California Solar Mandate for New Homes: Title 24 Requirements, Battery Rules, and What Temecula Buyers Must Know in 2026

California Title 24 Solar Mandate: What It Is and When It Took Effect

California's Title 24, Part 6 Building Energy Efficiency Standards sets the energy performance rules for new construction in the state. The 2019 update, which took effect January 1, 2020, included the first-in-the-nation mandate requiring solar photovoltaic systems on virtually all new single-family and low-rise multifamily residential buildings.

The California Energy Commission adopted the mandate based on a straightforward calculation: solar panels installed at the time of construction are cheaper to incorporate than retrofits added later, and new construction offers the ideal window to right-size the system, orient the roof properly, and pre-wire the electrical infrastructure without the disruption and additional cost of a post-construction installation.

Before the 2020 mandate, solar on new homes was common in California but not universal. Builders often included solar as a selling feature or as a builder upgrade option. After the mandate, it became a non-negotiable compliance requirement similar to insulation R-values or window U-factors. Every permit applicant must demonstrate compliance through the California Energy Commission's compliance software before a building permit is issued.

For homebuyers in Temecula's active new construction market, this means every home built in Wolf Creek, Harveston, Roripaugh Ranch, and the newer communities around Sommers Bend and Altair that received building permits on or after January 1, 2020, came with solar required by law. The mandated solar is included in the base home price in most cases, though the quality, size, and configuration of the system vary significantly by builder.

The key phrase is "meets compliance." The mandate sets a floor, not a ceiling. Builders are required to install a solar system that satisfies the Title 24 energy compliance model. That compliance threshold is calculated on a per-home basis using the CEC's compliance software, and it is not the same as "covers your electricity bill."

The 2023 Title 24 Update: Battery Storage Requirement Added for New Homes

California adopted the 2022 Building Energy Efficiency Standards, effective January 1, 2023, which added a battery storage requirement to the solar mandate. New single-family homes and low-rise multifamily buildings must now include both a solar PV system and a battery energy storage system (BESS) as part of baseline compliance.

The battery requirement was driven by the same logic that produced the solar mandate three years earlier: installing storage at the time of construction is significantly cheaper and simpler than retrofitting it later, and California's grid needs residential storage to manage peak demand during the late afternoon and evening hours when solar production drops and household electricity use peaks.

The compliance minimum battery is not designed to power your home during an outage for any meaningful duration. A 3 kWh battery in a 2,000 square foot Temecula home in July, where air conditioning load can exceed 3 kW, would be depleted in roughly one hour if the AC runs continuously. It provides grid services and TOU rate management value, but buyers expecting real backup resilience should plan to upgrade.

The 2023 standards also tightened the solar sizing formula, added requirements for solar-ready wiring for future expansion, and included provisions for electric vehicle-ready charging infrastructure in garages. These infrastructure provisions are worth knowing because they reduce the cost of future EV charger and solar upgrades.

How the CEC Calculates Minimum Solar System Size

The California Energy Commission determines the minimum required solar system size for a new home using a formula that accounts for several variables. Understanding this formula helps you evaluate whether a builder's proposed system is adequate for your actual needs, not just compliant on paper.

The primary variables in the CEC compliance calculation are the home's conditioned floor area, the climate zone in which the home is located, the orientation and tilt of the roof surfaces available for solar placement, any shading from adjacent structures or vegetation, and whether the home has an attached ADU that is also covered by the same compliance submission.

The compliance formula produces a minimum kWdc (kilowatts direct current) figure. For a typical 2,000 square foot home in Climate Zone 10 with a south-facing roof and no significant shading, the compliance minimum lands in the range of 2.4 to 3.6 kWdc. For a 3,000 square foot home under the same conditions, expect roughly 3.6 to 5.4 kWdc.

The critical point is that this formula targets code compliance, not bill offset. It does not account for your actual electricity consumption, your pool, your electric vehicle, your appliance mix, or your lifestyle. A compliance-minimum system on a 2,200 square foot home with two EVs, a pool, and a spa will cover a small fraction of your annual SCE usage. You will still receive significant monthly SCE bills because the solar produces less than the home consumes.

