C-20 Warm-Air Heating, Ventilating and Air-Conditioning Contractor license in California

Updated November 1, 2026 · Official name from CSLB's classification list

12,227licenses hold C-20
95%Clear (CA addresses)
0.1%workers' comp exempt (all: 49.6%)
100%contractor's bond on file
11.6 yrsmedian time licensed
61%businesses, not sole owners

C-20 is the heating and air-conditioning license. It covers fabricating, installing, maintaining and repairing warm-air heating, ventilation and air-conditioning systems, along with their ducts, registers, flues, filters and humidity and thermostat controls. Water-heating heat pumps and solar-powered HVAC are included.

Since July 1, 2023, a C-20 has needed workers' comp coverage whether or not it hires anyone, one of five classes with that rule. A C-20 record showing an exemption is a red flag; see our workers' comp guide or the work comp suspension page.

Typical work under C-20

Furnace replacement
Central air conditioning and heat pumps
Ductless mini-split systems
Ductwork, registers and returns
Ventilation fans and fresh-air systems
Heat pump water heaters

Work that needs a different license

Boilers and radiators: C-4 Boiler, Hot Water Heating and Steam Fitting
Walk-in coolers and refrigeration below 50 degrees: C-38 Refrigeration
A new 240-volt circuit for the condenser: C-10 Electrical

Tips before hiring

Open the insurance section of the C-20's CSLB record. It should name a workers' comp carrier and policy number.
Ask for a load calculation instead of sizing the new unit to match the old one.
Get the equipment model numbers and efficiency ratings in the contract.
Ask who handles the electrical side if the new system needs a bigger circuit.

Where C-20 contractors are

The cities with the most C-20 license holders in CSLB's current file:

All HVAC contractors lists

Cities with at least 20 C-20 license holders, largest first:

How to verify a C-20 license

Search the business or license number here and confirm C-20 is listed on the profile.
Check the same number on CSLB's Instant License Check.
Read our full guide to checking a contractor license.

Related license types

Source: CSLB public data · Updated November 1, 2026 Status can change at any time. Verify on CSLB's Instant License Check.

More license types: ← C-17 Glazing Contractor · C-21 Building Moving/Demolition Contractor →