| RLM Mech LLC | Warminster | PA | $0 |
| RLRGP Inc. | Johnstown | PA | Subcontractor |
| R Mcglynn Plumbing Corp. | Staten Island | NY | $0 |
| Rm Chris Sheet Metal Inc. | West Jordan | UT | Subcontractor |
| Robbie To The Rescue Plumbing Services, LLC | Paris | TN | $0 |
| Robbins Air Inc. | Aberdeen | WA | $0 |
| Robert D. Rieser, Inc. | Langhorne | PA | $0 |
| Robert M. Morgan | Colstrip | MT | $0 |
| Robinson And Son Plumbing And Heating, Inc. | Scott Depot | WV | $0 |
| Robinson Heating And Air Conditioning Inc. | Middletown | OH | Subcontractor |
| Rock Enterprises Construction, LLC | Kenner | LA | $0 |
| Rocky Mountain Mechanical Inc. | Emmett | ID | $0 |
| Ronco Mechanical Contractors, Inc. | Clinton | MD | Subcontractor |
| Roseberrys' Plumbing And Heating, Inc. | Durango | CO | $0 |
| Roth-zachry Heating, Inc. | Aurora | OR | $0 |
| Rov Enterprises, Inc. | Mcclellan | CA | $0 |
| RPM Mechanical LLC | Castroville | TX | Subcontractor |
| R&R Heating & Air Conditioning, Inc. | Spokane | WA | Subcontractor |
| Rsanalysis, LLC | El Dorado Hills | CA | Subcontractor |
| RSQ Fire Protection, LLC | Indianapolis | IN | Subcontractor |
| RTS Water Solutions LLC | Gambrills | MD | Subcontractor |
| Ruotolo Mechanical, Inc. | New Haven | CT | $0 |
| Rupert Plumbing & Heating Co. Inc. | Albuquerque | NM | Subcontractor |
| Rushco Energy Specialists, Inc. | Hurst | TX | $0 |
| Russell F Geiger | Newbury Park | CA | Subcontractor |
| R. W. Warner, Inc. | Frederick | MD | Subcontractor |
| Rx Plumbing, LLC | Murrieta | CA | Subcontractor |
| Ryan Fireprotection Inc. | Noblesville | IN | Subcontractor |
| Ryan Mechanical Inc. | Las Vegas | NV | Subcontractor |
| Ryan Plumbing, Heating, Air Conditioning And Fire Protection LLC | Rochester | NY | $0 |
| S2 Industrial Inc. | Marcola | OR | Subcontractor |
| Safe Aire Heating And Cooling Company, Inc. | Albany | GA | Subcontractor |
| Safeguard Corporation | Sylacauga | AL | Subcontractor |
| Sagamore Plumbing & Heating LLC | Hingham | MA | Subcontractor |
| Sage Mechanical LLC | Anchorage | AK | $0 |
| Samco, Inc. | Topeka | KS | $0 |
| Sams Air Conditioning Maintenance Service, Inc. | Alexandria | LA | $0 |
| Samster Co. LLC | Germantown | WI | $0 |
| Sanford & Burtis Fire Equipment, Inc. | Fulton | NY | $0 |
| Sanford Water Works & Lanscaping Inc. | Uvalde | TX | $0 |
| Sankei Co. Ltd. | Fukuoka | | Subcontractor |
| Santapaul Corp. | Philadelphia | PA | $0 |
| Sauer Group, LLC | Columbus | OH | Subcontractor |
| Sauer Mechanical LLC | Jacksonville | FL | Subcontractor |
| Schlosser & Associates Mechanical Contractors, Inc. | Newark | DE | $0 |
| Schmitt Refrigeration Air Conditioning & Heating Inc. | Evansville | IN | $0 |
| Schorr GMBH, Heizungs-, Luftungs- Und Sanitar-technik | Sembach | | $0 |
| Scottco Mechanical Contractors, Inc. | Amarillo | TX | $0 |
| Scott Systems, Inc. | Pine Bluff | AR | $0 |
