Solar for New Construction Homes in California: What Buyers Need to Know Before They Close in 2026

California's Title 24 Solar Mandate for New Homes

California's Title 24, Part 6 Building Energy Efficiency Standards is the state's comprehensive code governing energy use in new buildings. The 2019 update, effective January 1, 2020, introduced the first statewide mandate requiring solar photovoltaic systems on new single-family homes, townhomes, and low-rise multifamily buildings up to three stories. California was the first state to require solar on all new residential construction.

The California Energy Commission adopted the rule after concluding that solar installed during construction is 30 to 40 percent cheaper per kilowatt than the same panels added as a retrofit. New construction provides the ideal window: the roof design can be optimized for solar orientation, electrical infrastructure is sized correctly from the start, and the cost is rolled into the construction loan rather than financed separately at post-close rates.

In 2023, California added a second layer to the mandate. The 2022 Title 24 standards, effective January 1, 2023, require battery energy storage systems on most new residential construction in addition to solar. The minimum battery size is calculated by the California Energy Commission's compliance software based on the home's conditioned floor area and climate zone.

The mandate applies to homes receiving building permits on or after the effective date. It does not apply retroactively to existing homes unless a qualifying major addition triggers a full Title 24 compliance review for the entire structure. Additions that exceed 50 percent of the existing conditioned floor area typically trigger full compliance.

What the Mandate Requires vs. What Is Optional

Understanding what is required by law and what is a builder choice is essential before you walk into a sales office.

The law sets a floor. Everything above the floor is where builders make their decisions, and where your negotiating room exists.

Why Builder Solar Is Often Undersized and Overpriced

Builder solar has two consistent problems: it is sized for compliance, not consumption, and it carries a significant markup over what a competitive third-party installer charges for the same hardware.

The Sizing Problem

California's Title 24 compliance software calculates the minimum solar system size using a standardized load profile. That profile assumes average appliance usage for a hypothetical household. It does not account for an EV charger, a pool, a hot tub, an electric dryer, or any other above-average consumption. For a 2,400 square foot home in Temecula's climate zone, the compliance minimum typically lands between 2.4 and 4.0 kW DC.

A real Temecula household with two occupants driving electric vehicles needs 7 to 10 kW of solar to offset combined home and transportation usage. A home with a pool adds another 1.5 to 3 kW of required capacity. The builder's minimum system leaves that gap entirely uncovered, and under NEM 3.0's low export credits, you cannot make it up by selling excess production back to SCE.

The Pricing Problem

Production home builders typically contract solar installation through a preferred vendor or an in-house solar program. That vendor wins the contract through volume pricing, which benefits the builder. The savings are not always passed to the buyer. Builder solar packages in Temecula communities are frequently priced at $4.50 to $6.50 per watt DC installed. Competitive third-party solar installation in Riverside County currently runs $2.80 to $3.80 per watt for equivalent hardware.

On a 3 kW builder system, that pricing gap equals $5,100 to $8,100 in additional cost buried in your home price. On a 5 kW system, the gap widens to $8,500 to $13,500. Because the solar is rolled into your mortgage, the real cost is higher still: at a 7 percent rate over 30 years, an $8,000 solar overpayment costs over $19,000 in total interest.

How to Opt Out of Builder Solar and Use a Third-Party Installer

California law requires the home to have a compliant solar system. It does not require that the builder's preferred vendor install it. In many new construction communities, buyers have the option to opt out of the builder's solar package and coordinate their own installation with a licensed third-party contractor.

The opt-out process works like this. You request a credit from the builder for the solar package value, typically reflected as a reduction in your purchase price or as a credit at closing. You then hire your own California-licensed solar contractor to design, permit, and install a system sized to your actual usage. The third-party installer coordinates the interconnection application with SCE independently.

The timing constraint is the critical complication. Solar installation on a new home generally cannot happen until the home reaches a certain construction stage, often after the roof is complete and the electrical panel is set. There is typically a window of several weeks to several months between when you can install and your planned closing date. A missed installation window can delay your interconnection approval and mean living in the home for months without the solar benefit you planned for.

Not all builders permit opt-outs. Some builders, particularly larger national production builders, bundle the solar into the purchase price as a non-negotiable item. If the builder does not allow an opt-out, your leverage point shifts to negotiating the size and quality of the package, not the installer.

Solar Conduit Pre-Wiring: The $500 Decision That Saves $5,000

One of the highest-value requests you can make during new construction is simple: ask the builder to install solar conduit from the roof to the main electrical panel during the framing stage.

Solar conduit is the empty pipe that solar wiring runs through. When a house is still framed and open, an electrician can route this conduit in a few hours for $500 to $1,500. Once the house is drywalled and finished, routing conduit through interior walls requires opening drywall, patching, repainting, and navigating fireblocking. The same conduit run costs $3,000 to $6,000 after move-in, and it involves weeks of scheduling and living with a construction mess inside a new home.

