a function of the BESS round‑trip efficiency C (Equation form kWh batt = k × ((CFA × B) / (1000 × C^[0.5])) ). If we assume (for illustration only) a typical round‑trip efficiency C = 0.90 and k = 1.0, then:
- Denominator = 1000 × C^[0.5] ≈ 1000 × 0.949 = 949.
- kWh batt ≈ (18,200 / 949) ≈ 19.2 kWh (minimum rated usable energy capacity).
- This exceeds the 10 kWh BESS exception, so a BESS is required and must be sized accordingly (power capacity then follows Equation 170.2‑G).
- Note: the code gives the exact formula and tables — use the climate‑zone specific A and B values and the actual BESS efficiency and the code’s “k” value for final design. Do not rely on this illustrative numeric assumption for permit submittal.
Summary of example: the 4‑story, 10,000 ft² multifamily building in this example triggers PV (~22.1 kW dc) and a BESS (~19.2 kWh illustrated), and neither of the small‑system exceptions applies. All calculations are based on § 170.2(g) and § 170.2(h) and the tables they reference.
Related provisions
- § 140.10 — Prescriptive PV/BESS requirements for nonresidential & hotel/motel (Table 140.10‑A, equations and BESS provisions).
- § 170.2(g) — Multifamily PV requirements (more than three habitable stories) and SARA rules.
- § 170.2(h) — Multifamily BESS requirements (more than three habitable stories) and sizing equations.
- § 150.1(c)14 — Single‑family PV sizing and exceptions (and PV reduction if paired with BESS).
- Reference Joint Appendix JA11 — PV equipment qualification requirements (referenced by §§ 170.2 and 140.10).
- Reference Joint Appendix JA12 — BESS qualification and cycling capacity requirements (referenced by §§ 140.10, 150.1(c)14, 170.2(h)).
Code references
Grounded in the retrieved California Energy Code — click a citation to read the verbatim passage:
§ 1.27 High relevance — show source text
63|1.27|1.63|1.27|1.63|1.63|1.63|1.63|1.63|1.63|1.63|1.63|1.63|2.46|1.27| |Warehouse|0.39|0.44|0.39|0.44|0.39|0.44|0.44|0.44|0.44|0.44|0.44|0.44|0.44|0.44|0.58|0.39| |Religious Worship|4.25|4.65|3.49|4.52|3.72|4.29|4.64|5.89|5.30|5.67|5.89|4.99|5.78|4.63|7.57|3.90| |Sports & Recreation|2.47|1.97|1.54|2.03|1.60|1.84|1.98|2.63|2.47|2.60|2.75|2.20|2.72|2.15|4.03|1.81| |Multifamily > 3 stories|1.82|2.21|1.82|2.21|1.82|2.21|2.21|2.21|2.21|2.21|2.21|2.21|2.21|2.21|2.77|1.82|
(h) Battery energy storage system (BESS) requirements—more than three habitable stories. All buildings that are required by Section 170.2(g) to have a PV system shall also have a BESS meeting the minimum qualification requirements of Reference Joint Appendix JA12. 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 )
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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.
§ 140.10 High relevance — show source text
(b) Battery energy storage system (BESS) requirements. All buildings that are required by Section 140.10(a) to have a PV system shall also have a BESS meeting the minimum qualification requirements of Reference Joint Appendix JA12. The rated energy capacity shall be not less than the Minimum Rated Useable Energy Capacity determined using Equation 140.10-B or 140.10-C if SARA was used to determine the PV capacity in Section 140.10(a). The rated power capacity shall be not less than the Minimum Power Capacity determined using Equation 140.10-D. 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 140.10-B—BATTERY ENERGY STORAGE SYSTEM MINIMUM RATED USABLE ENERGY CAPACITY kWh batt = [(CFA × B)/(1,000 × C [0.5] )]
EQUATION 140.10-C—BATTERY ENERGY STORAGE SYSTEM MINIMUM RATED USABLE ENERGY CAPACITY, SARA-ADJUSTED kWh batt = [(CFA × B)/(1,000 × C [0.5] )] x (kW PVdc,SARA /kW PVdc )
where:
kWh batt = Minimum Rated Usable Energy Capacity of the BESS in kWh.