What Counts as New Construction Under the Mandate

The Title 24 solar mandate applies to new construction as defined by the building permit application date. Any permit for a newly constructed residence submitted on or after January 1, 2020, falls under the 2019 standards with the solar requirement. Any permit submitted on or after January 1, 2023, falls under the 2022 standards with the added battery requirement.

The types of buildings covered include all single-family detached homes, attached townhomes and rowhouses, condominiums in low-rise buildings up to three stories, and modular or manufactured homes placed on permanent foundations. High-rise multifamily buildings of four stories or more follow a different compliance pathway under Title 24's nonresidential provisions and are not subject to the same prescriptive solar requirement, though they face their own energy performance standards.

Additions to existing homes can trigger Title 24 compliance review under certain thresholds. A major addition defined as expanding conditioned floor area by more than 1,000 square feet or adding floor area that increases the home's total size by more than 50 percent may require the entire existing home to be brought into compliance, potentially including the addition of solar. The specific threshold and compliance pathway depend on the size of the addition relative to the existing structure. Homeowners planning significant additions should confirm the compliance trigger with a licensed energy consultant before submitting permit applications.

Rebuilds after a total loss from fire or other casualty are treated as new construction under Title 24 and must comply with the standards in effect at the time the rebuild permit is submitted. This is relevant for homeowners in fire-affected areas of Riverside County who are rebuilding after a total loss.

Exemptions to the California Solar Requirement

The Title 24 solar mandate includes several exemption pathways, but they are narrower than many builders and buyers assume. Knowing which exemptions are legitimate protects you from builders who may claim an exemption simply to avoid the cost of a solar installation.

Any valid exemption claim must be documented in the permit application and supported by a licensed energy consultant's analysis using CEC-approved compliance software. The local building department reviews exemption claims and can reject them if documentation is insufficient. Buyers can request a copy of the Title 24 compliance documentation from the builder as part of the purchase disclosure package.

How Temecula Production Home Builders Handle the Mandate

The major production home builders active in Temecula's new construction corridors, including KB Home, Richmond American, Lennar, Meritage Homes, and William Lyon, handle the solar mandate in one of two ways: builder-owned systems included in the purchase price, or builder-arranged lease or power purchase agreement with a third-party solar company attached to the property at close.

Builder-arranged leases and PPAs are legal and common, but they are not the same as owning the system. When you sign a lease at close, you are agreeing to monthly payments to the solar company for a term that typically runs 20 to 25 years, with escalation clauses that increase the payment rate annually. The system remains the property of the solar company. If you sell the home, the lease transfers to the buyer, which can complicate the sale if the buyer is unwilling to assume the lease obligation.

The clearest outcome for buyers in Temecula's new construction market is purchasing a home where the solar system is included in the purchase price and transfers to you at close with full ownership. In that scenario, you own the system, you control it, you claim the ITC, and you can upgrade or expand it without asking a third party for permission. Confirm the ownership structure in writing before signing any purchase contract.

The Builder Solar Trap: Minimum Systems and Real-World Gaps

The most important thing to understand about builder-installed solar on Temecula production homes is that compliance-minimum does not mean adequate. Builders have a financial incentive to install the smallest system that satisfies the Title 24 compliance software, because every additional watt of solar capacity added at the builder's cost reduces their margin without increasing the sale price in a meaningful way.

In Temecula's active new construction market, a standard compliance-minimum system on a 2,200 square foot home typically runs 2.4 to 3.6 kW DC. At Temecula's solar resource level in Climate Zone 10, a 3 kW system produces approximately 4,500 to 5,400 kWh per year. A 2,200 square foot home with two residents, standard appliances, and central air conditioning in Temecula's climate typically consumes 10,000 to 14,000 kWh per year. The compliance-minimum system offsets 35 to 55 percent of usage at best. Under SCE's NEM 3.0 rate structure, the remaining 45 to 65 percent is purchased from SCE at rates that reach 45 to 55 cents per kWh during peak hours.

