❄️ Official Rankings
10 Best HVAC in O'Fallon, MO (August 2026)
We compared 10 hvac serving O'Fallon and Saint Charles County, Missouri, and ranked the top providers by verified reviews, ratings, and local reputation — 6,720 customer reviews in all.
The 10 listed below hold an average rating of 4.9 out of 5, led by Stay Cool Climate Control. Updated for August 2026.
- HVAC ranked
- 10
- Average rating
- 4.9★
- Reviews analyzed
- 6,720
- Area codes
- 636, 314
Stay Cool Climate Control
⭐ 5.0 · 1144 reviews
407 Sonderen St, O'Fallon, MO 63366
Design Aire Heating and Cooling
⭐ 5.0 · 877 reviews
103 Church St #20, O'Fallon, MO 63366
Hoff Heating & AC
⭐ 4.9 · 1519 reviews
1520 Kemmar Ct, O'Fallon, MO 63366
Swiss Air Heating & Cooling
⭐ 4.9 · 937 reviews
406 E Wabash St, O'Fallon, MO 63366
Faszold Heating and Cooling
⭐ 4.9 · 870 reviews
1613 E Terra Ln, O'Fallon, MO 63366
Hosack Plumbing, Heating & Cooling
⭐ 4.9 · 725 reviews
110 W Pitman St, O'Fallon, MO 63366
KirbnJays Heating & Cooling
⭐ 4.9 · 366 reviews
674 Whispering Willow Dr, O'Fallon, MO 63366
One Hour Heating & Air Conditioning of O'Fallon
⭐ 5.0 · 48 reviews
113 Triad Center W, O'Fallon, MO 63366
Johnstone Supply
⭐ 4.8 · 140 reviews
3120 Industrial Park Pl W Dr, St Peters, MO 63376