"This HeatStar Propane Heater provides efficient, cost-effective heat for loading docks, warehouses, factories, pole barns and more. Blower Included No, Gas Inlet in. 1/2, Needs Direct Venting No, Igniter Yes, Clearance from Rear Wall in. 30, Clearance from Side Wall in. 30, BTU Output 40,000, Blower Power Supply Volts, Amps 110V, Dimensions L x W x H in. 30 1/4 x 19 1/4 x 12, Product Type Radiant heat, Thermostat Included No, Clearance from Corner in. 30, Heating Capability sq. ft. 750, Oxygen Depletion Sensor No. No direct venting required Durable construction Quiet, clean heat Maintenance-free design Includes extra orifice for increasing BTU output Requires 24 Volt thermostat to operate Item# 16342 sold separately"