At 27 percent solar coverage with SCE's NEM 3.0 rates, the remaining 73 percent of energy is purchased from SCE at current rates. That translates to a monthly SCE bill that can easily run $200 to $350 per month for the unsupported consumption, even with solar on the roof. This is not a hypothetical. It describes the situation many Temecula new construction buyers find themselves in six months after move-in when they add an EV or a pool that was not factored into the builder's minimum compliance calculation.

The solution is to evaluate the system size before closing, not after. Compare the builder's proposed production estimate against your expected usage including all loads you plan to add. If the numbers do not align, negotiate with the builder to upsize the system before close, or budget for a post-close solar expansion within the first year.

Battery Storage Requirements Under 2023 Title 24

The 2022 standards effective January 1, 2023 made California the first state to require battery storage as part of new residential construction compliance. The battery must be a DC-coupled or AC-coupled energy storage system with a minimum capacity determined by the CEC's compliance calculation.

The minimum capacity calculation considers conditioned floor area and climate zone. In Climate Zone 10, which covers most of Temecula, the minimum required battery capacity for a typical production home ranges from approximately 3 kWh for smaller homes to 7 kWh for larger homes. These figures represent the compliance floor, and the same caution about builder minimums applies here as it does to the solar requirement.

A 3 kWh battery in a Temecula home is not a backup power solution in any meaningful sense. At average residential load of 1 to 1.5 kW (excluding air conditioning), a 3 kWh battery provides 2 to 3 hours of essential load coverage. Add the air conditioner and the battery is depleted in under an hour. The compliance battery is designed to participate in grid services programs and to shift some solar production from midday to the SCE peak window. It is not designed to power your home through a wildfire-related shutoff.

The standards require that the battery be capable of communicating with utility demand response programs. This is relevant because SCE's optional demand response programs can provide bill credits in exchange for allowing the utility to temporarily adjust battery dispatch during grid stress events. Your builder should confirm whether the installed battery is enrolled in any demand response program and what the terms are.

If backup power during SCE Public Safety Power Shutoffs is important to your household, plan to upgrade the builder-minimum battery to a system sized for your actual load. In Temecula's fire risk environment, shutoffs lasting 24 to 48 hours are not hypothetical. They have happened in the De Luz Road corridor and in rural areas west of I-15. A compliance-minimum battery provides essentially no meaningful protection in a 24-hour shutoff scenario.

How the Mandate Affects Home Prices in Temecula New Construction Corridors

The solar and battery mandate adds real cost to new home construction. Builders pass that cost to buyers, but the way it shows up in pricing varies significantly. Understanding how builders handle the cost helps you evaluate whether you are getting fair value for the solar system included in your purchase.

In Temecula's major new construction corridors, including Wolf Creek in the south, Harveston near the I-15 and Date Street interchange, the Roripaugh Ranch expansion along Murrieta Hot Springs Road, Sommers Bend east of I-15, and the newer projects around Altair and the emerging neighborhoods near Nicolas Road, the solar mandate adds an estimated $12,000 to $25,000 to builder costs depending on home size and system configuration.

Builders in competitive submarkets like Temecula typically fold the solar cost into the base home price rather than itemizing it as a separate line. This can make it difficult for buyers to assess the true value of what they are receiving. A $15,000 solar system included in a base price of $625,000 is different from a $6,000 minimum-compliance system at the same base price, but both homes appear identical in the listing until you look at the system specifications.

Homes in Harveston and Wolf Creek with compliance-minimum systems sell alongside homes in those same communities with upgraded packages that include 6 to 8 kW systems and full-size batteries. The price difference at close may be $15,000 to $25,000, but the ongoing SCE bill difference can be $150 to $300 per month lower for the larger system buyer. Over ten years, that electricity savings differential ($18,000 to $36,000) exceeds the upfront price difference.

The market is beginning to recognize this. Listings in Temecula's new construction market that specifically call out system size and battery capacity in marketing materials attract more buyer attention than those that list solar generically. As SCE rates continue to increase and new construction buyers become more sophisticated, system size is becoming a meaningful negotiating point at the time of purchase.

