Mr. Heater 22,000 BTU Radiant Liquid Propane Workshop Heater HS22L25,000 BTU Mr. Heater Radiant Liquid Propane Workshop Heater HS22L Product Details 99. 9% Fuel Efficient. That is what the Heatstar 22,000 BTU Liquid Propane radiant heater offers. Whether you use it in your garage to keep your cars warm, in your shop to keep the work force busy and comfortable, or in a poultry house eggroom, the Heatstar radiant heater transfers almost all of the fuel it burns directly into clean, safe radiant heat. Utilizing a