2025 Title 24 changes: what contractors need to know

By Roman Leonelli · CEO & Certified HERS / ECC Rater · CHEERS Rater #RCN13486 · Published June 10, 2026

The one rule that decides everything: your permit date

The 2025 Energy Code does not apply to a project because of when you build it. It applies because of when you apply for the permit. The California Energy Commission (CEC) states it plainly: “Buildings whose permit applications are applied for on or after January 1, 2026, must comply with the 2025 Energy Code.” Projects with permit applications submitted before that date stay on the 2022 code — all the way through final inspection. Source: the CEC's 2025 Building Energy Efficiency Standards page.

So a permit pulled in December 2025 is a 2022-code job even if you're still hanging drywall in 2027 — and a permit applied for in January 2026 is a 2025-code job even if the plans were drawn in 2024. The 2025 standards were adopted by the CEC on September 11, 2024 and published July 1, 2025 as part of the 2025 Triennial Edition of Title 24 (CEC adoption announcement).

Heat pumps are the prescriptive baseline in all 16 climate zones

The headline change. Under the 2025 code's prescriptive path, single-family space heating must be a heat pump in all 16 California climate zones, or the project must meet the performance requirements of section 150.1(b)1 instead — sections 150.1(c)6–7, per the CEC's official What's New for 2025: Single-Family fact sheet. Under the 2022 code the heat-pump baseline covered only some zones; now it's statewide.

To be clear: this is not a gas ban. A gas furnace can still comply — it just has to go through the performance (energy modeling) path and make up the efficiency difference elsewhere. And like-for-like equipment replacements in existing homes follow the alteration rules, not the new-construction baseline.

Refrigerant charge verification expands

The 2025 code expands refrigerant charge verification — the field test where a certified rater confirms an air conditioner or heat pump holds the factory-correct refrigerant charge. Per sections 150.1(c)6–7 and 150.1(c)15, prescriptive projects now require refrigerant charge verification for heat pumps in all climate zones, and for air conditioners in climate zones 2 and 8 through 15. With heat pumps as the statewide baseline, that means more verification visits on more new systems — plan the rater into your schedule, not after it.

HRV / ERV fault indicators: a new field verification

Heat recovery ventilators (HRVs) and energy recovery ventilators (ERVs) — the balanced-ventilation units that swap heat between exhaust and supply air — must now have a fault indicator display, field-verified by an ECC rater, under section 150.1(c)15. If your design uses an HRV or ERV to meet ventilation requirements, that's one more line on the verification list.

Water heating: gas tankless is out of the prescriptive path

The 2022 code allowed a gas tankless water heater prescriptively in climate zones 3, 4, 13, and 14 when paired with heat-pump space conditioning. The 2025 code removes that exception (section 150.1(c)8) and also removes gas tankless from the prescriptive options for single-family additions (section 150.2(a)1D). The practical result: the heat pump water heater (HPWH) is the prescriptive water-heating baseline, additions included.

Two readiness rules come with it: HPWH installations trigger ventilation and minimum room-volume requirements under section 110.3(c)7B, and HPWH-ready construction requires a minimum 30-amp branch circuit at the water heater location under section 150.0(n)1Ai. We cover the replacement-vs-new-construction details in Does a water heater replacement need a HERS test?

New installer sign-offs on the CF2R

Title 24 compliance runs on three document families: the CF1R (Certificate of Compliance — the design), the CF2R (Certificate of Installation — the installer's sign-off), and the CF3R (Certificate of Verification — the rater's field verification). The 2025 code adds four installer-certified heat-pump control items to the CF2R:

• Defrost delay. Heat pump defrost delay timer set to 90 minutes or more — section 150.0(h)6.
• Supplementary heat lockout. Electric backup heat locked out above 35°F outdoor temperature — section 150.0(h)7.
• Backup heat cap. Electric resistance supplementary heat capped at 2.7 kW per ton of nominal cooling capacity — section 150.0(h)8.
• Thermostat display. Thermostats must display outdoor temperature and indicate when supplementary heat runs — section 150.0(i).

For additions, heating and cooling capacity limits now apply per Tables 150.2-A and 150.2-B, and tested envelope leakage may be used in compliance when field-verified by an ECC rater (section 150.2(a)1E).

LSC replaces TDV: the compliance math changed

Since 2005, performance-path energy models were scored in Time Dependent Valuation (TDV) energy. The 2025 code retires TDV and scores projects on Long-term System Cost (LSC) plus a source-energy budget — Total LSC and Efficiency LSC, per section 150.1(a). For contractors the takeaway is simple: 2022-code energy calcs do not carry over. A project permitted under the 2025 code needs a fresh CF1R run in 2025-approved software, and trade-offs that penciled out under TDV may score differently under LSC.

