TITLE 24 GUIDE · 12 Min Read · Updated October 2026
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SAME ROOFTOP, TWO OUTCOMES
60 units · Los Angeles
115
Common area only
Common area only
Trims the owner’s utility bill. Surplus exported for low credits. Compliance cost
Resident billing
Resident billing
Residents buy solar at a discount. The owner collects every month. Adds to NOI
AT A GLANCE
• Under the 2025 Energy Code, which applies to projects permitted on or after January 1, 2026, solar is required on most new multifamily buildings. Those with four or more stories must also add battery storage.
• These requirements add upfront cost, but the required system doesn’t have to be just an expense. When residents buy its power at a discount to the utility rate, solar becomes recurring income that boosts your property’s NOI.
What is Title 24, Part 6?
California’s Title 24 Building Standards Code sets the rules for how buildings are designed and built across the state. Part 6, the California Energy Code, covers energy efficiency for new and existing residential, multifamily and commercial buildings.
The current edition, the 2025 Energy Code, took effect January 1, 2026. It pushes further on building decarbonization: more efficient heat pumps, electric-ready infrastructure, stronger ventilation standards, and expanded requirements for solar and battery storage.
$4.8B
projected energy cost savings over the code’s lifetime
4M tons
of greenhouse gas emissions avoided, per the CEC
16
building climate zones, each with its own solar factors
Does my project need to comply?
Title 24 applies to newly constructed buildings, additions, alterations and ADUs. The solar and storage mandates, however, apply to new construction. If you’re renovating or re-roofing an existing property, you are not required to add solar. Projects that submit complete permit applications on or after January 1, 2026 follow the 2025 code.
For multifamily buildings, the rules split by height:
Low-rise: 3 stories or fewer
Section 170.2(f). Solar sized by floor area and number of units. Battery optional, and a qualifying one cuts required solar by 25%.
Mid- and high-rise: 4+ stories
Section 170.2(g). Solar sized by floor area. Battery storage required under Section 170.2(h).
Some projects are exempt, usually because the roof can’t hold a meaningful system: the required system would be under 4 kW, there’s less than 80 contiguous square feet of usable roof, or solar would use under 3% of floor area. Even exempt buildings usually must meet solar-ready requirements that reserve roof space and electrical pathways for future solar.
How much solar is required?
Required size depends on your building’s height, conditioned floor area, unit count and climate zone. Under the prescriptive path, the code gives two calculations, and you use whichever produces the smaller system:
METHOD 1
METHOD 1
Conditioned floor area. Floor area × a climate-zone factor. Low-rise buildings also add a per-unit amount for each apartment.
METHOD 2
METHOD 2
Solar access roof area. Usable roof and carport area × 14 W/ft² (low-slope) or 18 W/ft² (steep-slope). Acts as a cap.
TITLE 24 SOLAR CALCULATOR
Estimate your requirement
3 or fewer
4 or more
Climate zone
Zone 9 · Los Angeles, Pasadena
⌄
Floor area (sq ft)
54000
Apartments
60
Estimated required solar
114.7 kW
Solar required
Per apartment 1.91 kW
Battery storage Not required
Is battery storage required?
For buildings with four or more habitable stories, yes. Section 170.2(h) requires a battery sized to the building’s floor area and climate zone, designed to discharge over about four hours. A seven-story, 135,000 sq ft building in San Francisco needs roughly 270 kWh of storage rated at about 67 kW. Very small requirements under 10 kWh are exempt.
For low-rise buildings, a battery is optional. A qualifying battery of at least 7.5 kWh that meets Joint Appendix 12 reduces the required solar by 25%. Batteries also matter financially: solar peaks at midday; demand and prices peak in the evening. A battery stores midday solar and releases it when electricity is most expensive.
What are my options for using solar?
Once you know how much to install, the next question is who uses the power and who keeps the value. That starts with how the utility pays for solar. Most new multifamily projects connect under the Virtual Net Billing Tariff, where owners assign each apartment and common area a share of the system’s output.
