I recently installed this heater in my 16 x 22 detached garage as the primary heat source. (ceiling and walls are well insulated) I couldn't be more pleased with its performance so far. Initially, I used a thermometer to check temperatures at various settings on the heater. For me, the difference in the setting numbers is about 10 degrees. It keeps my building at a nice 50 degrees when I'm not in it; and a comfortable 60-65 when I turn it up while inside. We've had a few days with high temperatures only reaching single digits- and the temperature inside only varied about five degrees. Great heater for a small garage.