CFA = Conditioned floor area that is subject to the PV system requirements of Section 140.10(a) in square feet.
kW PVdc = Minimum Rated PV System Capacity in kW from Equation 140.10-A. kW PVdc, SARA = Minimum Rated PV System Capacity in kW from the SARA calculation. B = BESS Capacity Factor in Wh/square foot as specified in Table 140.10-B for the building type. C = Rated single charge-discharge cycle AC to AC (round-trip) efficiency of the BESS.
EQUATION 140.10-D—BESS MINIMUM RATED POWER CAPACITY
kW batt = kW batt /4
where:
kW batt = Minimum Rated Power Capacity of the BESS in kWdc. kW PVdc = Minimum Rated Useable Energy Capacity of the BESS in kWh. Exception 1 to Section 140.10(b): No BESS is required if the installed PV system capacity is less than 15 percent of the capacity determined by Equation 140.10-A.
Exception 2 to Section 140.10(b): No BESS is required if the rated usable energy capacity determined by Equation 140.10-B or Equation 140.10-C is less than 10 kWh.
Exception 3 to Section 140.10(b): For multitenant buildings, the energy capacity of the BESS shall be based on the tenant spaces with more than 5,000 square feet of conditioned floor area. For single-tenant buildings with less than 5,000 square feet of conditioned floor area, no BESS is required.
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NONRESIDENTIAL AND HOTEL/MOTEL OCCUPANCIES—PERFORMANCE AND PRESCRIPTIVE
COMPLIANCE APPROACHES FOR ACHIEVING ENERGY EFFICIENCY
|TABLE 140.
§ 170.2 High 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 )
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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.
§ 140.10 High relevance — show source text
Exception 1 to Section 140.10(a): 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 140.10(a): No PV system is required where the required PV system capacity is less than 4 kW dc .
Exception 3 to Section 140.10(a): No PV system is required if the SARA contains less than 80 contiguous square feet.
Exception 4 to Section 140.10(a): 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.
Exception 5 to Section 140.10(a): For nonresidential and hotel/motel multitenant buildings, the PV capacity determined by Equation 140.10-A shall be calculated without including tenant spaces meeting all of the following: i. The tenant space is less than or equal to 2,000 square feet of conditioned space; ii. The tenant space is served by an HVAC system that does not serve other tenant spaces in the building; and iii. The tenant space has an individual utility meter to track electricity consumption that does not include the electricity consumption of other tenant spaces in the building.
This exception does not apply where the Commission has approved a community solar program for showing compliance as specified in Title 24, Part 1, Section 10-115, or where a load-serving entity provides a program where PV generation is compensated through virtual energy bill credits for occupants of nonresidential and hotel/motel tenant spaces to receive energy bill benefits from netting of energy generation and consumption.
(b) Battery energy storage system (BESS) requirements. All buildings that are required by Section 140.10(a) to have a PV system shall also have a BESS meeting the minimum qualification requirements of Reference Joint Appendix JA12. The rated energy capacity shall be not less than the Minimum Rated Useable Energy Capacity determined using Equation 140.10-B or 140.10-C if SARA was used to determine the PV capacity in Section 140.10(a). The rated power capacity shall be not less than the Minimum Power Capacity determined using Equation 140.10-D. 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 140.10-B—BATTERY ENERGY STORAGE SYSTEM MINIMUM RATED USABLE ENERGY CAPACITY kWh batt = [(CFA × B)/(1,000 × C [0.5] )]
EQUATION 140.10-C—BATTERY ENERGY STORAGE SYSTEM MINIMUM RATED USABLE ENERGY CAPACITY, SARA-ADJUSTED kWh batt = [(CFA × B)/(1,000 × C [0.5] )] x (kW PVdc,SARA /kW PVdc )
where:
kWh batt = Minimum Rated Usable Energy Capacity of the BESS in kWh.
CFA = Conditioned floor area that is subject to the PV system requirements of Section 140.10(a) in square feet.
