I bought this as an emergency backup case of a power outage during some recent nasty and cold weather. I ended up testing it out and using it as supplemental heat at night connected to a 20lb cylinder with a hose and inline filter.The heater works great and generates a warm radiant heat. I am sure the fact that the clean combustion of hydrocarbons generates water vapor helped with that warm feeling as moist air feels warmer, especially on a cold winter day when the humidity is typically very low.My place is about 1200 square feet with high ceilings. I left the bedroom door open to make sure there was fresh air for combustion. OF course it isn't rated for a space this large but served as a supplemental heat source and worked quite well.I only have one complaint and this is the only reason I gave it a 4 star rating instead of 5. The heater burns hotter and cleaner on high. I have run this test twice with the same results. If I run on high in my bedroom with the door open, there is no smell and the air seems cleaner. On low, I notice more of a smell, the air doesn't seem fresh, and I woke up feeling kinda puny and with a stopped up nose from being near this thing. I especially notice this smell if I walk outside and then back in. There is not even a hint of this on high. I feel that this might be due to the hotter temps encouraging more complete combustion when burned on high.My only other complaint might be that the range of temps is not continuously variable like a gas grill or stove burner. I suspect this might be so the heater is calibrated to burn as clean as possible on the two settings after my experience on low.All in all, this is a great source of heat and great it burns so clean it can be unvented indoors. It generates PLENTY of heat so I would want to run on low if in a smaller space. My only fear is that it doesn't seem to burn as clean on low so it might be best to open a door/window some in these situations or do the same and run on high.
Rating: [5 of 5 Stars!]