| Bahnson, Inc. | Clemmons | NC | $0 |
| Bailey Ventures LLC | Vidor | TX | $0 |
| Baker Services Inc. | Glenshaw | PA | $0 |
| Ballard Contracting Solutions LLC | Clinton Township | MI | $0 |
| Barberio Enterprises, Inc. | Shadow Hills | CA | $0 |
| Bar-b Plumbing Company, Incorporated | Copperas Cove | TX | Subcontractor |
| Bar J Plumbing LLC | Socorro | NM | $0 |
| Barnes & Dodge Inc. | Lenexa | KS | Subcontractor |
| Barnett Plumbing Inc. | Laurel | MD | $0 |
| Barrack-nickols Contracting, Inc. | Santee | CA | Subcontractor |
| Barry Associates, Inc. | Preston | CT | $0 |
| Barwick Plumbing Co. LLC | Pinewood | SC | $0 |
| Base, Inc. | San Juan | PR | $0 |
| Base Mechanical, Inc. | Waterford | CT | Subcontractor |
| Bassett Inc. | Kaukauna | WI | Subcontractor |
| Batjer Service, LLC | Abilene | TX | $0 |
| Baton Rouge Sewer & Drain Service Inc. | Baton Rouge | LA | $0 |
| Bay Cities Fire Protection, Inc. | Santa Rosa | CA | $0 |
| Bayou Mechanical, Inc. | Crestview | FL | Subcontractor |
| Bay To Bay Balancing, Inc. | Lutz | FL | Subcontractor |
| Bc Mechanical, LLC | Redmond | OR | $0 |
| Beacon Air Conditioning, Heating And Refrigeration, Inc. | Kenner | LA | $0 |
| Beckley Mechanical Company | Fairbanks | AK | Subcontractor |
| Beck's Plumbing, Inc. | Justin | TX | $0 |
| Bel-aire Mechanical, LLC | Phoenix | AZ | Subcontractor |
| Bell Bci Company, LLC | Rochester | NY | $0 |
| Bell Constructors, LLC | Rochester | NY | Subcontractor |
| Bell Products, Inc. | Napa | CA | Subcontractor |
| Bendler Mechanical Co. Inc. | High Ridge | MO | $0 |
| Benkari LLC | Detroit | MI | $0 |
| Best Commercial Energy Services Inc. | Akron | OH | $0 |
| Best Sewer & Drain Service, Inc. | Kenner | LA | $0 |
| Beverly Hills Mechanical Services Inc. | Finksburg | MD | Subcontractor |
| B & F Mechanical LLC | Walterboro | SC | $0 |
| B & G Refrigeration Company, Inc. | Jacksonville | FL | $0 |
| B & H Mechanical, Inc. | Las Cruces | NM | Subcontractor |
| Billy Pape Plumbing Inc. | Raymond | MS | $0 |
| Bishop Heating & Air Conditioning, Incorporated | Bishop | CA | $0 |
| Bismarck Heating & Air Conditioning, Inc. | Bismarck | ND | $0 |
| B & J Refrigeration, Inc. | Tucson | AZ | $0 |
| B. K. Mechanical Services, Inc. | Silsbee | TX | $0 |
| Blair Fire Protection, LLC | Butler | WI | $0 |
| Blanchard Mechanical Contractors Inc. | Amite | LA | $0 |
| Blaschke Umwelttechnik GMBH | Meitingen | | $0 |
| Blaylock Heating & Air Conditioning Inc. | Fort Smith | AR | Subcontractor |
| Blythe Mechanical Inc. | Bellingham | WA | Subcontractor |
| BMWC Constructors Inc. | Tualatin | OR | $0 |
| Boilermatic Welding Industries, Inc. | Medford | NY | $0 |
| Boiler, Pressure Vessels Inspection Agency, Inc. | Bel Air | MD | $0 |
| Bombard Mechanical LLC | Las Vegas | NV | Subcontractor |
| Bonded Filter Co. LLC | Nashville | TN | Subcontractor |
| Booth Plumbing Co. Inc. | Columbus | GA | Subcontractor |