§ 170.2 High relevance — show source text
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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 170.2-V—BESS CAPACITY FACTORS (Wh/ft2 of conditioned floor area) Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14 Col15 Col16 Col17 BUILDING TYPE CZ 1 CZ 2 CZ 3 CZ 4 CZ 5 CZ 6 CZ 7 CZ 8 CZ 9 CZ 10 CZ 11 CZ 12 CZ 13 CZ 14 CZ 15 CZ 16 Event & Exhibit 1.82 1.95 1.74 2.12 1.91 2.13 2.24 2.30 2.36 2.47 2.62 2.16 2.64 2.68 3.22 1.89 Library 0.37 7.17 5.97 6.75 5.64 6.08 6.19 7.13 7.18 7.56 7.17 6.93 6.88 6.81 7.93 6.40 Hotel/Motel 0.86 0.84 0.77 0.92 0.81 0.89 0.90 1.01 1.00 1.11 1.14 0.96 1.18 1.18 1.49 0.85 Office, Financial Institution, § 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.
§ 503.1.4. High relevance — show source text
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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.
Exception 5 to Section 170.2(g): Multifamily buildings with more than three habitable stories in areas where a load-serving entity does not provide a program where PV generation is compensated through virtual energy bill credits. This exception does not apply where the Commission has approved a community solar program for showing compliance as specified in Title 24, Part 1, Section 10-115, or where a load-serving entity provides a program where PV generation is compensated through virtual energy bill credits for occupants of nonresidential and hotel/motel tenant spaces to receive energy bill benefits from netting of energy generation and consumption.
TABLE 170.2-U – PV CAPACITY FACTORS (W/ft2 of conditioned floor area) Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14 Col15 Col16 Col17 BUILDING TYPE CZ 1 CZ 2 CZ 3 CZ 4 CZ 5 CZ 6 CZ 7 CZ 8 CZ 9 CZ 10 CZ 11 CZ 12 CZ 13 CZ 14 CZ 15 CZ 16 Event & Exhibit 3.48 4.28 3.66 4.32 3.77 4.05 4.28 4.83 4.63 4. § 150.1 High relevance — show source text
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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SINGLE-FAMILY RESIDENTIAL BUILDINGS—PERFORMANCE AND PRESCRIPTIVE COMPLIANCE APPROACHES
TABLE 150.1-A COMPONENT PACKAGE—SINGLE-FAMILY STANDARD BUILDING DESIGN Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14 Col15 Col16 Col17 BUILDING COMPONENT
ROOFS AND CEILINGSCZ 1 CZ 2 CZ 3 CZ 4 CZ 5 CZ 6 CZ 7 CZ 8 CZ 9 CZ 10 CZ 11 CZ 12 CZ 13 CZ 14 CZ 15 CZ 16 Option B13
Below Roof Deck
Insulation**1,§ 4.44 Medium relevance — show source text
04|4.44|4.95|4.36|5.48|3.38| |Library|0.39|3.23|2.59|3.25|2.48|2.74|3.04|3.49|3.32|3.69|3.79|3.32|3.79|3.37|4.49|2.84| |Hotel/Motel|1.69|1.90|1.66|1.97|1.69|1.87|1.94|2.22|2.09|2.20|2.30|2.05|2.30|2.02|2.72|1.73| |Office, Financial Institution,
Unleased Tenant Space,
Medical Office Building/Clinic|2.59|3.13|2.59|3.13|2.59|3.13|3.13|3.13|3.13|3.13|3.13|3.13|3.13|3.13|3.80|2.59| |Restaurant|8.55|9.32|8.16|9.65|8.21|8.73|9.11|10.18|9.75|10.28|10.85|9.73|10.69|9.73|12.25|8.47| |Retail, Grocery|3.14|3.49|3.01|3.61|3.05|3.27|3.45|3.83|3.65|3.81|4.09|3.64|3.99|3.71|4.60|3.21| |School|1.27|1.63|1.27|1.63|1.27|1.63|1.63|1.63|1.63|1.63|1.63|1.63|1.63|1.63|2.46|1.27| |Warehouse|0.39|0.44|0.39|0.44|0.39|0.44|0.44|0.44|0.44|0.44|0.44|0.44|0.44|0.44|0.58|0.39| |Religious Worship|4.25|4.65|3.49|4.52|3.72|4.29|4.64|5.89|5.30|5.67|5.89|4.99|5.78|4.63|7.57|3.90| |Sports & Recreation|2.47|1.97|1.54|2.03|1.60|1.84|1.98|2.63|2.47|2.60|2.75|2.20|2.72|2.15|4.03|1.81| |Multifamily > 3 stories|1.82|2.21|1.82|2.21|1.82|2.21|2.21|2.21|2.21|2.21|2.21|2.21|2.21|2.21|2.77|1.82|(h) Battery energy storage system (BESS) requirements—more than three habitable stories. All buildings that are required by Section 170.2(g) to have a PV system shall also have a BESS meeting the minimum qualification requirements of Reference Joint Appendix JA12.
