| # | Organization | Country | Specialty | Web Address |
|---|
| 11 | Air-Conditioning & Refrigeration Institute (ARI) | USA | Manufacturer | Click here. |
| 12 | American Backflow Prevention Association | USA | Construction, Facility, Water | Click here. |
| 13 | American Boiler Manufacturer's Association (ABMA) | USA | Boiler | Click here. |
| 14 | American Council of Engineering Companies (ACEC) | USA | Professional | Click here. |
| 15 | American Gas Association (AGA) | USA | Fuel, Professional | Click here. |
| 16 | American Home Inspector Directory | USA | Construction, Consulting Engineering, Contractor, Environmental, Indoor Air Quality, Instrumentation & Control, Insulation, Residential, Water | Click here. |
| 17 | American National Standards Institute (ANSI) | USA | Standards & Codes | Click here. |
| 18 | American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) | USA | Professional | Click here. |
| 19 | American Society of Mechanical Engineers (ASME) | International | Professional, Standards & Codes | Click here. |
| 20 | Associated Air Balance Council (AABC) | USA | Air Conditioning & Refrigeration, Professional | Click here. |
