CALIFORNIA · hvac
C-20 Warm-Air Heating, Ventilating and Air-Conditioning Contractor
California Contractors State License Board →Scope of Work
A C-20 Warm-Air Heating, Ventilating and Air-Conditioning Contractor fabricates, installs, maintains, services, and repairs warm-air heating systems and water-heating heat pumps, together with the associated ventilation and air-conditioning systems. The scope includes complete systems of ducts, registers, flues, humidity controls, thermostatic controls, and air filters for heating, ventilation, and cooling. Solar-energy equipment integrated with a C-20 system is within scope. Source: CSLB Licensing Classifications Detail, C-20 (https://www.cslb.ca.gov/about_us/library/licensing_classifications/Licensing_Classifications_Detail.aspx?Class=C20).
Experience and Training
4 years (at least 8,000 hours) of full-time, journey-level experience in the HVAC trade within the last 10 years, documented on CSLB Form 13A-11. A qualifying verifier (supervisor, employer, or tradesperson familiar with the work) certifies each employment period. CSLB accepts a mix of direct journey experience and documented apprenticeship or vocational training toward the 4-year total; substitution is capped at 3 years (6,000 hours).
Military Crosswalk
CSLB credits verified military HVAC experience under Business and Professions Code § 115.4 and § 115.5. Military Occupational Specialty (MOS) records, DD-214, and the CSLB Military Service form establish the credit. A spouse of an active-duty service member may qualify for an expedited military spouse license.
Exam
2 exams: Law and Business, and C-20 Trade. Both are administered by CSLB. Core C-20 Trade topics include load calculation, equipment selection and sizing, duct design, refrigeration fundamentals, combustion and venting, controls, Title 24 energy requirements, indoor air quality, and California Mechanical Code compliance. The C-20 exam bulletin on the CSLB site is the current reference for item count and passing score. Federal EPA Section 608 refrigerant certification is required for any technician who opens refrigerant circuits; EPA 608 is separate from the C-20 license and issued by an EPA-approved certifying organization.
Reciprocity
CSLB has written reciprocity agreements with Arizona, Louisiana, Mississippi, Nevada, and North Carolina. Qualifiers from these states may apply without retaking the Trade exam if they have held the equivalent classification for at least 5 of the past 7 years. Source: CSLB Reciprocity (https://www.cslb.ca.gov/Contractors/Applicants/Reciprocity/).
RENEWAL
Active licenses renew every 2 years. Sole-owner active renewal is $450 (2026); non-sole-owner is $700. Delinquent fees apply after expiration, with a 90-day retroactive reinstatement window under SB 1474. CSLB does not require continuing education for license renewal. Source: CSLB General Renewal Information (https://www.cslb.ca.gov/Contractors/Maintain_License/Renew_License/General_Renewal_Information.aspx).
Scope Limitations
The C-20 is issued to a business or qualifying individual. Any electrical work exceeding the incidental connection of HVAC equipment requires a C-10 credential or a partnership with a C-10 licensee. Plumbing beyond condensate drains and gas piping directly serving the HVAC equipment requires a C-36 credential. Refrigerant handling, recovery, and recycling are subject to EPA Section 608 and may require additional state-level reporting for large refrigerant charges under the California Air Resources Board Refrigerant Management Program.
Reciprocity
Accepts from: AZ, LA, MS, NV, NC