§ 140.10 Medium relevance — show source text
EQUATION 140.10-D—BESS MINIMUM RATED POWER CAPACITY
kW batt = kW batt /4
where:
kW batt = Minimum Rated Power Capacity of the BESS in kWdc. kW PVdc = Minimum Rated Useable Energy Capacity of the BESS in kWh. Exception 1 to Section 140.10(b): No BESS is required if the installed PV system capacity is less than 15 percent of the capacity determined by Equation 140.10-A.
Exception 2 to Section 140.10(b): No BESS is required if the rated usable energy capacity determined by Equation 140.10-B or Equation 140.10-C is less than 10 kWh.
Exception 3 to Section 140.10(b): For multitenant buildings, the energy capacity of the BESS shall be based on the tenant spaces with more than 5,000 square feet of conditioned floor area. For single-tenant buildings with less than 5,000 square feet of conditioned floor area, no BESS is required.
146 2025 CALIFORNIA ENERGY CODE
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NONRESIDENTIAL AND HOTEL/MOTEL OCCUPANCIES—PERFORMANCE AND PRESCRIPTIVE
COMPLIANCE APPROACHES FOR ACHIEVING ENERGY EFFICIENCY
TABLE 140.10-A—PV CAPACITY FACTORS (W/ft2 of conditioned floor area) Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14 Col15 Col16 Col17 BUILDING TYPE CZ 1 CZ 2 CZ 3 CZ 4 CZ 5 CZ 6 CZ 7 CZ 8 CZ 9 CZ 10 CZ 11 CZ 12 CZ 13 ** CZ 14** ** CZ 15** ** CZ 16** Events & Exhibits 3.48 4.28 3.66 4.32 3.77 4.05 4.28 4.83 4.63 4.80 5.04 4.44 4.95 4.36 5.48 3.38 Library 0.39 3.23 2.59 3.25 2.48 2.74 3.04 3.49 3.32 3.69 3.79 3.32 3.79 3.37 4.49 2.84 Hotel/Motel 1.69 1.90 1.66 1.97 1.69 1.87 1.94 2.22 2.09 2.20 2.30 2.05 2.30 2.02 2.72 1.73 Office, Financial
Institution, Unleased
Tenant Space, Medical
Office Building/Clinic2.59 3.13 2.59 3.13 2.59 3.13 3.13 3. § 903.2.6. Medium relevance — show source text
For new Group I-4 occupancies, see Exceptions 2 and 3 of Section 903.2.6.
h. New Group R occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.8.
i. See Sections 407.1.1 and 408.1.2 for specific exceptions to construction type, allowable building areas and allowable heights.
j. Restraint shall not be permitted in any building except in Group I-3 occupancies constructed for such use (see Section 408.1.2).
k. Nonambulatory persons shall be limited to the first 2 stories.
l. Nonambulatory persons shall be limited to the first 5 stories.
m.Nonambulatory elderly clients are not permitted in buildings of these types of construction. See Sections 435.3.3 and 435.3.4.
n. In other than Group A, E, H, I, L and R occupancies, high-rise buildings, and other applications listed in Section 1.11 regulated by the Office of the State Fire Marshal, the S increases
for height and stories in Tables 504.3 and 504.4 are permitted in addition to the S area increase in accordance with Table 506.2.
o. For Group R-2 buildings of Type VA construction equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1, S area increase is permit-
ted in addition to the height and story increase provided the height shall not exceed 60 feet and 4 stories.
p. See Section 436.1 for additional regulations for child-care centers and adult day care.|UL = Unlimited; NP = Not Permitted; NS = Buildings not equipped throughout with an automatic sprinkler system; S = Buildings equipped throughout with an automatic sprinkler
system installed in accordance with Section 903.3.1.1; S13R = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.2;
S13D = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.3.
a. See Chapters 4 and 5 for specific exceptions to the allowable height in this chapter.
b. See Section 903.2 for the minimum thresholds for protection by an automatic sprinkler system for specific occupancies.
c. New Group H occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.5.
d. The NS value is only for use in evaluation of existing building height in accordance with the_California Existing Building Code_.
e. New Group I-3 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6.
f. New and existing Group I-2 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6 and Section 1103.5 of the_California_
Fire Code.
g. For new Group I-4 occupancies, see Exceptions 2 and 3 of Section 903.2.6.
h. New Group R occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.8.
i. See Sections 407.1.1 and 408.1.2 for specific exceptions to construction type, allowable building areas and allowable heights.
