I know I'm gunna get sot down for this but I have mine in a cupboard at the other end of our 21 ft van I'm glad I did . In my opinion putting them under the bed would be very noisy as there is a bit of fan noise and its louder when it starts and when the thermostat cuts it out. There's also a tick from the pump but it's not to bad .
We had ours fitted in our van in a cupboard under the fridge, in the middle of the van 23'6" inside , bit noisy when it winds up , but worth every penny spent . We leave it on low over night and dont get any condensation in van and beautiful and warm in morn. You wont regret it when your in cold places.
We have our unit under our bed. Very little noise. Perhaps the most annoying noise is the tick tick tick noise from the fuel pump. Our pump is instqalled in the front boot, which is adjacent to the bed head.
But we can put up with any sort of noise to enjoy the warmth. of the diesel heater.
Jay&Dee
We never have slept with it on all night, even in the Depths of the Australian Winter. But waking up on a cold morning we switch it on and usually fall asleep again with it on. Never a problem if fitted in correctly.
