| Employer | State | City | |
| S. P. McCarl & Company, Inc. | Pennsylvania | Altoona | View Profile |
| Sarracco Mechanical Services Inc. | Connecticut | Naugatuck | View Profile |
| Schischek, Inc | Virginia | Chantilly | View Profile |
| SEMCO, Incorporated | Missouri | Columbia | View Profile |
| Service Logic | Colorado | Denver | View Profile |
| Service Solutions Group | Arizona | Phoenix | View Profile |
| Service Solutions Group | Arizona | Phoenix | View Profile |
| Service Solutions Group | Arizona | Phoenix | View Profile |
| Shapiro & Duncan, Inc. | Maryland | Rockville | View Profile |
| ShureLine Construction & ShureLine Electrical | Delaware | Smyrna | View Profile |
| ShureLine Construction & ShureLine Electrical | Delaware | Smyrna | View Profile |
| SITECH Inc. | Florida | Plant City | View Profile |
| Skill Supply | New Mexico | Albequerque | View Profile |
| Smart Air Systems, Inc. | Florida | Margate | View Profile |
| Spears Refrigeration | Texas | Arlington | View Profile |
| Stanco Climate Control | New Jersey | Manalapan | View Profile |
| Standard Heating & Air Cond. Co. | Alabama | Birmingham | View Profile |
| Standard Mechanical Systems | Texas | Houston | View Profile |
| Standard Renewable Energy | Texas | Houston | View Profile |
| Standard Renewable Energy | Texas | Houston | View Profile |
| Stantec | New York | New York | View Profile |
| Stantec | New York | New York | View Profile |
| Stantec | New York | New York | View Profile |
| Star Service, Inc. of Jackson | Mississippi | Byram | View Profile |
| Stiles Heating and Cooling | Georgia | Bogart | View Profile |
| Stulz Air Technology Systems, Inc. | Maryland | Frederick | View Profile |
| Sun Kool Air Conditioning Inc | Florida | Ocala | View Profile |
| SystemAire, Inc. | Missouri | Earth City | View Profile |