_j.§ 25.4 Medium relevance — show source text
The interior and exterior cob faces shall be permitted to be unfinished or receive any plaster finish allowed by this appendix.
d.
Cob walls with more than one density shall be built with heavier densities below lighter densities.
e.
Minimum cob wall thickness shall be whichever is greater in Tables BK105.3, BK106.11(1) and BK108.1.
f.
Wall thicknesses less than 10 inches require an engineered design.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound = 0.45 kg, 1 pound per cubic foot = 16.02 kg/m3.
a.
Density is to be measured at equilibrium moisture content. Average wall density shall be within ±5 pcf of the tabulated value.
b.
Requires an approved engineered design per Section BK106.6.
c.
Cob thickness only. The interior and exterior cob faces shall be permitted to be unfinished or receive any plaster finish allowed by this appendix.
d.
Cob walls with more than one density shall be built with heavier densities below lighter densities.
e.
Minimum cob wall thickness shall be whichever is greater in Tables BK105.3, BK106.11(1) and BK108.1.
f.
Wall thicknesses less than 10 inches require an engineered design.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound = 0.45 kg, 1 pound per cubic foot = 16.02 kg/m3.
a.
Density is to be measured at equilibrium moisture content. Average wall density shall be within ±5 pcf of the tabulated value.
b.
Requires an approved engineered design per Section BK106.6.
c.
Cob thickness only. The interior and exterior cob faces shall be permitted to be unfinished or receive any plaster finish allowed by this appendix.
d.
Cob walls with more than one density shall be built with heavier densities below lighter densities.
e.
Minimum cob wall thickness shall be whichever is greater in Tables BK105.3, BK106.11(1) and BK108.1.
f.
Wall thicknesses less than 10 inches require an engineered design.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound = 0.45 kg, 1 pound per cubic foot = 16.02 kg/m3.
a.
Density is to be measured at equilibrium moisture content. Average wall density shall be within ±5 pcf of the tabulated value.
b.
Requires an approved engineered design per Section BK106.6.
c.
Cob thickness only. The interior and exterior cob faces shall be permitted to be unfinished or receive any plaster finish allowed by this appendix.
d.
Cob walls with more than one density shall be built with heavier densities below lighter densities.
e.
Minimum cob wall thickness shall be whichever is greater in Tables BK105.3, BK106.11(1) and BK108.1.
f.
Wall thicknesses less than 10 inches require an engineered design.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound = 0.45 kg, 1 pound per cubic foot = 16.02 kg/m3.
a.
Density is to be measured at equilibrium moisture content.
Frequently asked questions
Who must follow § 170.2(g)/(h) versus § 150.1(c)14?
If the project is a new multifamily building, use § 170.2 (split by story count). If the project is a new single‑family dwelling, use § 150.1(c)14. Nonresidential and hotel/motel follow § 140.10.
When can I avoid installing a BESS even if PV is required?
BESS is not required if the installed PV capacity is less than 15% of the PV capacity produced by the governing equation, or if the computed minimum BESS usable energy is < 10 kWh (other multitenant sizing rules also apply).
Can installing a BESS reduce my required PV?
Yes — for single‑family (§150.1(c)14) and some multifamily provisions, the code allows a 25% reduction in required PV size when a qualifying BESS is installed (BESS must meet JA12 and meet the minimum cycling capacity).
What is SARA and why does it matter?
SARA (solar access roof area) is the roof area that is available for PV (excludes low solar access areas, occupied roofs, or areas excluded by planning/local rules). The PV requirement may be limited by SARA (SARA × 18 or × 14) instead of the CFA‑based equation.
If my calculated PV is 3.5 kW for a commercial tenant space, do I need PV?
No — § 140.10 contains a small‑system exception: no PV is required when the required PV is less than 4 kW dc. Always confirm the applicable exception for the occupancy and whether tenant‑space metering exceptions apply.
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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