How to Check a Contractor’s CSLB License

Why checking a CSLB license protects your project

Before you let anyone touch your HVAC, electrical, or remodeling work in California, confirm their standing with the Contractors State License Board (CSLB). A verified license helps ensure your contractor is tested, bonded, and in compliance with workers’ compensation rules. It also keeps your permits, warranties, and insurance valid. For HVAC especially, incorrect work can harm indoor air quality, void equipment warranties, and even create safety risks. That’s why many insurance carriers and building departments require a properly licensed contractor for projects at or above California’s legal threshold.

Quick steps to check a CSLB license

Step 1: Gather what you need

• Contractor’s license number (fastest), or
• Business name exactly as it appears on their card or website, or
• Contractor’s personal name as licensed.

Pro tip: Ask for their license number up front. California contractors must include the license number on bids, ads, and contracts over the legal limit.

Step 2: Use the official CSLB license lookup

1. Go to the official CSLB license lookup page (search “CSLB license lookup”).
2. Enter the license number or name.
3. Open the exact matching record—avoid similarly named companies.

A legitimate California contractor license record will show detailed business and classification information. If the contractor avoids giving a number or pushes you toward cash-only deals, consider that a red flag.

Step 3: Read the license record like a pro

• Status: Look for “Active.” “Expired,” “Suspended,” or “Revoked” means stop and investigate. If “Inactive,” they cannot contract for work.
• Classification: For HVAC, look for C-20 HVAC. Many large projects also involve C-10 Electrical or General classifications (B). Match the classification to the scope of your job.
• Qualifier: The responsible managing officer (RMO) or qualifier is the person whose experience backs the license. Make sure there’s a named qualifier and that it matches the company you’re hiring.
• Bond of Qualifying Individual or Contractor’s Bond: California requires a surety bond. The record will show bond status and carrier. No bond, no go.
• Workers’ Compensation: If the contractor has employees, the CSLB record must show an active workers’ compensation policy. “Exempt” means no employees. If you see “Exempt” but there’s a crew on site, that’s a serious compliance issue.
• Personnel/Business Name: The company name on the CSLB record must match the name on your contract, estimate, and invoices.
• Complaints/Disciplinary Actions: Review any citations or accusations. Occasional issues can happen, but unresolved or repetitive problems are warning signs.

Step 4: Cross-check documents and on-site proof

• Contract and invoice must list the exact licensed business name and CSLB number.
• Insurance certificates (workers’ compensation and general liability) should name the same entity as on the CSLB record.
• Permits must be pulled under the same licensed name and classification. For HVAC, permits and inspections help protect performance, code compliance, and warranty coverage.

Red flags and common scams

• Mismatched names: The name on the CSLB page doesn’t match your contract or the truck logo.
• No workers’ comp for a multi-person crew: The record says “Exempt” but multiple techs are on site.
• Cash-only discounts: Pushing you to skip permits or inspections.
• Borrowed license: A real license number used by an unrelated company or person.
• Missing classification: Offering HVAC work without a C-20 HVAC classification.

Remember: Doing major work without proper licensing can void equipment warranties, risk code violations, and jeopardize insurance coverage. Many insurers and lenders require a licensed contractor and final inspections to keep policies valid.

What “licensed and insured” should mean

• Active CSLB license in good standing.
• Correct classification for the scope (for HVAC: C-20 HVAC).
• Current surety bond.
• Workers’ compensation insurance if employees are used.
• Appropriate permit and inspection compliance where required.

Don’t rely on a verbal claim. Verify each item with the CSLB license lookup and request certificates sent directly from the insurer for authenticity.

HVAC-specific tips for your check

• Look for C-20 HVAC on the license record.
• Confirm permits for equipment changes, duct redesign, or electrical upgrades.
• Ask for load calculations, airflow balancing, and duct leakage testing methods—qualified teams will reference standards and manufacturer specs.
• Ensure the installer follows manufacturer installation requirements. Many warranties require licensed contractors and inspections.

When DIY or “handyman” help becomes risky

HVAC systems influence indoor air quality and safety. Improper refrigerant handling, electrical work, or ventilation design can cause performance loss, moisture problems, or health risks. In many jurisdictions, only licensed professionals can legally handle refrigerant or pull mechanical permits. Insurance companies may deny claims if unlicensed work contributes to damage or injury.

Our service area and who we are

#1 AC Guys is a family-owned HVAC engineering team serving Los Angeles County and nearby areas including Orange County, Ventura County, and Western Riverside County. Our fourth-generation family of engineers brings 80+ years of engineering experience to residential and commercial HVAC, with a focus on large and complex projects and a mission of healthy air at home for a healthy life.

Our engineers have trained at the factory with Fujitsu (Japan), Mitsubishi Elektrik (Thailand), Midea (China), Gree (China), and Hier (China). We apply manufacturer specifications on every installation and service call to protect performance, safety, and warranty conditions.

Examples of communities we serve include Los Angeles, Long Beach, Pasadena, Santa Monica, Glendale, Burbank, Torrance, Anaheim, Irvine, Santa Ana, Fullerton, Ventura, Oxnard, Thousand Oaks, Corona, Riverside, and Temecula.

Simple checklist you can save

1. Get the CSLB license number and full business name.
2. Use the CSLB license lookup to confirm active status and the C-20 HVAC classification.
3. Verify surety bond and workers’ compensation status.
4. Match the business name on the CSLB record to your contract, invoices, and permits.
5. Confirm permit and inspection requirements for your project and jurisdiction.
6. Retain documentation for warranties and insurance: contract, permit cards, inspection approvals, and proof of payment.

FAQ

Does every project need a licensed contractor?

California requires a licensed contractor for jobs at or above the legal monetary threshold and for specialty work like HVAC. When in doubt, verify the license and ask your local building department about permits.

What if the license is active but the workers’ comp says “Exempt”?

“Exempt” means the licensed contractor states they have no employees. If a crew shows up, request updated workers’ compensation proof that matches the CSLB record.

What license should an HVAC contractor have?

For HVAC work, look for the C-20 HVAC classification. Large projects may also involve other licensed trades, but the primary HVAC scope should be performed under a C-20 HVAC license.

Verifying a contractor through the CSLB takes minutes and can save you from costly rework, delayed permits, unsafe installations, or denied insurance claims. A clear CSLB record—paired with permits, inspections, and documented manufacturer-compliant installation—supports long-term performance and peace of mind.