California Energy Code, Title 24 Part 6
California Title 24 Solar Requirements for New Construction
What the Energy Code requires for solar and battery storage on new homes, multifamily buildings, and commercial buildings, what changed under the 2025 code, and how to keep the requirement from becoming the last obstacle to your Certificate of Occupancy. Written for developers, general contractors, architects, and engineers.
California Title 24 solar requirement: the California Energy Code (Title 24, Part 6) requires newly constructed single-family homes, multifamily buildings, and most nonresidential buildings to install a photovoltaic system sized from the building's floor area, building type, climate zone, and available roof area. Most nonresidential buildings and multifamily buildings of four or more stories must also install battery storage sized to the PV system.
Single-family PV has been required since January 1, 2020. Nonresidential and multifamily PV and battery requirements took effect January 1, 2023 under the 2022 Energy Code. The 2025 Energy Code applies to permit applications filed on or after January 1, 2026, adds building types, and raises several capacity factors.
Summary of published California Energy Commission materials as of October 2026. Requirements depend on building type, climate zone, roof area, and permit timing; the project's energy consultant and the authority having jurisdiction determine final requirements. We verify current requirements for every engagement.
The Last Obstacle
Don't let solar be the last thing standing between your project and its Certificate of Occupancy.
Solar is often treated as something that can be handled late in construction: a subcontract to let after the roof is on, a line to fill when the budget settles. On a California building, that approach collides with the way the Energy Code, the fire authority, the utility, and the building department actually work. The requirement is sized from the building itself, so it is knowable at schematic design. The battery needs a code-compliant home. The utility runs on its own calendar. And the building's final inspection depends on the solar scope being complete, inspected, and documented.
Waiting does not make any of that go away. It compresses it into the weeks when the schedule has the least room.
Fig. 01 / Where solar lands on the construction schedule, by when it was engaged. Illustrative, not to scale.
Bring solar into the project early.
The requirement exists the moment the building program does. Schematic design is when the solar partner should be in the room.
Design it correctly before construction begins.
Roof zones, fire pathways, structural loads, electrical rooms, and the battery location are decided on paper or discovered in the field.
Coordinate with the architect, engineers, GC, and electrical team.
Solar that is coordinated avoids redesigns, change orders, delays, and last-minute surprises. Solar that is not becomes the final obstacle.
What the Code Requires
Requirements by building type.
The Energy Code treats single-family, multifamily, and nonresidential buildings differently. Select a building type to see what applies.
Nonresidential buildings: Section 140.10
Applies to newly constructed buildings where at least 80% of the total floor area, conditioned or not, is in a listed occupancy. Mixed-occupancy buildings qualify when the listed types together reach 80%. Additions, alterations, and unconditioned buildings are not subject to the requirement, except that first-time tenant improvements in unoccupied, previously unused space are.
Listed occupancies. Grocery, high-rise multifamily, office, financial institutions, unleased tenant space, retail, school, warehouse, auditorium, convention center, hotel/motel, library, medical office building/clinic, restaurant, and theater. The 2025 code adds events and exhibits, religious worship, and sports and recreation.
Battery storage. Buildings required to install PV must also install a battery storage system sized to the PV system, unless an exception applies. Batteries must meet Joint Appendix JA12.
Solar-ready. Nonresidential buildings up to three habitable stories, hotels and motels up to 10 stories, and additions adding at least 2,000 square feet of roof must meet solar-ready requirements when PV is not required.
Full guide: Title 24 solar requirements for commercial buildings
Exceptions to the PV requirement
- Solar Access Roof Area less than 3% of conditioned floor area
- Minimum PV system size less than 4 kWdc
- Solar Access Roof Area less than 80 contiguous square feet
- Snow-load conditions as determined by the enforcement authority
- Multi-tenant buildings where the utility offers neither virtual net metering nor community solar
- Under the 2025 code, tenant spaces of 2,000 sq ft or less with a separate meter and HVAC system are excluded from the calculation
Unconditioned warehouses
Not required to install PV or storage. Conditioned warehouses are subject to the requirements.
