I have one of these and find that it's better than a propane heater. I have the 15" model and use it in my 10 gallon Blichmann boiler maker. I turn it on when sparging and the wort covers the heating element. When half way done with the sparge, about 3.25 gallons, I turn on the boil switch. It takes about 45 minutes for the 6.5 gallons to boil. Evaporation rate is about a gallon an hour. The best part is that I can brew inside and I'm not at the mercy of the weather. I use it to heat my sparge water too.