Mr. Heater F260560 Big Maxx MHU80NG Natural Gas Unit Heater Easy outside access to thermostat and A/C terminals. 0.5 inch gas connection Limited 3 year warranty on parts and burners Powered exhaust allows for vertical or horizontal venting Natural Gas to Liquid Propane conversion kit included 80,000 BTU per hour heats up to 2,000 sq. ft.