Solar used on site
Offsets power residents would otherwise buy at the utility’s time-of-use retail rate. Worth close to full retail.
Solar exported to the grid
Credited hour by hour under the CPUC’s Avoided Cost Calculator. Worth a fraction of retail.
The more of your system’s output the building uses directly, the more value it captures. That’s why the way you deploy solar has such a large effect on returns. There are four common approaches:
Common area only
Solar offsets the owner’s house meter: hallways, lighting, pool, laundry. Common-area accounts generally receive a bill credit at avoided-cost value.
NOI: Low to moderate
Partner: installer
Free power to residents
Solar credits go to residents’ utility accounts at no charge. A leasing amenity, but the property carries the full cost.
NOI: None directly
Partners: installer, utility enrollment
Resident billing + VNBT
Credits go to residents’ accounts; residents pay the owner for their solar share at a discount to the utility rate.
NOI: Moderate to high
Partners: installer, billing provider
Resident billing + behind-the-meter
Master meter with submeters. Solar serves the building directly; residents are billed at or below the utility rate, where metering rules allow.
NOI: Highest
Partners: installer, submetering, billing provider
THE VALUE CASE
How a required solar system adds to NOI
Title 24 decides whether you install solar. What the system does for the property after that is up to you. Set up so residents buy its power, a system you had to build becomes a second income stream alongside rent.
Where the income comes from. Each resident is billed for the solar allocated to their unit at a set discount to the utility’s rate. Residents pay less for electricity; the owner collects every month for power the building was required to generate anyway. Solar serving common areas lowers owner-paid utility expense. Both show up in NOI.
WHY NOI MATTERS MORE THAN THE MONTHLY PAYMENT
$10,000
÷
5%
=
$200,000
Illustrative. Your figures depend on system size, utility rates and the discount you offer residents.
CLIENT STORY
[ADD: Fram client example with real figures: units, system size, annual solar income, resident savings]
What else the system adds
Lower bills for residents
An amenity residents notice every month, which can help leasing and retention.
Income tied to utility rates
Solar charges are set against the utility rate, so income can grow as rates rise.
More value from storage
A battery shifts midday solar to the evening peak instead of exporting it for a low credit.
Tax benefits
Solar that didn’t start construction by July 4, 2026 must generally be in service by end of 2027 for the federal credit. Ask your tax advisor early.
The catch is timing. Resident billing depends on design-stage decisions: how units are metered, which tariff the system enrolls in, and what the lease says about solar. Plan early and every option stays open.
Compliance and timeline
Your energy consultant prepares the compliance documents for the local building department: low-rise projects use LMCC, LMCI and LMCV forms; high-rise projects use NRCC, NRCI and NRCA forms. Certificates must match the permitted plans before final inspection.
1 · Feasibility
Confirm climate zone and permit timing; budget solar and battery.
2 · Design
Choose your solar model and metering approach with your EPC.
3 · Permitting
Submit the Certificate of Compliance with your permit package.
4 · Construction
Install, verify, and file utility interconnection and VNBT enrollment early.
5 · Lease-up and operations
Add solar terms to leases, enroll residents, then bill and collect monthly.
HOW FRAM HELPS
You sell power.
We get you paid.
Once your system is installed, Fram runs the money side: allocating solar value, billing residents, collecting payments and supporting residents, end to end.
Book a call with Fram
See what resident billing could earn on your project.
Frequently asked questions
▸
Does Title 24 require solar on existing apartment buildings?
▸
Is a battery required for multifamily buildings?
▸
What replaced VNEM?
▸
Can I charge residents for solar power?
Sources: California Energy Commission, 2025 Energy Code and 2025 Multifamily Compliance Manual; CPUC, Virtual Net Billing Tariff. This article is for general information and is not legal, tax or engineering advice.
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