| 10-20 Services | C20 + C10 | 2015 | Active |
| A C J C Air Conditioning | C20 | 2022 | Active |
| AC All Star | C20 | 2014 | Active |
| Acc & Engineering LLC | C20 + A, B, C10 +1 | 2021 | Active |
| Advanced Improvements Inc | C20 + B, C10, C36 +1 | 2010 | Active |
| Affinity Refrigeration And HVAC Inc. | C20, C38 | 2014 | Active |
| Air Concepts | C20 + B, C36 | 1988 | Active |
| Air Flow Control Air JV | C20, C38 + A, B, C2 +2 | 2019 | Active |
| Air Flow Mechanical Inc | C20 | 1977 | Active |
| Air Max JB Mechanical Heating And Cooling | C20 | 2022 | Active |
| Airkon Heating & Cooling | C20 | 2021 | Active |
| Albert Air Inc | C20 | 1991 | Active |
| Allegiance 76 Heating And Air Conditioning LLC | C20 | 2026 | Active |
| Alpha Energy Group Inc | C20 + B, C10, C36 | 2010 | Renew by Dec 31, 2026 |
| Alpha Enviro Tech Inc | C20 + B, C39 | 2017 | Active |
| Alps Air Conditioning & Heating Inc | C20 | 1993 | Active |
| American Air Balance Co LLC | C20 + D62 | 1989 | Active |
| Amko Contractors Inc | C20 + B | 2018 | Active |
| Anaheim Refrigeration Inc | C20, C38 | 1989 | Active |
| Aria's Air Conditioning Inc | C20 | 2023 | Active |
| Associated Heating & Air Inc | C20 | 1990 | Renew by Dec 31, 2026 |
| Blake Air Conditioning & Service Co Inc | C20 | 1980 | Active |
| Boiler Dynamics Inc | C4 | 2016 | Active |
| Building Air Systems | C20 + C10 | 2017 | Active |
| Caliber Heating & Air Conditioning Inc | C20 | 2005 | Active |
| Climate Air Masters Inc | C20 | 1994 | Active |
| Comfort Guards Heating And Air Conditioning LLC | C20 | 2026 | Active |
| Conquest Air Inc | C20 | 2002 | Active |
| Continental Design Build Inc | C20 + B, HAZ | 1971 | Active |
| Control Air Enterprises LLC | C4, C20, C38 + B, C2, C10 +1 | 2019 | Active |
| Cool Air Refrigeration | C20, C38 | 2012 | Active |
| Coolets Heating And Airconditioning Inc | C20 + C10 | 2024 | Active |
| Coolpros Heating And Air | C20 | 2024 | Active |
| Cooper Andrew D Company | C20 + B, C36 | 1963 | Active |
| Creative Air Mechanical Services LLC | C20 | 2014 | Active |
| D B Sales & Service | C4, C20 | 2013 | Active |
| Delta T H V A C Inc | C20 | 2016 | Active |
| Diversified Thermal Services LLC | C20, C38 + B, C10 | 1991 | Active |
| Earth & Sun Construction Inc | C20 + B, C33, C36 | 2020 | Active |
| Eco Home Solutions | C20 + B, C36 | 2014 | Active |
| Ecotech Refrigeration & H V A C Inc | C20, C38 | 2013 | Active |
| Electrician Services Corp | C20 + B, C10 | 2005 | Active |
| Falcon Airflow LLC | C20 | 2025 | Active |
| Famous Amos HVAC Inc | C20 | 2017 | Active |
| Fitzgerald Plumbing Service Company | C20 + C36 | 2024 | Renew by Nov 30, 2026 |
| Fitzhauer Construction Inc | C20 + B, C10, C39 | 2015 | Active |
| Four Seasons Heating And Air LLC | C20 | 2025 | Active |
| Guaranteed Air Inc | C20 | 2014 | Active |
| H & V Heating Air Conditioning And Refrigeration | C20 | 2011 | Active |