Multifamily buildings: Section 170.2
Low-rise, three habitable stories or fewer (170.2(f)). A PV system is required, sized as the smaller of Equation 170.2-C (conditioned floor area and dwelling-unit count with climate-zone factors) and the maximum that fits the Solar Access Roof Area. No battery is required, but a battery of at least 7.5 kWh meeting JA12 allows a 25% reduction in required PV.
High-rise, four or more habitable stories (170.2(g) and (h)). A PV system is required where at least 80% of floor area is in listed building types, sized as the smaller of Equation 170.2-D and Solar Access Roof Area at 14 W per square foot. A battery sized to the PV system is also required, with exceptions where installed PV is under 15% of the calculated size or the battery would be under 10 kWh.
Solar-ready and electric-ready. Multifamily buildings up to 10 stories not required to install PV must reserve a solar zone. Dwelling units with gas furnaces, cooktops, or dryers must be electric-ready under Section 160.9.
Full guide: Title 24 solar requirements for multifamily construction
Exceptions
- Low-rise: Solar Access Roof Area under 80 contiguous sq ft, or a minimum system under 1.8 kWdc
- High-rise: Solar Access Roof Area under 3% of conditioned floor area, a minimum system under 4 kWdc, or under 80 contiguous sq ft
- High-rise multi-tenant buildings where the utility offers neither virtual net metering nor community solar
- Snow-load conditions as determined by the enforcement authority
What changes the scope
The story count. Four stories triggers the battery. The roof plan determines whether the requirement fits. The metering strategy determines how the system is wired.
Single-family homes
Newly constructed single-family homes have been required to include a PV system since January 1, 2020, when the 2019 Energy Code took effect. The requirement continues under the 2022 and 2025 codes. The system is sized from conditioned floor area and climate zone and fitted to the solar-accessible roof area.
A qualifying battery can reduce the required PV size, and the 2025 code's expanded heat pump baselines and electric-ready provisions push new homes toward all-electric designs that benefit from storage.
For production homebuilders the requirement is best handled as a plan-type program: standardized layouts per plan and elevation, a standard electrical rough-in, and installations sequenced with closings. See solar for single-family developments and custom and luxury homes.
Exceptions
- Very limited solar-accessible roof area
- Shading conditions that reduce solar access below the threshold
- Community solar alternatives only where the Energy Commission has approved a program for the area
Design implications
Roof planes free of vents and equipment, conduit inside the envelope, panel capacity for the system, and a planned location for inverters and any battery.
2025 Energy Code: in effect for permit applications on or after January 1, 2026
- New listed occupancies for PV and battery requirements: events and exhibits, religious worship, and sports and recreation.
- Higher PV capacity factors for hotel/motel, medical office building/clinic, restaurant, retail, and grocery in all climate zones, and for libraries in Climate Zones 2 through 16.
- Steep-slope roofs now use 18 W per square foot of Solar Access Roof Area; low-slope roofs remain at 14 W per square foot. Mixed roof types are summed.
- Battery equations and capacity factors updated for all building types; schools, offices, financial institutions, unleased tenant spaces, and medical offices in Climate Zone 1 no longer require a battery.
- Small tenant spaces of 2,000 sq ft or less with their own meter and HVAC system in multitenant buildings are excluded from the PV calculation.
- Electric-ready commercial kitchens required for newly constructed quick-service and institutional kitchens under Section 120.6(k).
Which code applies to your project
The code in effect on the date the permit application is filed. Projects permitted in 2023 through 2025 remain under the 2022 code even if they are still under construction. Projects whose applications are filed on or after January 1, 2026 fall under the 2025 code.
Why it matters
On the margin, permit timing changes the required system size, the battery size, and the budget. For phased developments spanning the transition, the program should anticipate both codes.
How Systems Are Sized
Two calculations. The smaller one governs.
