| Business | Phone |
| Aire-Flo Heating & Air Cond Columbia 21044 | (410) 761-4440 |
| B & B Air Conditioning & Htg 9687 Gerwig Ln # A, Columbia 21046 | (410) 997-2700 |
| Central Air Cond Contractors 9195 Red Branch Rd, Columbia 21045 | (410) 995-1800 |
| Environmental Systems Assoc 9375 Gerwig Ln # J, Columbia 21046 | (410) 381-7991 |
| R Z Heating & Cooling Columbia 21044 | (301) 596-9074 |
| Supreme Heating & Air Cond Columbia 21045 | (410) 995-6500 |
| Total Environment Corp Columbia 21044 | (410) 884-3655 |
| York International Corp 9055 Guilford Rd # A, Columbia 21046 | (410) 720-6380 |