FYI,
About 10 years ago I had an 8' overhead camper. Space was at a premium. One day I was in Camping World and I passed a section that was displaying a very small electric heater. It was only the size of a 6" cube!
I bought one and have used it ever since. It puts out more heat than any other small electric heater I have ever seen! We have two other electric heaters and this thing puts out more heat than those two
together.
I have not tried it in the TM during sub-freezing weather yet, but last month we used it in 40 degree temps at night and we never had to take out the other heaters or the TM propane heater. We just set the theromstat and forgot it.
Here is a link to where they sell them on Amazon.
http://www.amazon.com/6201-Portable-...1&sr=8-1-fkmr1
Tom