For nonresidential buildings the required PV capacity is the smaller of two results. The floor-area method multiplies conditioned floor area by a capacity factor for the building type and climate zone (Equation 140.10-A). The roof-area method multiplies the Solar Access Roof Area by 14 W per square foot on low-slope roofs or 18 W per square foot on steep-slope roofs. High-rise multifamily follows the same logic with its own factors; low-rise multifamily adds a per-dwelling-unit term.
Solar Access Roof Area is the decisive number on most urban and multifamily projects. It includes roofs, covered parking, carports, and new structures capable of supporting PV, and excludes areas with less than 70% annual solar access, areas the building code requires to be kept clear, and areas unavailable for other code reasons. Mechanical equipment, amenity decks, skylights, and fire access pathways all reduce it.
Battery storage is sized from the PV system using building-type energy and power capacity factors, adjusted for round-trip efficiency.
PV may be installed on the Solar Access Roof Area, on the ground on the property, or on a carport on the lot. Under performance compliance, greater building efficiency can reduce the required PV size.
| Building | PV sizing | Battery |
|---|---|---|
| Nonresidential, listed occupancy | Smaller of floor-area method and SARA at 14 W/sq ft (18 W/sq ft steep-slope) | Required, sized to PV |
| Multifamily, 4+ stories | Smaller of Equation 170.2-D and SARA at 14 W/sq ft | Required, sized to PV |
| Multifamily, 1 to 3 stories | Smaller of Equation 170.2-C and SARA capacity | Optional; reduces PV by 25% |
| Single-family | Floor area and climate zone, fitted to roof | Optional; reduces PV |
Mixed-occupancy buildings calculate each occupancy separately and sum the results. Exceptions apply as listed above.
Where Late Solar Goes Wrong
Fifteen things that become expensive when solar waits.
None of these are exotic. Each is a routine coordination item during design and a routine delay during construction.
System design
A roof designed without the array in mind rarely fits the required capacity cleanly. Late design means undersized zones, awkward layouts, or a scramble to add carports.
Electrical coordination
Inverter output, battery interconnection, and metering need panel capacity, breaker space, and room in the electrical room. Discovered late, they mean new gear or rework.
Roof planning
Mechanical equipment, skylights, drains, and fire access pathways placed without the array leave fragmented roof area and a redesign at plan check.
Structural requirements
Array dead loads, canopy columns, and attachment points belong in the structural calculations. Added afterward they mean reinforcement or a smaller system.
Equipment placement
Batteries, inverters, and disconnects need code-compliant locations with clearances, ventilation, and fire department access. Finding one after the walls close is expensive.
Utility coordination
Interconnection applications, metering requirements, and utility inspections run on the utility's calendar. Filed late, they finish late.
Interconnection
Service size, transformer capacity, and export limits can require studies or upgrades. Learning that during construction can delay energization by months.
Permitting
A solar permit filed after the building permit lands behind it in plan check, and comments from the fire authority on the battery can reopen the electrical set.
Inspections
Attachment inspections have to happen before the roof closes; electrical and fire inspections have to close before the building's final. Out of sequence, they stall final sign-off.
Procurement
Batteries, switchgear, and specialty racking carry lead times that can exceed the remaining schedule if ordered late.
Construction scheduling
A solar crew arriving after the roofer, the electrician, and the painter have finished means penetrations through finished work and trades returning to the site.
Title 24 documentation
The compliance forms, the energy model, and the installed system must agree. A mismatch discovered at final inspection means revisions when there is no time for them.
Battery and storage requirements
Most nonresidential and high-rise multifamily buildings now require storage. A battery with no designed location, clearance, or fire review is a common late-stage obstacle.
Final project closeout
Permission to operate, the Certificate of Installation, and commissioning documentation are closeout deliverables. Each has its own dependency chain.
Certificate of Occupancy timing
The building's final inspection typically depends on the solar and storage scope being complete, inspected, and documented. If solar is last, solar is the delay.
Bring Solar In Early
What Eventure does at each phase.
We work alongside the architect, the energy consultant, the engineers, and the general contractor as the solar member of the project team.
Concept
Preliminary sizing, roof and parking strategy, utility territory, budget range.
