| Shadow Mountain Heating & Air LLC | C-21B | Active |
| Siemens Industry Inc | C-21D | Active |
| Sierra Air Conditioning & Plumbing | C-21 | Active |
| Sierra Air Conditioning Inc | C-21 | Active |
| Sierra Nevada Home Services LLC | C-21B | Active |
| Silver Hill Heating & Air Conditioning LLC | C-21B | Active |
| Silver State Commercial Refrigeration LLC | C-21 | Active |
| Silver State Refrigeration & HVAC LLC | C-21 | Active |
| Silverado Mechanical LLC | C-21 | Active |
| Silverline HVAC | C-21 | Active |
| Simple Mechanical LLC | C-21 | Active |
| Simply Cooling Heating Plumbing | C-21B | Active |
| Sin City Air Conditioning LLC | C-21 | Renew by Dec 31, 2026 |
| Sin City R E Heating & Cooling LLC | C-21B | Active |
| Singapore HVAC LLC | C-21B | Active |
| Sky Air & Heat LLC | C-21B | Active |
| Smart Air Heating & Cooling | C-21 | Active |
| Snow Frosty Heating & Air Conditioning Inc | C-21B | Active |
| So Cool AC Heating & Refrigeration LLC | C-21 | Active |
| Southern Nevada Air Conditioning And Heating | C-21 | Active |
| Southland Industries | C-21 | Active |
| Southwest Mechanical Inc | C-21 | Active |
| Space Heating And Cooling LLC | C-21B | Active |
| Spartan Air Conditioning & Refrigeration LLC | C-21 | Active |
| Spartan Mechanical Services Inc | C-21 | Active |
| Spot On Air Conditioning And Heating | C-21 | Active |
| Stainless Steel Fabrication Inc | C-21 | Active |
| Standard Air LLC | C-21B | Active |
| Stay Kool LLC | C-21 | Active |
| Stellar HVAC R Service LLC | C-21B | Active |
| Step By Step Heating And Air Conditioning LLC | C-21B | Active |
| Sun Valley Air LLC | C-21B | Active |
| Sunbelt Controls Inc | C-21 | Active |
| Sunwarriors Air Conditioning & Heating LLC | C-21 | Active |
| Super Service Cooling, Heating & Plumbing | C-21B | Active |
| Support Mechanical Services | C-21 | Active |
| Support Refrigeration Inc | C-21 | Active |
| Supreme Air Conditioning And Heating LLC | C-21B | Active |
| T & G Mechanical LLC | C-21 | Active |
| T & V Air Conditioning LLC | C-21 | Active |
| T S Mechanical | C-21 | Active |
| Tanana Air Conditioning & Heating | C-21 | Active |
| Tech Field Solutions LLC | C-21A, C-21B | Active |
| Techcool Cooling & Heating LLC | C-21 | Active |
| Technoclima LLC | C-21B | Active |
| Tempbusters LLC | C-21B | Active |
| Temperature Source LLC | C-21 | Active |
| Tempercare Heating & Cooling | C-21B | Active |
| The A C Company NV LLC | C-21B | Active |
| The Cooling Company | C-21 | Active |
| The Future Of Heating And Cooling LLC | C-21B | Active |
| The Heating & Cooling Company LLC | C-21B | Active |
| The Honest Plumber | C-21 | Active |
| The Professional Installer Maintenance & Service LLC | C-21 | Active |
| The Right Guys HVAC & Plumbing | C-21B | Active |
| Thermal Boilers & Controls LLC | C-1A | Active |
| Thermo-Dynamix LLC | C-21 | Active |
| Titan Air Conditioning & Heating LLC | C-21 | Active |
| TJ Air Conditioning, Heating And Refrigeration | C-21A, C-21B | Active |
| Tom The A C Guy LLC | C-21B | Active |
| Top Tech Air Conditioning And Heating Services LLC | C-21 | Active |
| Top Tier Services LLC | C-21 | Active |
| Trails End Mobile Home Serv Inc | C-21B | Active |
| Treasure Island LLC | C-21 | Active |
| Trex Cooling Tower Inc | C-21 | Active |
| Tri City Air Conditioning LLC | C-21 | Active |
| Triple Seven HVAC LLC | C-21B | Active |
| Tru Air LTD | C-21B | Active |
| Trujillos Refrigeration Inc | C-21 | Active |
| Truth Cooling And Heating LLC | C-21B | Active |
| U S Master Services LLC | C-21B | Active |
| Ultra Heating & Cooling & Refrigeration | C-21 | Active |
| United Air Conditioning And Heating LLC | C-21 | Active |
| United SS Fabricators Inc | C-21 | Active |
| Upwind LLC | C-21 | Active |
| Urban Heating & Air LLC | C-21 | Active |
| Urban Mechanical Service | C-21 | Active |
| Urbn Air LLC | C-21B | Active |
| Urgent Air And Plumbing | C-21 | Active |
| USA Air Conditioning Inc | C-21 | Active |
| Valley Air Conditioning & Refrigeration Inc | C-21 | Active |
| Vander Heating And Cooling LLC | C-21B | Active |
| Vargach AC & Heating LLC | C-21B | Active |
| Vegas Air Pro LLC | C-21B | Active |
| Vegas Heat LLC | C-21 | Renew by Dec 31, 2026 |
| Vegas HVAC Solutions LLC | C-21B | Active |
| Vegas Knight & Day Heating And Cooling LLC | C-21B | Active |
| Vegas Valley Heating & Cooling LLC | C-21 | Active |
| Villanueva Services Inc | C-21B | Active |
| Wann Mechanical | C-21 | Active |
| Washington Refrigeration LTD | C-21B | Active |
| Wave Heating & Cooling LLC | C-21B | Active |
| We Care Air LLC | C-21B, C-21D | Active |
| We Fix Em LLC | C-21B | Active |
| Weather One Heating & Cooling | C-21 | Active |
| Western Commercial Services LLC | C-21 | Active |
| Wild West Heating & Cooling LLC | C-21B | Active |
| Xcellence Cooling & Heating LLC | C-21 | Active |
| Yaya Heating & Air Conditioning LLC | C-21B | Active |
| Yes! Air Conditioning, Heating, Plumbing And Electric | C-21 | Active |