85,000 BTU’s provide constant forced air heat ducted into tents with the heater placed outside the tent or structure. In average climate, this heater provides enough heat to easily warm an enclosed area of 1,000 to 1,200 square feet. On/Off switch is conveniently mounted to a tent leg. Requires 6-amps to power fan. Lasts approximately four hours with it 10-gallon propane tank.