| STS T Johnson Company | Oakland | CA | — | ◇ UNVERIFIED |
| STS T Johnson Company LLC | Fairfield | CA | — | ◇ UNVERIFIED |
| SDStove Depot and Chimney Works LLP | Grand Junction | CO | — | ◇ UNVERIFIED |
| SSubmer | Sausalito | CA | — | ◇ UNVERIFIED |
| SSSundog Solar LLC | Searsport | ME | — | ◇ UNVERIFIED |
| SCSunergy California, LLC. | Sacramento | CA | — | ◇ UNVERIFIED |
| SMSun Mountain Stove Works INC. | Creswell | OR | — | ◇ UNVERIFIED |
| SISuntrek Industries INC | Irvine | CA | — | ◇ UNVERIFIED |
| SHSuperior Holding INC | Hutchinson | KS | — | ◇ UNVERIFIED |
| SMSupertech Machining INC | Chatsworth | CA | — | ◇ UNVERIFIED |
| SHSutter Home & Hearth | Seattle | WA | — | ◇ UNVERIFIED |
 Swanson Industries, INC | Madisonville | KY | — | ◇ UNVERIFIED |
| SFSynder Filtration | Vacaville | CA | — | ◇ UNVERIFIED |
| TCTank Construction & Engineering INC | Fresno | CA | — | ◇ UNVERIFIED |
| TITechno-solis, INC. | Saint Petersburg | FL | — | ◇ UNVERIFIED |
| TCTechnotherm CORP. | Tulsa | OK | — | ◇ UNVERIFIED |
| TCTei Construction Services, INC. | Royersford | PA | — | ◇ UNVERIFIED |
| TPTemtex Products INC. | Nashville | TN | — | ◇ UNVERIFIED |
| TLTerex Light Contruction | Rock Hill | SC | — | ◇ UNVERIFIED |
| TYTerry York | Shelbyville | TN | — | ◇ UNVERIFIED |
| TBThe Blue Rooster Company | Nevis | MN | — | ◇ UNVERIFIED |
| TCThe Center | Colville | WA | — | ◇ UNVERIFIED |
 Thermal Engineering International (usa), INC. a Subsidary of Babcock Power | Sapulpa | OK | — | ◇ UNVERIFIED |
| TLThermamasters, LLC. | Wetumpka | AL | — | ◇ UNVERIFIED |
| TCThermasys Corporation | Iron Ridge | WI | — | ◇ UNVERIFIED |
| TTTherm Tec INC | Sherwood | OR | — | ◇ UNVERIFIED |
| TBThomas & Betts Corp/reznor-mercer Plt | Mercer | PA | — | ◇ UNVERIFIED |
| THThompson's Hearth & Home | Issaquah | WA | — | ◇ UNVERIFIED |
| TSTractor Supply CO. | Bloomington | IN | — | ◇ UNVERIFIED |
| TSTractor Supply Company #2055 | Kent | WA | — | ◇ UNVERIFIED |
| TUTrane US INC | Salt Lake City | UT | — | ◇ UNVERIFIED |
| TITravis Industries | Mukilteo | WA | — | ◇ UNVERIFIED |
| TITravis Industries | Mukilteo | WA | — | ◇ UNVERIFIED |
| TTTriangle Tube/phase Iii CO INC | Blackwood | NJ | — | ◇ UNVERIFIED |
| TSTriple S & P, INC. | Duette | FL | — | ◇ UNVERIFIED |
| TPTri Precision Sheetmetal INC | Orange | CA | — | ◇ UNVERIFIED |
| TSTrue Solar USA | Santa Clara | CA | — | ◇ UNVERIFIED |
| TSTru Sheet Metal, INC. | Ronkonkoma | NY | — | ◇ UNVERIFIED |
| TTTsm Thermal Solutions Mfg | Livonia | MI | — | ◇ UNVERIFIED |
| THTulsa Heaters, INC. | Tulsa | OK | — | ◇ UNVERIFIED |
| T3Turbo 3d LLC Dba Fugo | Gardena | CA | — | ◇ UNVERIFIED |
| TPTurbotec Products INC. | Windsor | CT | — | ◇ UNVERIFIED |
| TETurner Equipment Company, INC. | Goldsboro | NC | — | ◇ UNVERIFIED |
| TCTwin City Edina Fireplace Showroom | Edina | MN | — | ◇ UNVERIFIED |
| TITylohelo INC | Cokato | MN | — | ◇ UNVERIFIED |
| UAUltratech a Division of Veeco | San Jose | CA | — | ◇ UNVERIFIED |
