Dyna-Glo IR30PMDG-1 30,000 BTU Liquid Propane Infrared Vent Free Wall Heater Liquid Propane Ready (Fuel conversion not permitted) Infrared Technology works by radiating heat to warm objects first - Similar to the sun 6,000-30,000 BTU's/hr variable heat output for up to 1,000 sq. ft. Variable control knob offers the most customizable heat settings LOW - 6,000 BTU MED - 18,000 BTU HI - 30,000 BTU No electricity required allows for reliable back-up heating incase of an emergency situation Separately sold optional fan (WHF100) improves the amount of square footage the heat reaches in a quiet, yet powerful way! Separately sold optional base legs (WBL100) allows for stable floor mounting 1 Year Warranty