Heat water with Propex heater?

@ Handbasket , I really like the Propex , my van is insulated pretty good except the cab portian and the Propex keeps me warm in the winter , the cab area stays kind of chilli , as for noise you just hear the fan which is' nt very loud and you also hear a constant rush of hot air blowing out which is a relief .
It sounds like a hot air balloon being heated up except much more quiet.