What do California HVAC rules require?

California HVAC rules require 4 things: Title 24 energy code compliance, a mechanical permit, a C-20 contractor license and EPA-certified refrigerant handling.

Key takeaways

Verify the license

the C-20 classification covers warm-air heating, ventilating and air-conditioning work.

Pull the permit

the City of San Diego requires a mechanical permit to install, alter, replace or repair HVAC systems.

Test the ducts

kept ducts are tested to no more than 10% total leakage or 7% leakage to outside.

Confirm the refrigerant certification

technicians who service equipment holding refrigerant hold an EPA Section 608 certification.

What does Title 24 require for an HVAC replacement?

According to California Energy Commission research from the 2025 Energy Code (Title 24, Part 6), effective January 1, 2026, replacing the outdoor unit or the indoor unit of a split system triggers duct sealing and field verification. There are 2 requirements.

Duct leakage testing

When a space conditioning system is altered, the duct sealing requirements apply. Kept ducts are tested by the installer and an ECC-Rater to no more than 10% total leakage or 7% leakage to outside, and a smoke test with visual verification is the fallback when the leakage target is not met.

Third-party verification (HERS)

An ECC-Rater performs the field verification and diagnostic testing. Effective January 1, 2026, the HERS program no longer supports an Energy Code compliance demonstration, and the field verification provisions sit in the Energy Code.

Does an HVAC replacement need a permit in San Diego?

According to City of San Diego research from the Development Services Department, Mechanical Permit page, confirmed October 17, 2026, no part of a heating, ventilating, air conditioning or refrigeration system is installed, altered, replaced or repaired without a mechanical permit. The Development Services fact sheet When is a Permit Required? states that maintenance repairs under $1,000 involving like-for-like replacements are exempt. Furnace replacements and forced-air or AC unit installations in single-family homes, townhomes and duplexes qualify for a simple no-plan permit, except on historic or potentially historic properties. Other cities in San Diego County issue city permits.

What license does an HVAC contractor need in California?

According to Contractors State License Board research from the Construction Project Checklist, December 2024, contractors hired for work that costs $1,000 or more in labor and materials hold a CSLB license. Any project that needs a permit or workers requires a licensed contractor. The C-20 classification covers warm-air heating, ventilating and air-conditioning systems, including the ducts, registers, thermostatic controls and air filters connected to those systems. A San Diego resident checks a license number with the License Check feature on the CSLB website.

What certification does refrigerant handling require?

According to U.S. Environmental Protection Agency research from the Section 608 Technician Certification program, March 23, 2026, technicians who maintain, service, repair or dispose of equipment that could release refrigerants hold Section 608 certification, and the certification extends to appliances containing most substitute refrigerants, including HFCs. The refrigerant phase-out is covered in Why Is My AC Not Cooling?

What should a San Diego home owner check before hiring an HVAC contractor?

A San Diego home owner checks 6 items before hiring an HVAC contractor:

Verify the license status

The CSLB License Check shows whether the C-20 license is active.

Confirm the liability insurance

General liability insurance covers accidental damage to the property.

Confirm the workers' compensation coverage

Active C-20 contractors carry workers' compensation insurance or a certificate of self-insurance, whether or not the contractor has employees.

Confirm the permit responsibility

The contractor pulls the permits and schedules the inspections.

Confirm the Title 24 testing in the quote

The quote lists the duct testing and the field verification.

Verify the written warranty

The warranty terms are written in the contract.

Schedule San Diego HVAC Installation Service Today

No matter the HVAC issue, Sandiego HVAC Services has the solution for San Diego residents. Call +1 (858) 392-9754 or send the service request form with name, phone, ZIP or neighborhood and system type. See also AC Installation and Replacement in San Diego, Heat Pump Installation in San Diego and How Much Does HVAC Cost in San Diego?