Licensed Heating & Air Conditioning (C-20) contractors in Castro Valley, CA

The California Contractors State License Board (CSLB) lists 5 Heating & Air Conditioning (C-20) contractors in Castro Valley, California. Each links to a full dossier with license status, insurance, bond, and enforcement — as of October 6, 2026.

5 contractors

1. 4-seasons Heating & Air Conditioning

   Castro Valley, CA · CSLB #962971 · as of October 6, 2026
   Active · clear
2. Affordable Heating And Air Conditioning

   Castro Valley, CA · CSLB #909632 · as of October 6, 2026
   Active · clear
3. Cheng's Mechanical Contractor

   Castro Valley, CA · CSLB #1036153 · as of October 6, 2026
   Active · clear
4. M1 Mechanical Corp

   Castro Valley, CA · CSLB #1129897 · as of October 6, 2026
   Active · clear
5. Specialized Heating & Air Conditioning

   Castro Valley, CA · CSLB #741785 · as of October 6, 2026
   Active · clear

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Data sourced from the California Contractors State License Board (CSLB), current as of October 6, 2026. IsItLicensed is not affiliated with or endorsed by the CSLB or the State of California. Always verify against the official record.