| Borte Mechanical Services LLC | Moyock | NC | Subcontractor |
| Boston Mechanical Services LLC | Devens | MA | Subcontractor |
| Botone Industries, LLC | Albuquerque | NM | $0 |
| Bracken Plumbing Inc. | Schertz | TX | Subcontractor |
| Bradley General Building Inc. | Helendale | CA | Subcontractor |
| Brady Parts Inc. | Greensboro | NC | $0 |
| Brady Sales And Service, Inc. | Greensboro | NC | Subcontractor |
| Brady Services, Inc. | Greensboro | NC | $0 |
| Brazosport Plumbing & Heating Co. | Angleton | TX | $0 |
| B & R Contractors Inc. | Pasadena | MD | $0 |
| Breathitt Mechanical Company, Inc. | Jackson | KY | $0 |
| Brian Trematore Plumbing & Heating, Inc. | Fairfield | NJ | Subcontractor |
| Bridger's Hvac And Welding, LLC | Milan | TN | $0 |
| Brio Construction LLC | Miami Beach | FL | Subcontractor |
| Brothers Electro Mechanical Inc. | Albuquerque | NM | $0 |
| Brutinel Plumbing & Electrical Inc. | Casa Grande | AZ | $0 |
| Buford Plumbing Company Inc. | Jackson | MS | Subcontractor |
| Built Environmental Systems Testing, LLC | Shawnee | OK | Subcontractor |
| Bullet Proof Mechanical Service, Inc. | Willmar | MN | Subcontractor |
| Burton Construction Inc. | Meridian | MS | $0 |
| Butler Balancing Co. Inc. | Downingtown | PA | Subcontractor |
| Butters-fetting Co. Inc. | Milwaukee | WI | Subcontractor |
| B & V Mechanical Inc. | Grand Rapids | MI | $0 |
| Byrd Industrial Services, Inc. | Kernersville | NC | $0 |
| Byrnes Mechanical Contractors, Inc. | West Monroe | LA | Subcontractor |
| Cabana Mechanical Inc. | San Antonio | TX | Subcontractor |
| Cal-bay Service, Inc. | Benicia | CA | $0 |
| Calcasieu Mechanical Contractors, Inc. | Lake Charles | LA | Subcontractor |
| California Boiler Works, Inc. | Clayton | CA | Subcontractor |
| California United Mechanical, Inc. | San Jose | CA | Subcontractor |
| Calvert Plumbing And Heating Company, Inc. | Towson | MD | $0 |
| Campbell Plumbing Contractors Southeast, Inc. | Jacksonville | FL | Subcontractor |
| Capital City Mechanical Services, LLC | Peachtree Corners | GA | $0 |
| Capital Heating & Cooling, Inc. | Lacey | WA | Subcontractor |
| Capital Technologies Inc. | Mckeesport | PA | $0 |
| Capitol Contractors, Inc. | Fredericksburg | VA | Subcontractor |
| Capitol Mechanical Contractors, Inc. | Capitol Heights | MD | Subcontractor |
| Captain Frost LLC | San Diego | CA | Subcontractor |
| Carlito B. Pamintuan | Yigo | GU | Subcontractor |
| Carllo, Inc. | Enfield | CT | Subcontractor |
| Carolina Pipe Cleaning Inc. | Rockwell | NC | $0 |
| Carolina Precision Cooling LLC | Clayton | NC | Subcontractor |
| Carwile Mechanical Contractors, Inc. | Cookeville | TN | $0 |
| Cascade Comfort Service, Inc. | Anderson | CA | Subcontractor |
| Cascade Heating And Specialties, Inc. | Bend | OR | $0 |
| Cason's Water Conditioning, Inc. | Palm Harbor | FL | $0 |
| Cassell Brothers Heating And Cooling, LLC | Irmo | SC | $0 |
| Cayce Co. Inc. | Florence | SC | Subcontractor |
