| Business | Phone |
| Affordable Heating Cooling 719 Opdyke Ave, Mt. Vernon 62864 | (618) 246-9407 |
| Air Evac Lifeteam 300 Aviation Dr, Mt. Vernon 62864 | (618) 242-8019 |
| Airex Heating & Air Inc 2605 Veterans Memorial Dr, Mt. Vernon 62864 | (618) 242-7900 |
| Allen's Heating & Air Cond 17930 E Fairfield Rd, Mt. Vernon 62864 | (618) 242-2680 |
| Swan Sheet Metal 14547 E Salem Church Rd, Mt. Vernon 62864 | (618) 242-1648 |
| Double Comfort Heating & Air 12018 N Log Cabin Ln, Mt. Vernon 62864 | (618) 242-9660 |
| Eater Heating & Cooling Svc Rr 7 Box 289, Mt. Vernon 62864 | (618) 244-4466 |
| Holloway Heating & Air Cond 1001 Shawnee St, Mt. Vernon 62864 | (618) 242-5481 |
| Lillick Electric Svc Co 415 Cardinal Dr, Mt. Vernon 62864 | (618) 242-5494 |
| Lundius Heating & Cooling 18084 N Old Salem Ln, Mt. Vernon 62864 | (618) 246-1700 |
| J 5 Heating & Refrigerating 1709 Harrison St, Mt. Vernon 62864 | (618) 244-4228 |