How to Get an HVAC License in California: The CSLB C-20 Contractor License
By BRIX Editorial Team · Updated
California's HVAC license is the C-20 Warm-Air Heating, Ventilating and Air-Conditioning contractor license from the Contractors State License Board (CSLB). You need four years of experience in the trade, a closed-book C-20 exam plus the Law and Business exam at PSI, a $25,000 bond and workers' comp, which C-20 contractors can't opt out of.
Key takeaways
- The C-20 is a contractor license. California doesn't run a separate state certification for HVAC technicians the way DIR certifies electricians.
- Anyone handling refrigerant still needs federal EPA Section 608 certification.
- C-20 is the only CSLB classification licensed for HVAC system heat pumps; heat pump water heaters can be C-20 or C-36.
- C-20 contractors may not file a workers' comp exemption, even with no employees.
- Costs: $450 application, $200 or $350 initial license, $25,000 bond; renewal every two years at $450 or $700.
Who licenses HVAC work in California?
The Contractors State License Board. Its C-20 classification covers a contractor who "fabricates, installs, maintains, services and repairs warm-air heating systems and water heating heat pumps," plus ventilation and air-conditioning systems with their ducts, registers, flues, controls and filters. It "shall include warm-air heating, ventilating and air-conditioning systems which utilize solar energy."
For the people turning wrenches, the rule that applies statewide is federal: technicians who handle refrigerant need EPA Section 608 certification. We found no state-issued HVAC technician license on CSLB's site. Some cities may have their own rules for mechanical work, so ask the building department where you work.
Who can install heat pumps in California?
This comes up constantly as heat pumps replace gas furnaces. Per CSLB, the C-20 is the classification licensed for HVAC system heat pumps. Heat pump water heaters can be installed by a C-20 (which includes "water heating heat pumps") or a C-36 plumber (which includes "any type of equipment to heat water"). A B General Building contractor may take the prime contract but must subcontract the heat pump work to a C-20 or C-36 unless the job includes two or more unrelated trades. A C-10 electrician can do the panel upgrade but "may not contract for a heat pump water heater or HVAC system heat pump" (CSLB fast facts).
What does a C-20 license require?
| Requirement | Detail |
|---|---|
| Experience | At least 4 years in the classification; up to 3 years of credit for technical training, at least 1 year practical (CSLB) |
| Exams | Law and Business + C-20 trade exam, at PSI, 3½ hours each (CSLB exam FAQ) |
| Trade exam format | Closed book, multiple choice; Planning and Estimating 22%, Fabrication/Installation/Startup 38%, Troubleshooting/Repair/Maintenance 20%, Safety 20% (C-20 study guide) |
| Application fee | $450 (CSLB fees) |
| Initial license fee | $200 sole owner, $350 other entities (CSLB) |
| Renewal (every 2 years) | $450 sole owner, $700 other entities (CSLB fees) |
| Contractor bond | $25,000 (CSLB) |
| Workers' compensation | Required; C-20 contractors "may not submit an exemption" (CSLB) |
How do you get a C-20 license, step by step?
- 1
Get EPA 608 certified and start working
You can't legally handle refrigerant without it. Our EPA 608 Core practice test covers the Core section.
- 2
Build four years of HVAC experience
Experience must be in the C-20 trade at journey level or higher (foreman, supervisor, contractor or owner-builder). Technical training can count for up to three years; at least one year must be hands-on (CSLB). Whoever certifies your experience must have direct knowledge of it.
- 3
Apply to CSLB with the $450 fee
Once CSLB accepts the application, you have 18 months to pass the exams (CSLB exam FAQ).
- 4
Pass Law and Business and the C-20 exam at PSI
Each exam allows 3½ hours. The C-20 exam is closed book and includes load and psychrometric calculations, duct design and Cal/OSHA safety (C-20 study guide). Fail one and you can retake it after 21 calendar days (CSLB exam FAQ).
- 5
Post your bond, prove workers' comp and pay the license fee
After passing you get a bond and fee letter. Post the $25,000 contractor bond, file workers' comp (no exemption for C-20) and pay the $200 or $350 initial fee, which covers two years (CSLB).
Do you need a license for small HVAC jobs in California?
Usually yes. Since January 1, 2025 the minor work exemption covers jobs under $1,000 in labor and materials, but only if the work needs no permit and the unlicensed person hires no workers (CSLB bulletin). Ask the local building department whether an equipment swap needs a permit; if it does, the exemption doesn't apply, no matter how small the job.
Does California accept HVAC licenses from other states?
Partly. CSLB's reciprocal classification list maps Arizona's C-39 and Nevada's C-21 and C-1f air conditioning licenses to the C-20. With reciprocity CSLB "may waive the trade portion of the exam," but you still take California's business law exam (CSLB reciprocity).
Starting your own HVAC company in California
- Workers' comp from day one: C-20 is one of the classifications CSLB won't exempt, so price the policy into your startup budget (CSLB).
- Electrical work: panel upgrades for heat pumps belong to a C-10. See California electrician licensing.
- Taxes: California sales and use tax on equipment you install, and entity filing, are in California contractor taxes and licensing.
- Business setup: trucks, pricing, maintenance plans and first customers are in how to start an HVAC business.
Frequently asked questions
Do you need a license to do HVAC in California?
To contract HVAC work you need a CSLB C-20 Warm-Air Heating, Ventilating and Air-Conditioning license, unless the job qualifies for the under-$1,000 minor work exemption with no permit and no workers. Technicians handling refrigerant also need EPA Section 608 certification.
How long does it take to get a C-20 license?
CSLB requires at least four years of experience in the classification at journey level or above. Up to three years can be credited for technical training, but at least one year must be practical. After CSLB accepts your application you have 18 months to pass the exams.
Is the C-20 exam open book?
No. CSLB's study guide says the C-20 exam is closed book with no reference materials. It's multiple choice, covering planning and estimating, installation and startup, troubleshooting and maintenance, and safety.
Do C-20 contractors need workers' comp in California?
Yes. CSLB lists C-20 among the classifications that may not submit a workers' compensation exemption, so you need a policy or a certificate of self-insurance even if you have no employees.
Who can install a heat pump in California?
CSLB says HVAC system heat pumps fall under the C-20. Heat pump water heaters can be installed by a C-20 or a C-36 plumbing contractor. A general building contractor must subcontract the work unless the job involves two or more unrelated trades.
How much does a California HVAC license cost?
CSLB charges a $450 application fee, a $200 initial license fee for sole owners or $350 for other entities, and active renewals of $450 or $700 every two years. You also need a $25,000 contractor bond and workers' comp.
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Sources
- CSLB — C-20 Warm-Air Heating, Ventilating and Air-Conditioning classification (checked October 24, 2026)
- CSLB — Fast Facts: heat pump water heaters and HVAC heat pumps (checked October 24, 2026)
- CSLB — C-20 examination study guide (April 2026) (checked October 24, 2026)
- CSLB — List of all fees (checked October 24, 2026)
- CSLB — Examinations FAQ (checked October 24, 2026)
- CSLB — Qualifying experience for the examination (checked October 24, 2026)
- CSLB — Issuing my license (bonds, workers' comp) (checked October 24, 2026)
- CSLB — Reciprocal classifications list (checked October 24, 2026)
- CSLB — Minor work exemption rises to $1,000 (AB 2622) (checked October 24, 2026)
- EPA — Section 608 technician certification (checked October 24, 2026)
Change log
- : Page published. C-20 scope, heat pump rules, experience, exam, fees, bond, workers' comp, reciprocity and minor work exemption verified against CSLB.