| UIUltratech, INC | San Jose | CA | — | ◇ UNVERIFIED |
| UCUnifin Chesapeake | Chesapeake | VA | — | ◇ UNVERIFIED |
| UDUniversal Dynamics | Woodbridge | VA | — | ◇ UNVERIFIED |
| UAUS Army Garrison West Point | West Point | NY | — | ◇ UNVERIFIED |
| USU S Radiator Corporation | Los Angeles | CA | — | ◇ UNVERIFIED |
| UAUss Annapolis - Cal. Marine | San Diego | CA | — | ◇ UNVERIFIED |
| USU.s. Sheetmetal INC. | West Bridgewater | MA | — | ◇ UNVERIFIED |
| UVUS Va Hudson Valley Health Care System - Castle Point Campus | Wappingers Falls | NY | — | ◇ UNVERIFIED |
| UTUtility Trailer Sales of Central California INC | Lathrop | CA | — | ◇ UNVERIFIED |
| VPVapor Power International | Franklin Park | IL | — | ◇ UNVERIFIED |
| VFVelcon Filters INC | Colorado Springs | CO | — | ◇ UNVERIFIED |
| VPViking Processing CORP | Fontana | CA | — | ◇ UNVERIFIED |
| VHVolcanic Heater, INC. | Alliance | OH | — | ◇ UNVERIFIED |
| VFVulcan Finned Tubes L.p. | Tomball | TX | — | ◇ UNVERIFIED |
| WBWa317937098 - Blaze King Industries INC | Walla Walla | WA | — | ◇ UNVERIFIED |
| WSWa317937125 - Snorkel Stove Company the | Seattle | WA | — | ◇ UNVERIFIED |
| WIWa317938400 - Innovative Hearth Products LLC | Auburn | WA | — | ◇ UNVERIFIED |
| WTWa317941846 - Travis Industries INC | Mukilteo | WA | — | ◇ UNVERIFIED |
| WSWalter Snedeker, INC. | Chickasha | OK | — | ◇ UNVERIFIED |
| WFWarehouse-waste From Mexico | El Paso | TX | — | ◇ UNVERIFIED |
| WTWarming Trends, LLC | Englewood | CO | — | ◇ UNVERIFIED |
| WTWarming Trends, LLC | Englewood | CO | — | ◇ UNVERIFIED |
| WHWatlow Heater Technology Center | Fenton | MO | — | ◇ UNVERIFIED |
| WFWatts Fort Worth | Fort Worth | TX | — | ◇ UNVERIFIED |
| WRWatts Radiant | Springfield | MO | — | ◇ UNVERIFIED |
| WWWatts Water Technologies INC | Hudson | MI | — | ◇ UNVERIFIED |
| WCWayne Combustion Systems | Fort Wayne | IN | — | ◇ UNVERIFIED |
| WIWcr, INC. | Macon | GA | — | ◇ UNVERIFIED |
| WIWcr Incorporated | Seward | NE | — | ◇ UNVERIFIED |
| WIWcr Incorporated | Fresno | CA | — | ◇ UNVERIFIED |
| WCWebster Combustion Technology, LLC (stormwater) | Winfield | KS | — | ◇ UNVERIFIED |
| WIWellons INC | Sherwood | OR | — | ◇ UNVERIFIED |
| WCWest Coast Steel & Processing Dba Great Pacific Elbow | Chino | CA | — | ◇ UNVERIFIED |
| WMWickes Mfg CO | Beardstown | IL | — | ◇ UNVERIFIED |
| WFWilkening Fireplace CO | Walker | MN | — | ◇ UNVERIFIED |
| WDWilliams & Davis Boilers | Hutchins | TX | — | ◇ UNVERIFIED |
| WFWilliams Furnace CO | Colton | CA | — | ◇ UNVERIFIED |
| WEWolfe Engineering, INC. | San Jose | CA | — | ◇ UNVERIFIED |
| YFYankee Fireplace Grill & Patio | Middleton | MA | — | ◇ UNVERIFIED |
| YIYork International Pace Division Site | Portland | OR | — | ◇ UNVERIFIED |
| YSYork Shipley | Hampton | VA | — | ◇ UNVERIFIED |
| YEYoung Engineering & Manufacturing INC | San Dimas | CA | — | ◇ UNVERIFIED |
| ZZiggy's | Spokane | WA | — | ◇ UNVERIFIED |
