I had purchased two of these for my RV garage with the intention of keeping the internal temp from dropping below freezing. I live in the gulf south, and we rarely see below freezing temps, nonetheless, I was previously using propane to keep the temps above, which could get quite expensive. These heaters only sip the diesel, which here is quite cheap. I extended the exhaust pipe by 6 meters and coiled it to radiate exhaust heat. I then vented the exhaust through a window using a marine bulkhead fitting onto a board which worked quite well to seal the window opening. Two heaters successfully kept the garage above freezing.