Design
Energy Code calculation, Solar Access Roof Area analysis, array zones, equipment space.
Engineering
Structural loads, electrical single-line, battery location, fire pathways, single point of coordination.
Title 24 Coordination
Compliance forms aligned with the energy model; PV and battery documented for plan check.
Permitting
Solar and storage submittals move with the building permit; plan check comments closed in one cycle.
Procurement
Modules, inverters, racking, and batteries ordered against the construction schedule with lead times tracked.
Installation
Rough-in with the electrical sub, attachments with the roofer, array and equipment set on sequence.
Utility Coordination
Interconnection application filed during design; metering, witness tests, and permission to operate pursued in parallel.
Inspection
Attachment, electrical, and fire inspections scheduled against milestones; Certificate of Installation completed.
Commissioning
Performance verification, monitoring activated, controls and battery settings confirmed.
Project Closeout
Permission to operate, as-builts, warranties, O&M documentation, and turnover before the Certificate of Occupancy.
The number and the sketch.
The Section 140.10 or 170.2 calculation, the Solar Access Roof Area analysis, array zones, equipment space, and a metering strategy. The architect gets a capacity to design to and a picture of where the system lives.
Loads, rooms, pathways, and the battery's home.
Array layout fixed with mechanical equipment and fire pathways; dead loads to the structural engineer; single-line, inverter, battery, and metering locations to the electrical engineer; battery clearances per the fire authority.
Forms that match, applications filed.
Compliance forms coordinated with the energy consultant so the model, the drawings, and the system agree. Interconnection application filed. Long-lead equipment identified for procurement.
Sequenced, inspected, documented.
Rough-in with the electrical sub, attachments with the roofer, inspections ahead of the building's final, Certificate of Installation, commissioning, and permission to operate delivered with the Certificate of Occupancy.
On the Roof Plan
Solar Access Roof Area is designed, not measured.
The roof a building ends up with is the roof it was drawn with. When the array zones, the fire access pathways, the mechanical equipment with its service clearances, and the conduit route to the electrical room are placed together, the required capacity fits and the installation is clean. When the array is drawn last, it gets what is left.
Fig. 02 / A roof plan drawn with the array: Solar Access Roof Area survives only when pathways, equipment, and conduit are placed together.
We prepare this plan with the architect and the mechanical engineer during design development, and we coordinate the battery and inverter room with the electrical engineer and the fire authority at the same time. How we work with architects and engineers
Documentation and Closeout
The paperwork that stands between the roof and the CO.
Certificate of Compliance
Prepared with the energy consultant and submitted with the permit. Documents the required PV and battery capacity, exceptions claimed, and solar-ready provisions. Must agree with the energy model and the solar drawings.
Certificate of Installation
Completed by the installing contractor after construction, confirming the installed system matches what was permitted. Part of the Energy Code closeout reviewed at the building's final inspection.
Permission to Operate
The utility's authorization to energize, following its review, metering, and inspection. Separate from the building department's process, but owners want it to land at the same time.
Prevailing wage under AB 2143
Nonresidential solar projects served under investor-owned-utility net energy metering or net billing tariffs are treated as public works, with exemptions for single-family homes, residential systems of 15 kW or less, and multiunit housing of two stories or fewer. Labor compliance belongs in the budget from the first estimate.
CALGreen EV requirements
The California Green Building Standards Code sets EV-capable and EV-ready parking requirements for new construction. Canopy and carport design is the natural place to integrate EV infrastructure with the solar scope. EV charging and solar carports
Questions
Title 24 solar, answered.
What is Title 24 and what does it require for solar?
Title 24 is the California Building Standards Code. Part 6, the Building Energy Efficiency Standards or Energy Code, sets energy requirements for new buildings, including photovoltaic systems on new homes, multifamily buildings, and most nonresidential buildings, and battery storage on most nonresidential and high-rise multifamily buildings. The California Energy Commission adopts the Energy Code on a three-year cycle.
When did the Title 24 solar requirement take effect?