Questions to Ask the Builder Before Closing on a New Construction Home with Solar

Most buyers sign a new construction purchase contract without ever asking the right questions about the solar system. The purchase agreement refers to "solar panels" in a sentence or two, and the solar company sends a welcome packet a few days before close. By then, the purchase price is locked and the system is installed. Asking the following questions before signing the purchase agreement gives you negotiating leverage.

When and How to Upgrade the Builder-Installed Solar System

If you have already closed on a new construction home in Temecula with a minimum-compliance solar system and are finding that your SCE bills are higher than expected, upgrading the system is a straightforward path. There are two windows for doing this efficiently.

The best window is before the SCE interconnection agreement is finalized on the original system. In the period between permit issuance and SCE granting Permission to Operate (PTO), some expansion work can be incorporated into the original permit and interconnection application. This window is short, typically 60 to 120 days from close, and requires you to move quickly. If you are still in this window, contact a licensed solar installer immediately for an expansion assessment.

The second option is a post-PTO expansion, which requires a new permit and an amended SCE interconnection application. In Riverside County, the permit process for a solar expansion runs 2 to 4 weeks for plan check approval. The SCE interconnection amendment adds 2 to 6 weeks depending on the current queue. Total timeline from contract to live expanded system: 2 to 4 months in most cases.

The cost of adding solar panels post-close depends on your existing inverter. If the builder installed Enphase microinverters, adding panels means adding microinverters to each new panel, which is modular and clean. If the builder installed a string inverter, the expansion cost depends on whether the existing inverter has unused DC input capacity or whether a second inverter (or a full inverter replacement) is needed.

Adding battery capacity post-close is typically simpler than adding panels because it does not require an SCE interconnection amendment in most configurations. A standalone battery retrofit that operates behind the solar inverter can often be added with only a local Riverside County electrical permit. Confirm with your installer whether your battery addition requires an SCE amendment before you begin the project.

Any expansion that brings your total solar system to a larger size than the originally interconnected capacity will require an SCE interconnection amendment with a system size review. SCE applies a different NEM treatment to expanded systems, and expanding under NEM 3.0 means the entire expanded system is on NEM 3.0 terms. If your original system was grandfathered to NEM 2.0 based on permit and interconnection timing, expanding it under NEM 3.0 after April 2023 may affect that grandfathering status. Confirm with your installer and review SCE's current rules before signing any expansion contract.

Buying vs. Leasing Solar on New Construction: Which Is Standard in Temecula

Among the major builders in Temecula's active production home market, ownership included in the purchase price has become the more common structure, but builder-arranged leases are still used by some builders on some communities. The difference between these two structures is significant enough to affect your decision to buy a particular home.

A lease is not inherently bad. For buyers who cannot use the ITC (those with low federal tax liability), and for buyers who value the maintenance included in the lease, it may be an acceptable arrangement. But it is important to understand what you are signing before close, not after.

The cleanest outcome for most Temecula new construction buyers is full ownership included in the purchase price. If a builder presents a lease as the only option, ask whether an ownership option is available at an upcharge and compare the total cost over ten years between leasing and owning after the ITC.

Federal Tax Credit for Builder-Installed Solar: Who Gets the ITC and How

The 30 percent federal Investment Tax Credit is available to the owner of the solar system in the year the system is placed in service. For new construction homebuyers who take ownership of the solar system at close, the ITC passes to them. Here is how the mechanics work in a typical new construction transaction.

When you purchase a new construction home and the solar system is included in the purchase price, the IRS treats you as the original owner who placed the system in service. The fact that the builder physically installed the system before you took possession does not disqualify you from the credit. What matters is that you are the first user of the system and you own it. The year in which you close on the home and the system is live and operational is the tax year you claim the credit.

The eligible cost for the ITC calculation is the portion of the purchase price attributable to the solar system and battery. If the builder includes the solar as a line item in the purchase agreement, that figure is your ITC basis. If the solar cost is blended into the base home price with no separate line item, you may need to obtain a written statement from the builder allocating a specific dollar amount to the solar installation for tax purposes. Your tax professional will need this documentation.

The ITC is a nonrefundable credit, meaning it reduces your federal tax bill but does not generate a refund if the credit exceeds your tax liability. However, the unused portion carries forward indefinitely until it is fully used. For buyers in the first years of a mortgage with mortgage interest deductions and high income, the $6,000 to $10,000 ITC available on a typical Temecula new construction solar package is typically usable in full within one to two tax years.