If the builder is installing solar during construction, conduit is typically included. The issue arises in two scenarios: you opt out of builder solar and plan to install later, or the builder installs the minimum compliant system now and you expect to expand it in the future. In both cases, requesting conduit during framing is cheap insurance.

When making this request, be specific. Ask for conduit from the planned panel locations on the roof to the main electrical panel, with pull strings pre-installed inside the conduit. Also ask for a conduit run from the electrical panel to the garage if you plan to add an EV charger. The garage conduit serves both solar expansion and EV charging infrastructure.

Battery Storage Pre-Wiring During Construction

If you are not purchasing a battery with the builder's solar package, or if you plan to upgrade to a larger battery later, asking for battery pre-wiring during construction follows the same logic as conduit pre-wiring: much cheaper at build time than retrofit.

Battery pre-wiring typically includes conduit from the main panel to a designated battery location, usually in the garage, along with a dedicated breaker slot reserved for the battery system. A complete battery pre-wire kit during construction costs $800 to $1,800 depending on the complexity of the run. Retrofitting the same infrastructure after move-in typically costs $2,500 to $4,500.

Under California's 2023 Title 24 standards, the builder is required to install a minimum battery as part of compliance. That compliance battery is often a 3 to 5 kWh unit sized to meet the formula minimum, not to provide meaningful backup power during an outage. A full-home backup battery capable of running essential loads for 12 to 24 hours typically requires 10 to 15 kWh of storage.

If you plan to upgrade from the builder's compliance battery to a larger unit, ask whether the pre-installed wiring and breaker capacity can support a larger system. Some builders install battery infrastructure sized only for the compliance unit, which means an upgrade requires additional wiring work anyway. Get the specifics in writing.

Sizing for Future EV and Heat Pump Loads

California is phasing out gas appliances in new construction. Starting in 2026, most new homes in California must meet near-zero-emission requirements that effectively require all-electric systems for space heating, water heating, and cooking. New homes in Temecula's most recently permitted communities are already being built electric-only or electric-ready.

This creates a load planning challenge. If your new home has a heat pump for space heating and a heat pump water heater, plus an EV charger, your annual electricity consumption could reach 15,000 to 22,000 kWh per year. A builder minimum solar system producing 4,000 to 5,000 kWh per year leaves a gap of 10,000 to 17,000 kWh that you buy from SCE at peak rates.

The right time to size for these loads is before the solar is installed, not after. Adding three extra panels during the initial installation costs roughly $900 to $1,500 in incremental panel and installation cost. Adding those same panels in a future expansion costs $3,000 to $6,000 after permitting, possible inverter work, and roof access fees.

NEM 3.0 Interconnection for New Construction in California

All new solar systems interconnected with SCE, PG&E, or SDG&E after April 14, 2023, including systems on newly built homes, are placed on NEM 3.0 interconnection. There is no option to interconnect under the old NEM 2.0 program for new applications.

Under NEM 3.0, export credits for solar energy sent to the grid average 4 to 8 cents per kWh depending on the time of day. Under NEM 2.0, export credits matched the retail rate of 25 to 45 cents per kWh during peak hours. The practical result is that NEM 3.0 systems recover their cost through self-consumption, not through grid exports. This fundamentally changes how new construction solar should be designed and sized.

For new construction buyers, the NEM 3.0 timeline adds a layer of complexity. The builder typically submits the interconnection application to SCE during construction. SCE reviews the application, which can take 30 to 90 days from submission of a complete package. If the home is ready for occupancy before SCE approves the interconnection, you move in without solar credits until approval is issued. Ask the builder for the estimated interconnection approval date and whether it will precede or follow your expected closing date.

NEM 3.0 also changes the battery math. Under NEM 2.0, a well-sized solar system without storage could generate credits during the day and draw on those credits at night, effectively using the grid as a free battery. Under NEM 3.0, the low export rates make that strategy expensive. Storing solar production in a battery and discharging it during SCE's peak rate period, typically 4 pm to 9 pm, is now the economically correct behavior. New construction homes that include a battery from day one are better positioned for NEM 3.0 economics than those relying solely on a solar array.

New Construction Solar vs. Retrofit: Key Differences

Installing solar on a new home during construction is technically and economically different from a post-construction retrofit. Understanding the differences helps you evaluate what the builder is offering and what you might gain by coordinating your own installation.

The core difference between new construction and retrofit solar is when the decisions get made. In a retrofit, you control every decision: system size, equipment brand, installer, financing structure. In new construction, many of those decisions are made by the builder before you even sit down with the sales agent. Your job is to reclaim those decisions before you sign, not after you close.

Temecula New Construction Communities and Builder Solar Programs

Temecula and its surrounding areas have several active new construction communities, each with different builder solar approaches.

Questions to Ask Your Builder About Solar Before You Sign

Walk into any new construction sales office with this list. Get every answer in writing, either in the purchase contract or in a written addendum signed by the builder's representative.

Frequently Asked Questions