I heat a room of 40 m² woth it, it works very well.
I'm testing this heater right now, which arrived amaizingly quickly (10 days to Norway, by DHL). Everything works as described, except from the wattage, which is labeled "5 to 8 KW" (I never expected it to be 8 kW though), but the fuel consumption of about 5.5 dL/h should correspond to around 4.5 kW, which still is pretty decent, at least at this prize. I'm very satisfied so far. NOTE: The exhaust silencer is not by far tight, so it is absolutely required that it is mounted outside the vehicle, and well ventilated.