I installed this in my 5th wheel RV. I put it in the belly storage area and ran a 4 inch insulated duct. It's not cold here yet but the thermometer red 134 at the vent before I shut it off. The fuel pump is a bit lound and I feel that is resonating through the mount. I am going to try using felt washers to space it off the wall. So far, I would recommend this heater. UPDATE : I split the duct 3 ways. One to the bath/bedroom area, one to the living area, and one small one to underneath to heat the waste water tanks. This unit is a bit undersized for what I did. The hear system works great and I'm thinking of giving the 8kw size a try. At 25 outside, this heater only held a 60 inside temp. In my 30ft 5th wheel with one big slide out. Vent temp is over 150. A stronger fan might work better, to recirculate the air more.