California HVAC requirements cover four things at once: habitability (your unit must have permanent heat capable of holding 68°F), licensing (only a C-20 contractor can legally do the work above $500), energy compliance (Title 24 sets minimum SEER2 ratings, MERV 13 filtration, and a heat pump baseline for new construction), and refrigerants (new residential systems installed after January 1, 2026, must use a refrigerant with a global warming potential below 700). Every install, replacement, or major repair also needs a local building permit and, in most cases, third-party HERS verification before the permit closes.
Here is what each of those pieces actually demands.
Heat Is Required. Air Conditioning Isn’t.
Under the Health and Safety Code, a dwelling without functioning heating is a substandard building — one that endangers the life, health, or safety of its occupants.1California Legislative Information. California Health and Safety Code 17920.3 The California Residential Code sets the technical floor: the heating system must hold every habitable room at 68°F or above, measured three feet above the floor and two feet from any exterior wall. The heat source has to be a permanent, fixed installation. Portable space heaters do not count toward that threshold.2International Code Council. 2022 California Residential Code – R303.10 Required Heating
Cooling is different. No state habitability statute requires a landlord to provide or maintain air conditioning. The California Department of Housing and Community Development published a 2025 report recommending a maximum safe indoor air temperature of 82°F for residential units, but that recommendation is not law.3California Department of Housing and Community Development. Policy Recommendations: Recommended Maximum Safe Indoor Air Temperature Some cities have adopted their own heat protections, so check your local municipal code if you rent in a hot climate zone. If a unit came with AC and it breaks, the landlord’s obligation may fall under the general implied warranty of habitability, but the legal footing is much softer than it is for heat.
What Tenants Can Do When Heat Fails
The implied warranty of habitability requires landlords to maintain rentals fit for human occupation, and working heat is part of that standard.4California Department of Real Estate. Tenants Responsibility for Repairs After giving the landlord written notice and a reasonable time to fix the problem, tenants have four options:
- Repair and deduct. Pay for the repair and subtract the cost from rent, up to one month’s rent, usable twice in any 12-month period.
- Rent withholding. Stop paying some or all of the rent until repairs are made, provided the defect threatens health or safety.
- Abandonment. Move out of a seriously defective unit; done properly, no further rent is owed.
- Lawsuit. Sue for damages. Claims under $12,500 can go to small claims court.
Every one of these paths depends on documented notice and a reasonable repair window. Withholding rent without a paper trail is the fastest way to lose an eviction case.
Title 24 Efficiency Minimums for New Equipment
Any new HVAC installation has to meet the Energy Code — Title 24, Part 6 of the California Code of Regulations.5California Energy Commission. Building Energy Efficiency Standards The 2022 standards took effect January 1, 2023, and use the SEER2 and EER2 metrics. Older SEER and EER ratings no longer satisfy compliance for equipment installed after that date.
For residential split-system air conditioners and heat pumps under 65,000 BTU/h, the minimums are:
- Under 45,000 BTU/h: SEER2 of 14.3 and EER2 of 11.7 (or 9.8 for systems rated SEER2 15.2 or higher).
- 45,000 BTU/h and above: SEER2 of 13.8 and EER2 of 11.2 (or 9.8 at SEER2 15.2+).
Heat Pump Baseline for New Construction
The 2022 code shifted the prescriptive baseline for new single-family homes toward heat pumps. Depending on the climate zone, the baseline now assumes a heat pump for either space heating or water heating. Gas equipment is still allowed, but builders have to make up the energy budget elsewhere through the performance compliance path. In practice, all-electric design is the path of least resistance for most new construction.
Thermostats, Ducts, and Air Filtration
Title 24 also covers the parts of a system most homeowners don’t think about. Programmable setback thermostats are required so the system adjusts temperature automatically when the home is unoccupied. Ductwork running through unconditioned attics or crawlspaces needs insulation, generally R-6 or R-8, depending on location and duct type. And new residential construction must use MERV 13 filters on both supply and return air, per Section 150.0(m)12 of the Energy Code.6California Energy Commission. 2019 Whats New for Residential MERV 13 filters capture pollen, mold spores, and smoke particles — a standard that matters more each wildfire season. If you’re retrofitting an older system, confirm the equipment can handle MERV 13 without excessive static pressure, which can damage the blower motor if the system wasn’t designed for denser media.
