Features and Benefits:400,000 BTUs heat up to 5,763 sq ft;For use with natural gas, includes NG to LP conversion kit;Includes ceiling mounting brackets;High temperature safety shut-off switch and gas safety shut-off flame sensor;CSA certified;HeatStar Big Boxx 400,000 BTU unit heater will turn your garage or barn into a work space you can use all year-round. Uses a built-in high velocity electric fan to pull cool air in and across the heat exchanger, then forces warm, comfortable air out. Its low profile design requires only a 10 ft minimum ceiling height and 1 in. mounting clearance. Features a high temperature safety shut-off, gas safety shut-off flame sensor, and an electric spark ignition with self-diagnostic control module, to bring you peace of mind and years of comfortable, safe heat. Comes as natural gas and includes a propane conversion kit and ceiling mounting brackets. Requires 115-Volt AC power and can be vented vertically or horizontally - please check local codes and restrictions. This heater offers all the operating versatility and safety you have come to expect from Mr. Heater.