I purchase this to heat an oversized 3 car garage. I live in the mountains in Colorado so I wasn't expecting a heater that would keep my garage at 70 degrees. My garage is very well insulated but with no heat source the temps can fall to 30 degrees inside when it is zero or below outside. My only issue was finding a place to run the exhaust. I wasn't sure where I would install it so I chose by a window as a temp location and there was an outlet there. I made a hole in a board and added a 3/4 in copper pipe to the exhaust so that I it would fit in the window and so far it seems to work. The exhaust pipe gets very hot, to the point I am a bit worried about the wood as it does burn, so I will probably make something out of metal when I decide on the permanent location I have only used it about 3-4 times so far this winter as I bought it in January. My garage is approx 30' x 30' with 9ft ceilings and after a couple hours this thing will bring the temperature up by 10 degrees. It blows very hot air. The longest I let it run was about 8 hrs when it was approx 15-20 degees outside. My garage stayed a comfortable 55 degrees. The things that you don't always read about are: the small pump does make a clicking noise all the time the heater is running. The higher you raise the electronic temp control the faster the clicking will be. Set up was simple, I did have an issue with error code when I first stated it up. Code read the fan/impeller might be stuck and sure enough it was. I turned it with my hand and its been running since. It takes a bit longer to prime the pump then you think so be patient untill ALL the bubbles are gone! I added a 12v power supply from Amazon so that I wouldn't have to use a battery, these seems like a pretty common add on from all the reviews and videos I have seen. I really find this device somewhat amazing. The size and amount of heat it puts out is incredible. I don't know how long this will last but for the price it seems to me to be a great choice. I may end of buying another one to heat the garage quicker. I feel the cost of operation is probably less than running a 10,000 watt electric heater or the amount of natural gas I would use had I chose to go that route, not to mention the cost of an electrician or plumber to run gas line. The heater doesn't take up a lot of room so it can be mounted most anywhere if you buy the one you assemble. You can chose the pre-assembled portable one which may make more sense. I gave this 5 stars for price, ease of use and features. I gave a 3 for quality as I haven't seen how long it will last but can adjust upward if its still running next winter.
joe 