The 2026 Refrigerant Change
This is the single biggest shift affecting anyone buying a new system. Under the EPA’s Technology Transitions Program (implementing the AIM Act), manufacture of new residential air conditioning products using R-410A was prohibited starting January 1, 2025.7U.S. Environmental Protection Agency. Frequent Questions on the Phasedown of Hydrofluorocarbons An interim rule let equipment manufactured or imported before that date be installed through December 31, 2025. After January 1, 2026, any new residential split system has to use a refrigerant with a global warming potential (GWP) below 700.8U.S. Environmental Protection Agency. Regulatory Actions for Technology Transitions
The replacements are primarily R-454B (GWP 466) and R-32 (GWP 675). Both are classified A2L: low toxicity, mildly flammable. If you replace a complete system in 2026 — both the outdoor condensing unit and the indoor coil — the new equipment has to use one of these lower-GWP refrigerants.7U.S. Environmental Protection Agency. Frequent Questions on the Phasedown of Hydrofluorocarbons
Existing R-410A systems are not affected. You can maintain, repair, and recharge current equipment with R-410A for the life of the system. Replacement components made after January 2025 will be labeled “for servicing existing equipment only,” but they aren’t banned. The phase-out targets new complete systems, not repairs.
Hiring a Licensed Contractor
Performing contracting work totaling $500 or more without a CSLB license is a criminal misdemeanor in California.9Contractors State License Board. California License and Contracting Requirements for Online Home Improvement Marketplace Companies The classification for heating, ventilation, and air conditioning work is C-20, which authorizes fabrication, installation, maintenance, and repair of warm-air heating systems, ventilation systems, air conditioning systems, and all related ductwork, controls, and filters.10Contractors State License Board. C-20 – Warm-Air Heating, Ventilating and Air-Conditioning Contractor
Every licensed contractor carries a $25,000 contractor’s bond to cover consumer losses from incomplete or defective work.11Contractors State License Board. Bond Requirements A contractor with even one employee has to carry workers’ compensation insurance. If that coverage lapses, the license is automatically suspended, and work done while suspended counts as unlicensed work.12Contractors State License Board. Workers Compensation Requirements
A first conviction under Business and Professions Code Section 7028 carries a fine up to $5,000, up to six months in county jail, or both, and penalties escalate on repeat offenses.13California Legislative Information. California Business and Professions Code 7028 The CSLB can also issue civil citations of $200 to $15,000 per offense.9Contractors State License Board. California License and Contracting Requirements for Online Home Improvement Marketplace Companies
Verify a license before signing. The CSLB issues a pocket license card when a license is granted, renewed, or reactivated.14Contractors State License Board. Wall Certificates and Pocket Cards A card alone isn’t proof of current status; a suspended contractor might still hold an expired card. The CSLB’s online “Check a License” tool shows real-time status, bond and insurance dates, and complaint history.
Permits, Compliance Certificates, and HERS Testing
Nearly every residential HVAC installation or replacement in California needs a building permit from the local jurisdiction. The contractor (or the homeowner for owner-occupied property) submits the application with the design-phase compliance documentation and pays the fees. A standard residential HVAC replacement permit typically runs $200 to $500, though fees vary widely across California’s permitting authorities.
California tracks compliance through three certificates that follow the project from design through verification:15California Energy Commission. 2025 Energy Code Compliance Documents – Forms for Single Family
- CF1R, the Certificate of Compliance, generated during design to prove the proposed system meets Title 24.
- CF2R, the Certificate of Installation, completed by the installer to confirm the hardware matches the approved design.
- CF3R, the Certificate of Verification, filled out after a third-party rater conducts field diagnostic testing.
Projects that require field verification must register these forms with an Energy Code Compliance Provider before submitting them to the local building department.15California Energy Commission. 2025 Energy Code Compliance Documents – Forms for Single Family The rater’s testing typically includes a duct leakage test; sealed duct systems must not leak more than 6 percent of fan flow under the California Green Building Code.
Budget for HERS verification separately from the installation cost. Testing alone commonly runs $150 to $500 for a straightforward residential replacement. The CF3R can’t be completed until testing is done, and the permit can’t be finalized without the CF3R. After installation, the local building inspector visits to confirm the equipment matches the permit, checks electrical and gas connections, and reviews the HERS documentation. If anything is off, you get a correction notice and a return visit.
Why Skipping the Permit Costs More Than It Saves
Unpermitted HVAC work usually surfaces at the worst possible moment: a sale, an insurance claim, a warranty call. Most major equipment manufacturers require a permitted installation as a warranty condition, so an unpermitted install can void thousands of dollars of coverage. Insurers can deny claims tied to unpermitted mechanical work, which matters when a bad installation causes water damage, a fire, or a carbon monoxide event.
At sale, home inspectors flag the system and buyers routinely demand corrections or a price cut. Retroactive permitting is possible but rough. You pay the fee, often with a penalty surcharge, then face an inspection that tends to be more thorough than a standard one. If the installation doesn’t meet current code, you’ll have to bring it into compliance before the permit closes, which can mean opening walls or ceilings to reach ductwork or wiring sealed up years earlier.