| Scranton Sheet Metal Inc. | Scranton | PA | Subcontractor |
| S&d/osterfeld Mechanical Contractors, Inc. | Dayton | OH | $0 |
| Seismic Control Installations, Inc. | Hillsborough | NC | Subcontractor |
| Seneca Mechanical LLC | Nolanville | TX | Subcontractor |
| Sentry Mechanical, LLC | Pittsburgh | PA | Subcontractor |
| Sepideh Inc. | Kapolei | HI | $0 |
| Service Works LLC | Springfield | VA | Subcontractor |
| Severson Companies, Inc. | Albany | OR | $0 |
| Shannons Inc. | International Falls | MN | $0 |
| Sharpe Heating & Air Inc. | Vicksburg | MS | $0 |
| Sheet Metal Inc. | Anchorage | AK | Subcontractor |
| Sheet Metal Specialties, Inc. | Casper | WY | $0 |
| Shinn Mechanical Inc. | Kent | WA | $0 |
| Shore Test And Balance, LLC | Denton | MD | Subcontractor |
| Sigari Corp. | Ponce | PR | $0 |
| Signet Controls, Inc. | Westlake Village | CA | Subcontractor |
| S.i. Goldman Company, Inc. | Longwood | FL | $0 |
| Silverdale Plumbing & Heating, Inc. | Silverdale | WA | Subcontractor |
| Silver Sheet Metal, Inc. | Augusta | GA | $0 |
| Simco Mechanical Inc. | Altadena | CA | Subcontractor |
| Simmons Heating.cooling.electrical. Inc. | Laurinburg | NC | $0 |
| S K Mechanical LLC | Manchester | CT | $0 |
| S & L Mechanical, Inc. | Leesport | PA | $0 |
| SMC Inc. | Terre Haute | IN | $0 |
| Smedley & Associates Plumbing & Heating, Inc. | Layton | UT | $0 |
| Smith Refrigeration, Inc. | Panama City | FL | $0 |
| Smith Service Corporation | Decatur | AL | $0 |
| Smiths Inc. Of Dothan | Dothan | AL | Subcontractor |
| Sne Building Systems, Inc. | East Granby | CT | Subcontractor |
| S & O Construction Services, Inc. | Pleasant Valley | NY | $0 |
| So Contracting Inc. | Radcliff | KY | Subcontractor |
| Sojam LLC | Annapolis Junction | MD | Subcontractor |
| South Bay Heating & Air Conditioning Inc. | Long Beach | CA | $0 |
| South Central Heating & Plumbing Co. Inc. | Jackson | MS | Subcontractor |
| Southern Air, L.L.C. | Pineville | LA | $0 |
| Southern Fire Protection Of Orlando Inc. | Sanford | FL | Subcontractor |
| Southern Heating & Cooling Inc. | Scottsboro | AL | Subcontractor |
| Southern Mechanical, LLC | West Warwick | RI | Subcontractor |
| Southglobal Corporation | San Fernando | PAMPANGA | Subcontractor |
| Southwest Air Systems Inc. | Alamogordo | NM | Subcontractor |
| Southwest Mechanical Services Inc. | El Cajon | CA | Subcontractor |
| Spangler & Boyer Mechanical Inc. | York | PA | $0 |
| SPC Mechanical Corporation | Wendell | NC | Subcontractor |
| Spears Services, Inc. | Johnson City | TN | Subcontractor |
| Specialty Fitters, Inc. | Elyria | OH | $0 |
| Specialty Mechanical Services LLC | Everett | WA | $0 |
| Specialty Testing Service Co. | Raleigh | NC | Subcontractor |
| Sphere Mechanical Corp. | Escondido | CA | Subcontractor |
| Spreen Refrigeration Inc. | Edinburg | TX | $0 |
| Sprick Gerald R | Bay City | WI | $0 |
| Springfield Engineering Co. | Springfield | MO | $0 |
