- A-C Climate Control Svc
- Air Cool Inc
- Aire Associates
- Airtech Air Conditioning
- Americas Finest Plbg Htg & AC
- Beltsville Heating & AC INC
- Beltsville Heating & Air Cond
- Carrier Mid-Atlantic
- Climate Control Svc Co
- Cropp-Metcalfe Air Cond Htg
- Havtech Corp
- Jolles Brothers Inc
- Melron Cooling & Heating
- Potomac Environmental & Power
- Pro Air Inc
- RCS Commercial Air Cond
- Rjh Air Cond & Refrig Svc
- W E Bowers Assoc Inc
