So far I have been very impressed with this wood furnace. It has been capable of heating my 3500 ft.² home to 80°F when it was 15° below zero Fahrenheit, when asking it to do so. Obviously, that is not common practice to heat the home that much but I was interested in testing its potential. I normally keep my thermostat at about 72°F. I have yet to pack the wood box completely full of wood as there is no need to do so because it efficiently utilizes the loads I have been putting in it thus far, therefore, not forcing me to pack it to full. My father has a wood furnace from when he built his house in 1989 and when speaking with him, I estimated I have used about one third the amount of wood that he has in about a week's time. If the unit holds up and does not give me any complications and the firebox does not crack at the welds, this will be a very good purchase.