Dyna-Glo BF30PMDG 30,000 BTU Liquid Propane Blue Flame Vent Free Wall Heater Liquid Propane Ready (Fuel conversion not permitted) Blue Flame Technology works by convecting heat to warm the air the same way as a central heating system 24,000-30,000 BTU's/hr variable heat output for up to 1,000 sq. ft Variable control knob offers the most customizable heat settings LOW - 24,000 BTU MED - 27,000 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