Multifamily: balanced ventilation becomes mandatory

The big multifamily restructuring (sections 160.x/170.x/180.x and the LMCC/LMCI/LMCV document families) happened in the 2022 code; 2025 builds on it. Per the CEC's What's New for 2025: Multifamily fact sheet:

• Balanced or supply ventilation is mandatory. Exhaust-only systems no longer satisfy whole-dwelling-unit ventilation, and unit compartmentalization is verified by an ECC rater — section 160.2(b)2Aivb.
• Prescriptive HRV/ERV. Balanced systems with heat or energy recovery are prescriptively required for dwelling units in climate zones 1, 2, 4, 11–14, and 16, and all HRV/ERVs need the fault indicator display with ECC-rater verification — section 170.2(c)3B.
• New acceptance testing. Dedicated outdoor air systems (DOAS) and HRV/ERV systems get mandatory acceptance tests — section 160.3(d)1D.
• HPWH-ready everywhere. Dedicated receptacle, condensate drain, designated space, and ventilation for individual dwellings and central systems — sections 160.9(e–f).
• Water heating tightens. Gas tankless removed from prescriptive low-rise individual water heating with 120-volt HPWHs added (section 170.2(d)1); central heat-pump systems follow NEEA Commercial HPWH Tier 2, recirculation needs thermostatic mixing valves above 8 dwellings, and pipe insulation requires ECC-rater verification per RA3.6.3 (section 170.2(d)2).

HERS is now ECC — and CHEERS is the registry

Effective January 1, 2026, the CEC renamed the code-compliance side of the Home Energy Rating System (HERS) program to the Energy Code Compliance (ECC) program: HERS raters become ECC raters, HERS providers become ECC providers, and the field verification and diagnostic testing regulations moved from Title 20 (the CEC's appliance and administrative regulations) into Title 24's administrative part. Per the CEC, projects requiring field verification “must demonstrate compliance to enforcement agencies using compliance documents registered with an Energy Code Compliance (ECC) Provider.” Companies may keep “HERS” in their names, and HERS II whole-house ratings keep the HERS name. Source: the CEC's Energy Code Compliance Program page.

On the registry side: the CEC approved CHEERS as an ECC provider and 2025 Energy Code data registry on November 12, 2025 (it remains approved for 2013–2022 documents too), per the CEC's ECC Providers list. CalCERTS shut down its HERS registry in September 2024, so it is not an option for new documents. ERE registers everything through CHEERS.

What didn't change

• QII. Quality Insulation Installation — the pre-drywall insulation and air-barrier verification — remains a prescriptive requirement per Table 150.1-A, field-verified per Reference Appendix RA3.5 (Energy Code Ace reference). See our QII verification service.
• Duct leakage thresholds. No headline change — duct sealing and leakage testing carry forward from 2022. New allowance: R-4.2 ducts in unvented attics, section 150.0(m)1Bi. Details: duct leakage testing.
• The climate zone map. California keeps the same 16 building climate zones — no boundary changes were made for 2025 (CEC climate zone page).
• The form names. CF1R, CF2R, and CF3R continue for single-family; LMCC/LMCI/LMCV continue for multifamily.

What this means for your next permit

• Check the permit application date first — it decides which code, which software, and which tests apply.
• Bid heat pumps as the default on new prescriptive work; treat gas as a performance-path decision made with the energy consultant, not on site.
• Expect more rater visits per project: refrigerant charge on every prescriptive heat pump, HRV/ERV fault indicators, multifamily compartmentalization, and pipe insulation on central systems.
• Re-run energy models for any design crossing the January 1, 2026 line — TDV numbers don't translate to LSC.
• Make sure your documents land in CHEERS — it's the approved 2025-code registry ERE uses.

ERE Inspections has tested and certified Southern California projects since March 2015. We hold both the HERS and ECC certifications, register through CHEERS, and deliver same-day results across Los Angeles, Orange County, and the Inland Empire. Here's how our Title 24 HERS / ECC testing works — or book a test online.

Frequently asked

Does my project follow the 2022 or the 2025 Energy Code?

It depends on your permit application date, not your construction date. The CEC's rule: buildings whose permit applications are applied for on or after January 1, 2026 must comply with the 2025 Energy Code. If you applied before that date, your project stays on the 2022 code all the way through final — even if construction runs deep into 2026 or 2027.

Does the 2025 Energy Code ban gas furnaces or gas water heaters?

No. The 2025 code makes heat pumps the prescriptive baseline, which means gas equipment no longer complies automatically — but a project can still install gas by using the performance compliance path and making up the difference with other efficiency measures. Like-for-like equipment replacements in existing homes follow the alteration rules and remain legal.

What is an ECC rater — is that different from a HERS rater?

Same job, new name. Under the 2025 code the CEC renamed the code-compliance side of the HERS program to the Energy Code Compliance (ECC) program: HERS raters become ECC raters and HERS providers become ECC providers, effective January 1, 2026. The field tests themselves are unchanged, and companies may keep HERS in their business names. ERE Inspections is certified for both.

Did the duct leakage testing thresholds change in 2025?

No. The CEC's What's New fact sheet lists no change to duct leakage thresholds — the existing duct sealing and testing requirements carry forward from the 2022 code. If you've seen claims that duct leakage is now limited to 5%, that reflects the existing new-duct requirement, not a 2025 change. The one new allowance: R-4.2 ducts are permitted in unvented attics per section 150.0(m)1Bi.

Did QII change under the 2025 code?

No. Quality Insulation Installation (QII) remains a prescriptive requirement verified per Reference Appendix RA3.5 — it applies to new single-family and low-rise multifamily buildings and to additions over 700 square feet, exactly as it did under the 2022 code.

Which registry do I use for 2025 code compliance documents?

CHEERS. The CEC approved CHEERS as an ECC provider and 2025 Energy Code data registry on November 12, 2025, and its registry also remains approved for 2013 through 2022 documents. CalCERTS shut down its HERS registry in September 2024, so don't plan on registering documents there. ERE registers all compliance documents through CHEERS.