| Home Comfort USA Heating & Cooling | C20 + C2, C10, C36 | 2023 | Active |
| Horizon Heating & Air Conditioning Inc | C20 | 1992 | Active |
| How Much ? Air | C20 | 2021 | Active |
| Hughes Mechanical Inc | C20 | 2022 | Active |
| HVAC Forme LLC | C20 | 2021 | Active |
| HVAC Install Pros | C20 + B | 2010 | Active |
| HVAC Lux-Air | C20 | 2025 | Active |
| Incomparable Heating & Air Inc | C20 | 2023 | Active |
| Irvine Valley Air Conditioning Inc | C20 + A, C36 | 1992 | Active |
| J D F Construction Inc | C20 + ASB, B, C10 +3 | 2011 | Active |
| JC Heating & Air Conditioning Systems Inc | C20 | 2019 | Active |
| JV Heating And Air | C20 | 2016 | Active |
| K B E C Inc | C20 + B | 2015 | Active |
| K-Tech Mechanical Inc | C38 | 2005 | Active |
| Kahuna Comfort Plumbing Heating & Air | C20 + C36, C42 | 2018 | Active |
| Leal Pro - Mechanical H V A C Inc | C20 | 2019 | Active |
| Local Air Conditioning Company | C20 | 2003 | Active |
| M3 Mechanical | C20 | 2000 | Active |
| Madison Air Inc | C20 | 1997 | Active |
| Magna Plumbing | C20 + C36 | 1991 | Active |
| Martin J Indoor Air Quality LLC | C20 | 2014 | Renew by Dec 31, 2026 |
| MG Developer's Inc | C20 + B, C36 | 2012 | Active |
| Mission Sheet Metal Inc | C20 + C43 | 1979 | Active |
| Mtac Heating & Air Inc | C20 | 2025 | Active |
| N K S Mechanical Contracting Inc | C20 + B | 2005 | Active |
| N S W C Mechanical Service LLC | C20, C38 + C10, C36 | 2017 | Active |
| Nicholas Mechanical HVAC Inc | C20 | 2014 | Active |
| Performance Air Systems | C20 | 1998 | Active |
| Peter's Heating & Air Conditioning | C20 | 2019 | Active |
| Petra Air System Inc | C20 | 2012 | Active |
| PMS Heating & Cooling LLC | C20 | 2025 | Active |
| Precise HVAC Services Inc | C20 | 2011 | Active |
| Precision Air Balancing Company | C20 + D62 | 1991 | Active |
| Prime Enc Inc | C20 + B, C36, C39 +1 | 2014 | Active |
| Pro Home Improvement And Repair Corp | C20 + B | 2016 | Active |
| Pro Quality Plumbing Heating & Air | C20 + B, C36 | 1991 | Active |
| Pro Star Mechanical Services | C4, C20 + B | 2009 | Active |
| Pulse Heating And Air Corp | C20 + A, B, C10 +1 | 2025 | Active |
| Quality Air Industries Inc | C20 | 2019 | Active |
| RJ Air Conditioning Services Inc | C20 | 2014 | Active |
| RK Air Inc | C20 | 2015 | Active |
| Rosales Aire Inc | C20 | 2021 | Active |
| Sano Plumbing Heating AC | C20 + C36 | 2021 | Active |
| Select Home Improvements Inc | C20 + B | 2018 | Active |
| Shark HVAC Inc | C20 | 2026 | Active |
| So Cool Air Conditioning And Heating Incorporated | C20 | 1996 | Active |
| South Coast Facility Services | C4, C20 + B, C10, C36 | 2005 | Active |
| South St Investments LLC | C20, C38 + B, C10, D62 | 1984 | Active |
| Subtech HVAC | C20 | 2023 | Active |
| Systems X T Inc | C20, C38 + B, C10 | 2004 | Active |
| Temp O HVAC Corp | C20 | 2025 | Active |