How do you avoid the fumes and CO ?
Excellent question. They use a heat exchanger so the combustion gas is completely separated from the heated air. A combustion air supply and exhaust must be routed to the unit to outside air. They are essentially an miniaturized oil furnace like what you might have in your home. I think I will mount mine on the drivers side opposite the fuel tank under the rear seat so it is outside, below the fuel tank and in a good location for the air supply to be piped into the cab.