| Air Efficiency Services | Arthur Munoz Jr Navarro | — | (626) 676 4805 | HVAC | Hesperia · San Bernardino County | — | — |
| Air Freeze Refrigeration INC | Robert Raymond Alzaga | — | (909) 465 5991 | HVAC | Chino · San Bernardino County | — | — |
| Air Help | Air Help | info@airhelp.com | (909) 252 1852 | HVAC | Loma Linda · San Bernardino County | — | — |
| Air Management Industries Incorporated | Lloyd Alvin Iii Jackson | — | (909) 945 0041 | HVAC | Rancho Cucamonga · San Bernardino County | — | — |
| Air Masters Systems INC | David Cova Chavez | — | (909) 822 5410 | HVAC | Fontana · San Bernardino County | — | — |
| Air Med Heating & Air Conditioning INC | Erik Lamont Roesberry | — | (909) 364 9833 | HVAC | Chino Hills · San Bernardino County | — | — |
| Air One Heating & A/c INC | Richard Domaciano Jr Lozano | — | (909) 875 5252 | HVAC | Rialto · San Bernardino County | — | — |
| Air Plus Air Conditioning & Heating Services | Michael Nho Tran | — | (909) 917 8121 | Electricians | Chino Hills · San Bernardino County | — | — |
| Air Pro Refrigeration INC | Meza Pena Mauro | airprorefrigerationinc@gmail.com | (760) 686 1414 | HVAC | Victorville · San Bernardino County | — | — |
| Air Repair HVAC | Clayton Roger Siddens | — | (760) 684 3145 | HVAC | Victorville · San Bernardino County | — | — |
| Air Services Mechanical INC | Sandy Dai Pham | — | (714) 989 0314 | HVAC | Redlands · San Bernardino County | — | — |
| Air There | Air There | — | (951) 990 3224 | HVAC | Rancho Cucamonga · San Bernardino County | — | — |
| Air Tight Industries INC | Hector Manuel Armendariz | — | (909) 597 1290 | Other | Chino Hills · San Bernardino County | — | — |
| Air Tyme AC & Heating Service INC | Johnny Joseph Macias | — | (909) 621 1888 | HVAC | Chino · San Bernardino County | — | — |
| Aire Serv Of Upland-north Rancho Cucamonga | Alexander William Weith | — | (909) 296 0669 | HVAC | Rancho Cucamonga · San Bernardino County | — | — |
| Airestream Mechanical INC | John Eastwood Dotter | — | (909) 490 0668 | HVAC | Rancho Cucamonga · San Bernardino County | — | — |
| Airite Heating And Air Conditioning INC | Richard Anthony Jr Mace | — | (909) 628 6035 | HVAC | Ontario · San Bernardino County | — | — |
| Airmax Pros INC | Francisco Cruz Maciel | info@airmaxpros.com | (909) 600 9901 | HVAC | Chino · San Bernardino County | — | — |
| Airpire LLC | German Antonio Jimenez Solano | — | (909) 213 7186 | HVAC | Redlands · San Bernardino County | — | — |
| Airqwest Heating & Air Conditioning | Kevin Herbert Bock | — | (909) 466 1882 | HVAC | Alta Loma · San Bernardino County | — | — |
| Airtong Heating & Cooling | Airtong Heating & Cooling | — | (626) 780 3666 | HVAC | Ontario · San Bernardino County | — | — |
| Airwerks INC | Christopher Lee Miller | — | (951) 751 0481 | HVAC | Chino · San Bernardino County | — | — |
| Aison Commercial INC | Bradley Ryan Brady | — | (909) 310 2708 | GC, remodel, ADU | Rancho Cucamonga · San Bernardino County | — | — |
| Aj & E Renovation | Alex Cornelio Arreola | — | (909) 731 5976 | Other | Rialto · San Bernardino County | — | — |
| Aj Electric And Construction Services INC | Andrew Davis Snyder | — | (909) 825 3147 | Electricians | Grand Terrace · San Bernardino County | — | — |
| Aj Special Coatings INC | Ortega Efrain | — | (760) 646 2815 | Windows, patio, painters | Hesperia · San Bernardino County | — | — |
| Aj Steel Erector INC | Borja Junior Alamilla | — | (714) 720 3988 | Other | Chino · San Bernardino County | — | — |
| Ajay Equipment Corporation | Kyle William Vanderhill | sales@ajayequipment.com | (800) 521 2529 | Other | Chino · San Bernardino County | — | — |
| Ajb Concrete & Masonry Construction | Robert Pedro Flores | — | (909) 644 2013 | Other | Ontario · San Bernardino County | — | — |
| Al 360 Renovations & Construction | Leon Abisai | — | (909) 991 2257 | GC, remodel, ADU | San Bernardino · San Bernardino County | — | — |
| Al Construction & Design | Torres Malacara Alfonso | — | (909) 587 9877 | GC, remodel, ADU | Ontario · San Bernardino County | — | — |
| Alaimo Jason Electric | Jason Thomas Alaimo | — | (909) 241 5827 | Electricians | Rancho Cucamonga · San Bernardino County | — | — |
| Alamitos Electric | Negahdauree Behrooz | — | (949) 337 9792 | Electricians | Yucca Valley · San Bernardino County | — | — |
| Alan Joseph Torres Mendoza | Alan Joseph Torres Mendoza | — | (909) 904 7079 | Other roofers | Fontana · San Bernardino County | — | — |
| Alan L Gotta | Alan L Gotta | — | (909) 793 5659 | GC, remodel, ADU | Redlands · San Bernardino County | — | — |
| Alan Wayne Riggle | Alan Wayne Riggle | — | (909) 981 3501 | GC, remodel, ADU | Mt Baldy · San Bernardino County | — | — |
| Alan William Schenfeld | Alan William Schenfeld | — | (760) 240 6619 | Other | Apple Valley · San Bernardino County | — | — |
| Alan's Residential Services | Alan Albert Leis | — | (909) 730 6686 | GC, remodel, ADU | Upland · San Bernardino County | — | — |
| Alarmco Security Systems | Randall Howard Eason | — | (909) 792 9499 | Electricians | Redlands · San Bernardino County | — | — |
| Alaska Electric | Alaska Sandice | — | (909) 648 0928 | Electricians | Big Bear City · San Bernardino County | — | — |