| Fire protection | ||
| Rank | Company/Location | $Millions |
| 29 | S.A. Comunale Co. Inc., Barberton, Ohio | $100.46 |
| 42 | VSC/Virginia Sprinkler Corp., Ashland, Va. | $91.10 |
| 23 | J.F. Ahern Co., Fond du Lac, Wis. | $65.17 |
| 1 | EMCOR Group Inc., Norwalk, Conn. | $55.44 |
| 73 | Great Lakes Plumbing & Heating Co., Chicago | $20.64 |
| 67 | Grunau Co. Inc., Oak Creek, Wis. | $17.34 |
| 24 | John E. Green Co., Highland Park, Mich. | $15.80 |
| 114 | Triad Mechanical Inc., Portland, Ore. | $7.37 |
| 106 | Farmer & Irwin Corp., Riviera Beach, Fla. | $2.82 |
| 100 | Stewart Mechanical Enterprises Inc., Louisville, Ky. | $0.73 |
| Refrigeration | ||
| Rank | Company/Location | $Millions |
| 1 | EMCOR Group Inc., Norwalk, Conn. | $110.88 |
| 64 | MacDonald-Miller Facility Solutions | $14.41 |
| 34 | John W. Danforth Co., Buffalo, N.Y. | $10.36 |
| 28 | McKinstry Co., Seattle | $9.52 |
| 26 | Hill Mechanical Group, Chicago | $6.20 |
| 60 | Joule Industrial Contractors, Philadelphia | $5.96 |
| 6 | Limbach Facility Services, Pittsburgh | $4.49 |
| 46 | Lee Co., Franklin, Tenn. | $4.36 |
| 22 | Murphy Co. Mechanical Contractors and Engineers, St. Louis | $3.27 |
| 96 | Lawson Mechanical Contractors, Sacramento, Calif. | $2.01 |
| Water/Wastewater treatment | ||
| Rank | Company/Location | $Millions |
| 1 | EMCOR Group Inc., Norwalk, Conn. | $129.36 |
| 3 | American Residential Services/AMS/ Rescue Rooter, Downers Grove, Ill. | $69.05 |
| 62 | James McCullagh Co. Inc., Plainview, N.Y. | $64.68 |
| 91 | Monterey Mechanical Co., Oakland, Calif. | $37.27 |
| 14 | John J. Kirlin Inc., Rockville, Md. | $33.45 |
| 23 | J.F. Ahern Co., Fond du Lac, Wis. | $23.84 |
| 30 | Harris Companies, St. Paul, Minn. | $23.04 |
| 34 | John W. Danforth Co., Buffalo, N.Y. | $20.72 |
| 18 | MMC Corp., Leawood, Kan. | $18.59 |
| 76 | Durr Mechanical Construction Inc., New York | $17.46 |
| Controls/TAB | ||
| Rank | Company/Location | $Millions |
| 7 | FirstEnergy Facilities Services Group, Akron, Ohio | $79.60 |
| 54 | MMR Group, Baton Rouge, La. | $72.00 |
| 9 | Residential Services Group, Dayton, Ohio | $70.00 |
| 2 | Comfort Systems USA Inc., Houston | $57.37 |
| 11 | ACCO Engineered Systems Inc., Glendale, Calif. | $31.50 |
| 6 | Limbach Facility Services, Pittsburgh | $22.44 |
| 14 | John J. Kirlin Inc., Rockville, Md. | $22.30 |
| 15 | KeySpan Energy Services, Brooklyn, N.Y. | $19.39 |
| 20 | Therma Inc., San Jose, Calif. | $17.94 |
| 52 | P1 Group, Lenexa, Kan. | $16.00 |
| HVAC | ||
| Rank | Company/Location | $Millions |
| 1 | EMCOR Group Inc., Norwalk, Conn. | $646.80 |
| 4 | Lennox Retail/Service Experts, Richardson, Texas | $611.70 |
| 2 | Comfort Systems USA Inc., Houston | $606.47 |
| 3 | American Residential Services/AMS/Rescue Rooter, Downers Grove, Ill. | $310.73 |
| 19 | Cal-Air Inc., Whittier, Calif. | $180.00 |
| 6 | Limbach Facility Services, Pittsburgh | $179.52 |
| 21 | Chas Roberts Air Conditioning Inc., Phoenix | $172.80 |
| 11 | ACCO Engineered Systems Inc., Glendale, Calif. | $157.50 |
| 17 | Beutler Corp., McClellan Park, Calif. | $145.86 |
| 13 | TDIndustries, Dallas | $119.04 |
| Piping | ||
| Rank | Company/Location | $Millions |
| 5 | Kinetic Systems Inc., Union City, Calif. | $361.60 |
| 1 | EMCOR Group Inc., Norwalk, Conn. | $129.36 |
| 27 | Harder Mechanical Contractors Inc., Portland, Ore. | $112.04 |
| 8 | PPL Energy Services Holdings LLC, Allentown, Pa. | $95.11 |
| 6 | Limbach Facility Services, Pittsburgh | $89.76 |
| 10 | Southland Industries, Irvine, Calif. | $85.50 |
| 22 | Murphy Co. Mechanical Contractors and Engineers, St. Louis | $81.65 |
| 7 | FirstEnergy Facilities Services Group, Akron, Ohio | $79.60 |
| 31 | JH Kelly LLC, Longview, Wash. | $63.50 |
| 32 | U.S. Engineering Co., Kansas City, Mo. | $60.11 |
| Plumbing | ||
| Rank | Company/Location | $Millions |
| 1 | EMCOR Group Inc., Norwalk, Conn. | $443.52 |
| 3 | American Residential Services/AMS/Rescue Rooter, Downers Grove, Ill. | $310.73 |
| 12 | Roto-Rooter, Cincinnati | $273.84 |
| 2 | Comfort Systems USA Inc., Houston | $106.54 |
| 8 | PPL Energy Services Holdings LLC, Allentown, Pa. | $95.11 |
| 9 | Residential Services Group, Dayton, Ohio | $87.50 |
| 7 | FirstEnergy Facilities Services Group, Akron, Ohio | $79.60 |
| 13 | TDIndustries, Dallas | $74.40 |
| 70 | Ewing-Doherty Mechanical Inc., Bensenville, Ill. | $63.32 |
| 58 | American Plumbing and Mechanical (AMPAM), Round Rock, Texas | $53.00 |
| Sheet Metal | ||
| Rank | Company/Location | $Millions |
| 1 | EMCOR Group Inc., Norwalk, Conn. | $221.76 |
| 10 | Southland Industries, Irvine, Calif. | $99.18 |
| 8 | PPL Energy Services Holdings LLC, Allentown, Pa. | $95.11 |
| 11 | ACCO Engineered Systems Inc., Glendale, Calif. | $94.50 |
| 6 | Limbach Facility Services, Pittsburgh | $89.76 |
| 44 | Kirk & Blum, Cincinnati | $89.70 |
| 7 | FirstEnergy Facilities Services Group, Akron, Ohio | $79.60 |
| 9 | Residential Services Group, Dayton, Ohio | $70.00 |
| 26 | Hill Mechanical Group, Chicago | $65.06 |
| 15 | KeySpan Energy Services, Brooklyn, N.Y. | $38.78 |