The 2025 California Energy Code took effect January 1, 2026. If you’re submitting permit applications now, you’re working under new rules — and the gap between what the old code required and what this one demands is significant.
Here’s what changed, what it costs, and what the return looks like.
The Core Shift: Gas Is No Longer the Baseline
The biggest change in the 2025 code is conceptual. Gas systems are no longer the prescriptive baseline for space heating, water heating, or pool heating. Electric heat pumps are. If you want to build with gas systems, you now have to over-compensate through enhanced envelope performance or expanded PV — a difficult and expensive workaround on most projects.
This affects every project type. Single-family residential, multifamily, commercial, healthcare, schools. Heat pumps are now the default. Design your systems around that assumption from day one.
Key HVAC Requirements to Design Around
- Variable-speed heat pumps rated to perform down to 17°F — critical for inland California markets
- End-of-life rooftop HVAC replacement on retail, schools, offices, and libraries must include high-efficiency heat pump systems
- New multizone heat pump baseline for office and school buildings
- Single-zone packaged rooftop units under 65,000 Btuh must meet updated performance criteria
Solar + Battery: Now Mandatory for More Building Types
If your project requires photovoltaic systems under Section 140.10(a), battery energy storage (BESS) is now required alongside it. New building types added to the mandatory PV/BESS list: events and exhibits facilities, religious worship buildings, sports and recreation centers, and high-rise multifamily.
Battery sizing is calculated through one of two methods — equation-based or mixed occupancy. Your energy modeler needs to run these calculations early in design, not at the end.
The financial case for BESS is compelling. Benefits include demand flexibility, grid resilience during California PSPS events, time-of-use optimization, and incentive stacking: SGIP rebates cover up to $1,000/kWh for critical-load storage, and the federal Investment Tax Credit provides a 30% credit through 2032.
Commercial Kitchens: Electric-Ready Is Required
Quick-service restaurants, hotels, schools, and healthcare facilities must now install electrical infrastructure capable of supporting full kitchen electrification — even if you’re initially installing gas appliances. That means adequate panel capacity, conduit pathways to cooking locations, and load calculations accounting for simultaneous electric equipment operation.
For mixed-use or multi-tenant retail developers, build electric kitchen capability into your tenant improvement assumptions now. It’s cheaper to run conduit during shell construction than to retrofit later.
The New Performance Metric: Long-Term System Cost (LSC)
The 2025 code replaces Time Dependent Valuation (TDV) with Long-Term System Cost (LSC) — a 30-year projected present value of costs to California’s energy systems. Your compliance model needs to hit passing scores in three categories: efficiency compliance, total compliance, and source compliance. Run your energy model early with a consultant who understands LSC, not just your architect’s energy compliance check at permit.
The Financial Picture
Initial cost premium for full 2025 code compliance: 2–7% above conventional systems. Here’s the return side:
- Heat pumps achieve 300%+ efficiency vs. 80% for a gas furnace
- LEED-certified buildings command $2.91/sq ft in rental premiums vs. $2.16/sq ft for conventional
- Residential properties with heat pumps show approximately 8% higher resale values
- Federal ITC at 30% through 2032 offsets BESS upfront costs
- TECH Clean California rebates up to $3,000 for heat pump water heaters
Regional Considerations
- Coastal (LA, SD, SF): Moderate year-round temps favor heat pump performance. Watch HPWH placement for humidity.
- Inland Valleys (Sacramento, Fresno, Bakersfield): Cold-climate heat pumps required. Size for 110°F summers and freezing winters.
- Mountain Regions (Tahoe, Big Bear): Specialized equipment rated to 5°F or below is non-negotiable. May require backup electric resistance.
What to Do Right Now
- Confirm your design team has updated their energy compliance models to 2025 code — specifically LSC calculations
- Brief your HVAC engineer on the heat pump baseline requirement and get equipment lead times early — supply chains are tight on cold-climate units
- For commercial projects, have your electrical engineer audit panel capacity and conduit requirements for electric kitchen readiness
- Reserve SGIP rebate allocations before they’re oversubscribed — they’re first-come on a limited budget
The 2028 code development process has already begun at the California Energy Commission. Expect further electrification mandates and embodied carbon tracking requirements. The firms mastering 2025 code now will have a significant lead on whatever comes next.
Part of A Builder’s Life | Sustainability Series