If the builder arranges a lease or PPA, the solar company or its investor claims the ITC. In that scenario, the tax benefit flows through the solar company's returns and is reflected in the lease rate they charge you, but it does not appear on your personal tax return. This is a meaningful economic difference that buyers should factor into their evaluation of lease versus ownership.

What Happens at Resale: NEM Status, Warranty Transfer, and Grandfathering

Understanding what happens to the solar system when you eventually sell the home matters both for your own planning and for setting buyer expectations during the sale. There are three dimensions to understand: the NEM interconnection agreement and its transferability, the warranty status of the solar and battery equipment, and any NEM grandfathering protections that may have applied to the original system.

NEM Agreement Transfer

The SCE NEM interconnection agreement is tied to the service address, not the account holder. When you sell the home, the new owner takes over the SCE service account and inherits the existing NEM interconnection. The NEM version (NEM 2.0 or NEM 3.0) transfers with the property. If the original interconnection was established under NEM 2.0 before the April 14, 2023 cutoff and was grandfathered, that NEM 2.0 status typically transfers to the new owner for the remaining grandfathered period (generally 9 years from the original interconnection date, under current SCE rules).

NEM 2.0 grandfathering is a meaningful asset. Homes with NEM 2.0 status sell at a premium in the Temecula market compared to equivalent homes on NEM 3.0, because the export credit rate under NEM 2.0 is substantially higher than under NEM 3.0. If your new construction home's solar was interconnected before April 14, 2023, confirm the exact interconnection date and NEM version with SCE and disclose it prominently in your listing when you sell.

Warranty Transfer

Solar panel manufacturer warranties (typically 25-year product and performance guarantees) generally transfer to subsequent homeowners automatically. The warranty is tied to the product, not the original purchaser, in most manufacturer programs. Inverter warranties (10 to 25 years depending on the brand) and battery warranties (10 to 15 years) typically also transfer with the system. At the time of sale, provide the buyer with all original warranty documentation, equipment serial numbers, and the solar monitoring app credentials so they can register the system in their name.

Disclosure Requirements at Resale

California law requires disclosure of material facts about the property at the time of sale. A solar system on the home, whether owned or leased, is a material fact that must be disclosed. For owned systems, disclose the system size, year installed, equipment brands, warranty status, and current NEM agreement version. For leased systems or PPAs, the full lease or PPA agreement must be disclosed and the buyer must be given the opportunity to review the transfer terms before closing.

The practical takeaway: owned solar with NEM 2.0 status is an asset that adds to home value and attracts buyers. Leased solar with complicated transfer requirements can slow a sale and sometimes requires the seller to pay a buyout to clear the lien before close. Plan accordingly when evaluating the ownership structure at the time of your original purchase.

The 2026 Title 24 Update Outlook: What Changes Are Expected

California's Building Energy Efficiency Standards are updated on a roughly three-year cycle. The current standards (2022 code, effective January 2023) are in effect through the end of 2025. The California Energy Commission is developing the 2025 standards, which are expected to take effect January 1, 2026.

Based on the CEC's publicly available development process and the direction of California energy policy, the 2026 standards are expected to include several meaningful changes for new residential construction buyers and builders.

The 2025 standards rulemaking process is ongoing as of the time of publication. Final adopted standards will be published by the CEC before implementation. Buyers, builders, and solar installers should monitor the CEC's Title 24 rulemaking page for updates.

Frequently Asked Questions: California Solar Mandate for New Homes

Related Resources for Temecula and Riverside County Homeowners

• Solar on New Construction in Temecula: Builder Options and Upgrade Strategies
• Home Battery Storage in California: Costs, Incentives, and Payback for Temecula Homeowners (2026)
• California Solar Incentives in 2026: SGIP, Federal ITC, and Rate Schedules
• Federal Solar Tax Credit Guide for California Homeowners
• Is Solar Worth It in Temecula in 2026? An Honest Assessment
• Get a Solar Quote for Your Home in Temecula or Riverside County