I bought 2 in order to weather through below freezing Temps at our ranch for a 400sqft trailer. After reading reviews ofa mixed nature I thought 2 would be best. Halfway through the night, approx 26 degrees out.. I am toasty at half power! My daughter complained that it was too warm and she woke up sweating. 13 hours, and 2/3 tank used. Efficient and easy to use. The two of them at full power use about 400peak watts for startup, after a few minutes level out at 80w per hour. Quiet operation, the ticking isn't that bad, I couldn't even hear it once in bed with my wife's Alexa playing a soft rainstorm as background sounds. I mounted the units outside and piped through a port into the trailer. Hands down, beats propane heaters!