We have a Delonghi MicaThermic heater. It has no flame, no glowing parts, consumes no oxygen, makes no carbon monoxide, is very lightweight, and makes no noise at all, as there is no fan. It is the size, shape and thickness of a flat screen TV and can be wall mounted. In fact, we have ours mounted in our TT bedroom where the TV would be mounted. It provides ample heat, but does not provide immediate quick heat. One heater kept a 26 foot TT very warm when the nights got down to about 25 degrees Last fall.
Here's a photo:
And here's a link to the heater on Amazon:
Amazon linkAlthough we bought two of these at an outlet store for considerably cheaper - $20 each.