| Business | Phone |
| Ambient Temperature Corp 11 River St # 3, Middleton 1949 | (978) 646-0660 |
| Associated Mechanical 4 Bow St, Middleton 1949 | (978) 777-2662 |
| Northern Service Co 5 Gould Rd, Middleton 1949 | (978) 777-3322 |
| Northeast Airheating & Cooling 2 Dixie Dr, Middleton 1949 | (978) 762-4696 |
| Hall Sheet Metal Works Inc 11 River St, Middleton 1949 | (978) 739-3800 |