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California contractor license

Nielson Mechanical Inc

Nielson Mechanical Inc of Fairfield holds California license 725457 (C20 Warm-Air Heating, Ventilating and Air-Conditioning, C43 Sheet Metal). The CSLB file dated Oct 31, 2026 lists it as active.1 It expires Sep 30, 2028.

Licensed 30 years, longer than 82% of 7,822 active California HVAC contractors.

Active

  • Workers' comp ends Dec 2, 2026 (32 days)

Nielson Mechanical Inc, Fairfield

License
725457
Class
C20 Warm-Air Heating, Ventilating and Air-Conditioning; C43 Sheet Metal
Expires
Sep 30, 2028
Bond
$25,000
Workers' comp
Insured to Dec 2, 2026

CSLB file dated Oct 31, 2026

From the CSLB file dated Oct 31, 2026. Not a consumer report; check the board before you hire.

Has the board taken action on this license?

None in the CSLB file dated Oct 31, 2026. Confirm with the board: CSLB license check

What bond, insurance and workers' comp are on file?

Bond
$25,000Jet Insurance Company, from Jul 28, 2026, continuous
Liability insurance
Not in the CSLB fileCheck with the board
Workers' comp
InsuredInsurance Company Of The West, from Dec 2, 2025, to Dec 2, 2026

Who is on this license?

Responsible managing officer
Matthew J. NielsonSince Jul 26, 1996

What work does this license cover?

Issued Jul 26, 1996. Reissued Sep 30, 2002.

Which other Fairfield businesses hold C20 Warm-Air Heating, Ventilating and Air-Conditioning?

California HVAC contractors

What should you check before hiring?

What to ask before you hire

  1. Ask whether it has been renewed. Something on this license ends within 60 days. Check again before you pay a deposit.
  2. Get the license number in writing. The name on the license should match the name on your contract and invoice.
  3. Check the class covers the job. A license for one trade doesn't cover another. California license classes
  4. Ask for a certificate of insurance sent to you by the insurance agent, not handed over by the contractor. How to read a COI
  5. Ask who will be on site. If a crew works on your property, ask for proof of workers' comp. An exemption on file means the contractor told the CSLB it has no employees.
  6. Put it in a written contract: license number, price, start date and payment schedule. Check the license again on the day you sign.

If the license is lapsed

  1. Don't sign or pay a deposit until the CSLB shows the license active again.
  2. Ask the contractor why. For a bond or insurance lapse, ask for proof that the new bond or policy was filed with the CSLB, then check again.
  3. If work has started, hold further payments, keep the contract, receipts and photos, and file a complaint with Contractors State License Board (CSLB).
  4. Check another contractor. California license lookup

Sources

  1. CSLB License Master (cslb.ca.gov, Oct 31, 2026)
  2. Contractors State License Board (CSLB)