The single-family PV requirement took effect January 1, 2020 under the 2019 Energy Code. The nonresidential and multifamily PV and battery requirements took effect January 1, 2023 under the 2022 Energy Code. The 2025 Energy Code applies to permit applications filed on or after January 1, 2026.
Which commercial buildings must install solar under Title 24?
Newly constructed nonresidential buildings where at least 80% of the floor area is in listed occupancies: grocery, office, financial institutions, unleased tenant space, retail, school, warehouse, auditorium, convention center, hotel/motel, library, medical office building/clinic, restaurant, theater, and under the 2025 code, events and exhibits, religious worship, and sports and recreation.
How is the required solar system size calculated?
For nonresidential buildings it is the smaller of a floor-area calculation using building-type and climate-zone capacity factors and a roof-area calculation of 14 watts per square foot of Solar Access Roof Area on low-slope roofs (18 W per square foot on steep-slope roofs under the 2025 code). Multifamily buildings use similar methods with factors tied to floor area and dwelling units.
What is Solar Access Roof Area?
The portion of the roof, covered parking, carports, and other new structures capable of supporting PV that receives at least 70% annual solar access, excluding areas the building code requires to be kept clear and areas unavailable for other code reasons. It is the number that determines whether the required system fits the building, which is why the roof plan matters so much.
Are there exceptions to the Title 24 solar requirement?
Yes. For nonresidential buildings: Solar Access Roof Area under 3% of conditioned floor area, a required system under 4 kWdc, Solar Access Roof Area under 80 contiguous square feet, snow-load conditions, and multi-tenant buildings where the utility offers neither virtual net metering nor community solar. Additions, alterations, and unconditioned buildings are not subject to the requirement, with first-time tenant improvements as an exception.
Does Title 24 require battery storage?
Newly constructed nonresidential buildings that must install PV must also install a battery sized to the PV system, with limited exceptions. Multifamily buildings of four or more habitable stories that must install PV must also install a battery. Low-rise multifamily and single-family buildings may use a battery to reduce the required PV size but are not required to include one.
Which code cycle applies to my project?
The code in effect on the date the permit application is filed. Applications filed on or after January 1, 2026 fall under the 2025 Energy Code; earlier applications fall under the 2022 code. Permit timing on the margin changes required system sizes and should be planned deliberately.
How does Title 24 solar documentation work?
Certificates of Compliance prepared during design document the required PV and battery capacity and are submitted with the permit. Certificates of Installation completed after construction confirm the installed system matches. The installation certificate is part of the Energy Code closeout reviewed before the building's final sign-off.
Can a solar carport satisfy the requirement?
Yes. PV may be installed on the Solar Access Roof Area, on the ground on the property, or on a carport on the lot, and carports and covered parking count toward Solar Access Roof Area.
By Building Type
How Title 24 applies to your project.
Residential & Multifamily
Apartments, condos, mixed-use, affordable, student, senior
All residential & multifamilyCommercial
Office, retail, grocery, hotels, restaurants, healthcare, schools
- Office Buildings
- Corporate Campuses
- Restaurants
- Hotels & Resorts
- Retail & Shopping Centers
- Grocery & Supermarkets
Industrial & Logistics
Warehouses, distribution, cold storage, manufacturing, flex
- Warehouses & Distribution
- Logistics & Fulfillment
- Manufacturing
- Flex Industrial
- Cold Storage
- Food Processing
Technology & Infrastructure
Data centers, tech campuses, laboratories, telecom
All technology & infrastructureParking & Automotive
Parking structures, solar carports, dealerships, fleet depots
All parking & automotiveSpecialty & Institutional
Self-storage, agriculture, wineries, civic, religious, sports
All specialty & institutional
Review Your Title 24 Solar Requirements
Send us your plans. We will tell you what the code requires and when it needs to happen.
A massing study, a schematic set, or a permit set: at any stage we can size the PV and battery requirement, review the roof and electrical approach, and map the steps to a Certificate of Occupancy that does not wait on solar.