| | Duratherm Processing Systems (Saint Charles, IL) Heaters & thermocouples for plastic mold industry | |
| | Durex Industries (Cary, IL) Manufactures wire thermocouples & industrial electric heaters | |
| | Electra Inc (Chicago, IL) Water heaters | |
| | Electra Tek Corp (La Porte, IN) Electric heaters | |
| | Enerco Technical Product Inc (Cleveland, OH) Manufactures heating & ventilating equipment; industrial infrared, portable & camping heaters | |
| | Fostoria Industries Inc (Fostoria, OH) Gas & electric infrared heating equipment, industrial & commercial lighting, process heating ovens & explosion proof heaters; metal stampings | |
| | Glenn Electric Heater Corp (Erie, PA) Industrial heaters | |
| | Glo-Quartz Electric Heater Co (Mentor, OH) Tubular heating elements, immersion heaters & infrared heating equipment | |
| | Grid Industrial Heating Inc (Salem, OH) Industrial cast iron steam unit heaters | |
| | Hannon Electric Co (Canton, OH) Mechanical & electrical apparatus repairing, high voltage test equipment, transformers, screen heaters & glove testers | |
| | Hardwood Line Mfg Co (Chicago, IL) Electroplating equipment: plating barrels, tanks, heaters, linings & coils | |
| | Hatco Corp (Milwaukee, WI) Electric booster water heaters for commercial dishwashers, third compartment sink heaters; electric conveyorized toasters, food warmers, holding & display cabinets; cook & hold ovens | |
| | Heat Wagon Inc (Valparaiso, IN) Portable heaters | |
| | Heater Meal Co (Springdale, OH) Military powered heating substances, flame less ration heaters & packaged food with flames less heating devices | |
| | Hotset Corp (Battle Creek, MI) Cartridge, coil, band, strip & tubular heaters; temperature controls; thermocouples; connectors | |
