The short answer: yes, you almost always need a permit to install or replace air conditioning equipment in California. This applies whether you are installing a brand-new system in a home that never had central air, replacing an existing unit, installing a mini-split, or converting from a gas furnace to a heat pump. The permit requirement is not optional and skipping it creates real consequences for both the contractor and the homeowner.
HVAC permits exist because air conditioning installations involve electrical work, structural penetrations, refrigerant handling, and in the case of heat pump systems, significant changes to how a home manages heating and cooling loads. The permit process ensures:
Replacing an existing central air conditioning unit with a new unit of the same type and similar capacity requires a permit in virtually every California jurisdiction. Even a straight equipment swap requires inspection of the electrical connections, refrigerant charge, and compliance with current code requirements that may have changed since the original installation.
Installing a heat pump — including conversions from gas furnaces — requires both a mechanical permit and typically an electrical permit for the new or upgraded circuit. Heat pump water heaters add a plumbing permit to the mix. California's push away from gas appliances under Title 20 and various building electrification ordinances is driving significant heat pump volume and with it, multi-permit complexity.
Ductless mini-split systems require permits in all California jurisdictions. Common exceptions that some contractors mistakenly believe exist (such as units under a certain BTU threshold) are not universally recognized — verify with the specific AHJ before proceeding without a permit.
Installing central HVAC in a home that previously had none requires mechanical, electrical, and in some cases structural permits. The installation typically involves significant work to the home's electrical panel, ductwork, and possibly the roof or walls for equipment placement.
What about portable or window units? Plug-in portable AC units and standard window units installed in existing window openings generally do not require permits in most California jurisdictions. Through-wall units that require cutting a new opening do require permits. When in doubt, call the local building department.
California's Title 24 Building Energy Efficiency Standards apply to HVAC replacements in most circumstances. For residential replacements, this typically means:
The HERS verification step is one of the most common scheduling failures in HVAC contracting. The permit finalizes after the HERS rater signs off, not after the physical installation is complete. Contractors who do not schedule the HERS inspection promptly after installation find their permit stuck open, their crew potentially unavailable to return, and the homeowner's system running without a finaled permit.
InstaPermit monitors HVAC permit status across every California AHJ — approvals, corrections, HERS inspection scheduling, and final sign-off.
Unpermitted HVAC work creates problems that outlast the installation. Homeowners who discover unpermitted HVAC work when selling their home face demands to either pull retroactive permits (which may require exposing completed work for inspection) or price reductions. Insurance claims involving unpermitted HVAC equipment can be denied. And contractors who pull permits for a home discover prior unpermitted work that creates complications for the new permit.
The permit process for HVAC is not burdensome enough to justify the risk of skipping it. For contractors, a permit is also professional protection — it documents that the work was inspected and approved, which is relevant if there is ever a claim about the installation.