| Haakon - Custom Air Handling Units | Trane Company, The |
| Hayes/Shay by Airfan | Haldeman, Inc. |
| Heat Exchangers - APV, Wheatley | Weil Aquatronics, Inc. |
| Heat Exchangers - Plate & Frame; Polaris | K.H. Watts Company, Inc. |
| Heat Exchangers, Air-to-Air (Des-Champs Labs) | Air Conditioning Specialties Co. |
| Heat Pipes (Des-Champs Labs) | Air Conditioning Specialties Co. |
| Heat Recovery | DB Sales & Service |
| Heatcraft Coils | JD Sales Co., Inc. |
| Heaters, Electric (Berko) | Air Conditioning Specialties Co. |
| Heaters, Electric Duct (Brasch & Enviro-Tec) | Air Conditioning Specialties Co. |
| Heating Equipment | Haldeman, Inc. |
| Heating Equipment, Gas-fired (ICE) | Air Treatment Corp. |
| Heating Equipment, Gas-fired (Modine, Industrial Airsystems) | Air Conditioning Specialties Co. |
| Heating Panels, Electric Radiant (Aztec) | Air Conditioning Specialties Co. |
| Heating Products | Trane Company, The |
| Heatway - Radiant Floors/Snowmelting | Dawson Co. |
| Holzrubber Co., Inc. | Sausse M.W., & Co., Inc. |
| Hot Water Heaters | DB Sales & Service |
| Humidifiers, Duct & Room (Dri-Steem) | Air Conditioning Specialties Co. |
| Humidifiers, Electronic (Carnes) | Air Treament Corp. |
| Humidifiers, Industrial (Bahnson) | Air Conditioning Specialties Co. |
| Humidifiers, Steam - Neptronics | K. H. Watts Company, Inc. |
| HVAC Duct Cleaning | escorp - HVAC Duct Cleaning |
| HVAC System Decontamination | Wescorp - HVAC Duct Cleaning |
| HVAC System Inspection, Diagnosis, Reporting | Wescorp - HVAC Duct Cleaning |
| Hydronic | American Air Balance Co., Inc. |
| Hydronic Accessories - Wheatley | Weil Aquatronics |
| Hydronics by Sterling | Haldeman, Inc. |
| Hydronic Specialties | Paco Pumps |