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Resource · San Diego CountyTitle 24, Part 6 is California's Building Energy Efficiency Code. It applies to your remodel when the project crosses specific thresholds — and three project types reliably cross them.
Title 24 activates based on what your project involves, not just its size.
It covers new construction, additions and alterations — not every project triggers it. Three specific project types reliably cross the threshold: additions over a defined square footage, full HVAC system replacements under the 2026 heat pump mandates, and significant fenestration changes.
When any of these apply, energy compliance documentation becomes a mandatory part of your permit package. In the San Diego metro area that documentation is reviewed by local building departments during plan check. The earlier it's prepared, the fewer delays you face.
Building codes, permit requirements and state housing law are amended on a regular cycle. Confirm current requirements for your parcel with the relevant authority before relying on them for design or budget decisions.
San Diego sits in two separate California climate zones, and each one carries different energy requirements.
Most coastal neighbourhoods — Mission Hills, Point Loma, Pacific Beach, La Jolla, Del Mar — fall within Climate Zone 7. Zone 7's mild marine climate produces temperate conditions year-round, and Title 24's insulation R-values, window performance standards and mechanical efficiency minimums are calibrated accordingly.
Move inland to El Cajon, Santee or Lakeside and the zone changes. Climate Zone 10 experiences wider temperature swings with hotter summers and cooler winters. Zone 10 carries stricter insulation and mechanical requirements because those systems work harder to maintain comfort. A homeowner adding square footage in El Cajon faces different compliance calculations than one doing the same project in Ocean Beach.
The address itself determines which standard applies. Knowing your zone before design is finalized changes what gets specified.
Each trigger activates independently — one is enough.
San Diego room additions that add conditioned floor area must comply with Title 24 when the addition reaches 400 square feet. This requires an energy calculation determining insulation values, window performance specs (U-factor for heat transfer and SHGC for solar control) and mechanical efficiency levels.
Replacing a heating or cooling system activates Title 24 even when no other remodeling work is happening. As of the January 1, 2026 code update, Title 24 strongly favours electric heat pump technology for space and water heating over traditional gas furnaces, and new equipment must meet stringent SEER2 and HSPF2 efficiency minimums.
Replacing your HVAC also triggers mandatory duct leakage testing. A certified HERS rater must pressurize the duct system to prove it leaks less than 15% of total airflow for retrofits, or 5% for new construction. This surprises homeowners because the trigger isn't the remodel — it's the mechanical change itself.
Windows, skylights and glazed doors are regulated by U-factor and SHGC performance standards. Replacing windows across a large portion of a San Diego home triggers a full compliance calculation, confirming the replacements meet Zone 7 or Zone 10 performance minimums rather than basic building code.
Title 24 compliance follows the project through three phases.
Submitted with the permit application. It documents the energy measures the project is designed to include: insulation specs, window ratings, and mechanical equipment efficiency. Getting it right the first time keeps plan check moving.
Filed during construction. The licensed contractor certifies that the measures specified in the CF1R were actually installed in the field.
Filed at final inspection. A HERS rater performs independent field verification covering duct leakage testing, insulation installation confirmation and window performance checks. Without a completed CF3R the project cannot receive final sign-off.
The same requirement plays out differently depending on project type and neighbourhood.
A homeowner in Del Mar adds a 650-square-foot primary suite. Because the home sits in Zone 7, the energy calculation specifies insulation R-values appropriate for a marine climate and replacement windows must meet Zone 7 U-factor standards. The CF1R is prepared before permits submit, the CF2R confirms installation, and a HERS rater visits before final inspection. The permit closes without delay.
A homeowner in El Cajon replaces an aging central air conditioning system. The HVAC trigger activates the 2026 requirements, meaning a high-efficiency heat pump must be installed. Because Zone 10 experiences greater temperature loads, strict duct sealing verification is required. Knowing the trigger existed before the permit was pulled meant the rater visit was already scheduled when work began.
The energy compliance requirement was never news. It was always going to apply.
I'm Joseph Sheiner, founder of Sheiner Construction. Identifying the requirement during design rather than at plan check is what keeps the project on schedule. When the CF1R goes in with the permit application, the local building department has everything needed for a clean review.
We hold CSLB License #1083621. Part of what that means in practice is that before I submit a permit package for any addition or whole-home remodel, I've already checked whether the project crosses a Title 24 threshold. If it does, the CF1R goes in with the application.
If you're planning an addition, HVAC replacement or significant window upgrade, we'll confirm whether Title 24 applies, identify your climate zone, and coordinate the compliance documentation as part of the permit process.
Sheiner Construction · CSLB License #1083621 · Founded 2012 · San Diego, California
