| 1st Gen HVAC LLC | Fredy Jr Ruiz | — | (510) 375 9084 | HVAC | Richmond · Contra Costa County | — | — |
| 411 Heating & AC LLC | Mauluddi Said Opeyany | — | (925) 953 3007 | HVAC | Clayton · Contra Costa County | — | — |
| 99 North General Engineering | Denis Leonid Climov | — | (415) 650 6503 | HVAC | Concord · Contra Costa County | — | — |
| A & R HVAC | A & R HVAC | — | (408) 999 0305 | HVAC | San Ramon · Contra Costa County | — | — |
| A C Heating & Cooling Service INC | Raul Fernando Valderrama | — | (925) 521 1807 | HVAC | Concord · Contra Costa County | — | — |
| A C Systems INC DBA Air Conditioning Systems | Joseph Anthony Allen | — | (925) 676 2103 | HVAC | Concord · Contra Costa County | — | — |
| A G Heating & Air Conditioning | Gil Argueta Garcia | — | (925) 584 0800 | HVAC | Discovery Bay · Contra Costa County | — | — |
| A S A P Heating & Cooling | Curtis Mitchell Orloff | — | (925) 876 1900 | HVAC | Concord · Contra Costa County | — | — |
| A To Z Plumbing & Heating Services INC | Mansour Matthew Azizi | — | (510) 359 8870 | HVAC | Brentwood · Contra Costa County | — | — |
| A V R Heating & Cooling Service | Raul Steve Valderrama | — | (925) 595 2009 | HVAC | Concord · Contra Costa County | — | — |
| A2z Hvacr | A2z Hvacr | — | (925) 550 5719 | HVAC | Concord · Contra Costa County | — | — |
| Abraham K Alvarez | Abraham K Alvarez | — | (925) 339 0343 | HVAC | Danville · Contra Costa County | — | — |
| Absolute Air | Absolute Air | — | (925) 228 8490 | HVAC | Martinez · Contra Costa County | — | — |
| Advanced Control | Advanced Control | info@advancedcontrol.com | (208) 362-5858 | HVAC | Orinda · Contra Costa County | — | — |
| Advanced Equipment Services | Stephen Joseph Rivas | — | (925) 945 7411 | HVAC | Pacheco · Contra Costa County | — | — |
| Air - Con Mechanical Services INC | Joseph Carl Condon | — | (925) 279 3330 | HVAC | Walnut Creek · Contra Costa County | — | — |
| Air Brothers Mechanical INC | Christopher Michael Poshinske | — | (925) 477 8906 | HVAC | Discovery Bay · Contra Costa County | — | — |
| Air Control | James Alan Crowson | interested@domainmarket.com | (925) 938 4822 | HVAC | Lafayette · Contra Costa County | — | — |
| Air Design Heating & Cooling | Air Design Heating & Cooling | — | (925) 837 4328 | HVAC | Danville · Contra Costa County | — | — |
| Air Doctors Heating & Cooling | Air Doctors Heating & Cooling | — | (615) 242-1230 | HVAC | Walnut Creek · Contra Costa County | — | — |
| Air Experts | Byron Eric| Smith Eric Smith | — | (925) 625 5458 | HVAC | Brentwood · Contra Costa County | — | — |
| Air Masters Heating And Air Conditioning INC | Brandon James Gault | — | (925) 855 1560 | HVAC | Discovery Bay · Contra Costa County | — | — |
| Air Mechanics INC | Luis Alonso Colmenares | — | (925) 513 0804 | HVAC | Brentwood · Contra Costa County | — | — |
| Air Men Heating And Air Conditioning | Samuel Sr Arguello | — | (925) 755 9261 | HVAC | Walnut Creek · Contra Costa County | — | — |
| Air Performance Heating & Cooling LLC | John Edward Freij | — | (925) 899 0174 | HVAC | San Ramon · Contra Costa County | — | — |
| Air Pro HVAC | Air Pro HVAC | — | (925) 768 3316 | HVAC | Concord · Contra Costa County | — | — |
| Air Synergy INC | Mendez Alberto | info@airsynergy.com | (925) 510 2037 | HVAC | Pittsburg · Contra Costa County | — | — |
| Air Time Mechanical INC | Robert Edward Elmore | airtimemech@comcast.net | (925) 639 5233 | HVAC | Concord · Contra Costa County | — | — |
| Air Treatment | Air Treatment | — | (416) 235-0373 | HVAC | Walnut Creek · Contra Costa County | — | — |
| Airbee | Jose D Rodriguez | — | (925) 247 8241 | HVAC | Walnut Creek · Contra Costa County | — | — |
| Airflow Specialists | Airflow Specialists | — | (925) 597 0699 | HVAC | Brentwood · Contra Costa County | — | — |
| Airgonomics Heating & Cooling LLC | Charles Edward Gearheart | — | (925) 290 1000 | HVAC | Antioch · Contra Costa County | — | — |
| Albert D Seeno Jr | Albert D Seeno Jr | — | (925) 671 7711 | HVAC | Concord · Contra Costa County | — | — |
| Alco Sheet Metal & Heating INC | Leonard Alfred Farias | — | (510) 432 3028 | HVAC | Alamo · Contra Costa County | — | — |
| Alfa Heating And Cooling | Alfa Heating And Cooling | — | (925) 497 6528 | HVAC | Antioch · Contra Costa County | — | — |
| All Air Heating And Cooling | All Air Heating And Cooling | allairlarryc@gmail.com | (415) 879 1015 | HVAC | Antioch · Contra Costa County | — | — |
| All Bay Heating Air Conditioning & Construction INC | John Daniel Moody | — | (925) 288 9223 | HVAC | Walnut Creek · Contra Costa County | — | — |
| All Star HVAC | All Star HVAC | — | (925) 334 6596 | HVAC | Antioch · Contra Costa County | — | — |
| All Things Good | Martin Alexander Minneboo | — | (510) 778 7001 | HVAC | Richmond · Contra Costa County | — | — |
| All-bay Refrigeration | All-bay Refrigeration | — | (510) 758 1406 | HVAC | El Sobrante · Contra Costa County | — | — |