HVAC Contractors in California

What California changes about replacing heating and cooling

California’s Energy Code, Title 24 Part 6, governs alterations to space conditioning systems. The California Energy Commission states that installation of a space conditioning appliance, other than a plug-in room appliance, requires a building permit, and that field verification and diagnostic testing is prescriptively required for most heating and cooling additions and alterations.

Those tests are carried out by a certified third-party rater, not by the installing contractor, and the results are registered on compliance certificates. Depending on the scope of work and the climate zone, they can include a duct leakage test when heating or cooling components are installed in a ducted system, refrigerant charge verification, and airflow rate verification. Which tests apply is not uniform across the state, so ask which ones your job triggers.

The consumer consequence is straightforward. A California changeout done without a permit skips an independent check that the installer would otherwise have to pass, on ducts, charge and airflow — exactly the things that quietly determine whether a new system performs like the one you paid for. It can also complicate a later home sale, because there is no permit record for the equipment.

California licenses this trade through the Contractors State License Board as classification C-20, warm-air heating, ventilating and air-conditioning. The 2025 Energy Code applies to buildings whose permit applications are filed on or after 1 January 2026, and the standards are revised on a cycle, so confirm the current requirements for your permit date.

How to choose an HVAC contractor in California

Bids for a California changeout are hard to compare because the cheap one is often cheap by leaving out the permit and the verification. Put those items on the table first and the numbers start to mean the same thing.

• Ask whether the bid includes the building permit and the third-party verification, as line items rather than as an assurance.
• Ask which tests your job triggers — duct leakage, refrigerant charge, airflow — since it depends on scope and climate zone.
• Insist on receiving the registered verification certificate at completion. It is the document a future buyer or appraiser will want.
• Verify the C-20 license on the Contractors State License Board register and check it is active.
• Ask for a load calculation rather than a like-for-like swap by tonnage. Oversizing is the most common and least visible installation fault.
• Ask what happens to the ducts. A new condenser on leaky ducts will not deliver what the equipment is rated for.
• Get the manufacturer warranty registration confirmed in writing, since some warranties depend on registration within a window after install.

Questions to ask before you sign a bid

• Does this price include the building permit?
• Does it include third-party field verification, and which tests apply to my job?
• Will I receive the registered compliance certificate when the work is signed off?
• What is your CSLB license number and is it a C-20?
• Did you run a load calculation, or are you matching the size of the old unit?
• What are you doing about the existing ductwork?

General information, not legal or engineering advice. California’s Energy Code is revised on a multi-year cycle and which tests apply depends on your scope of work, climate zone and permit date, so confirm current requirements with your building department or the California Energy Commission.