Poor Man's Spray Foam Insulation

I filled my entire trailer walls with Styrofoam board. This stuff has become expensive in 4x8 sheet at Lowes. I get free foam from furniture store dumpsters it comes in many different sizes and thickness, there are lots of flat sheets from 1/2" to 1.5" thick.  Styrofoam is flexible and compressible. I cut it slightly too large for the hole after pushing it in tight air leaks are sealed off. It bends easy in the curved areas push it in tight it stays where it is put. I cut the thick Styrofoam down to size with my hand saw.  I build a cutting fixture with wood like a miter box for cutting Styrofoam in 1.5" thick slices with the hand saw. Slide the Styrofoam into the fixture to the stops then cut off the end.  Keep sliding the Styrofoam in and cutting the end off.

Do not cut Styrofoam with a table saw, the friction of the blade melts the Styrofoam a tiny bit just enough to increase friction then it sticks to the 3400 RPM blade.  Styrofoam will jam the blade then the Styrofoam is thrown out.  If your holding it too tight it can jerk your fingers into the blade or throw the Styrofoam back into your face. 

Our camper is warm as toast. It was 37 degrees on our first camping trips I did not turn the electric heater on until about 2 am.  I turned it on low and had a hard time getting the 1 to 10 dial set to the correct temperature it only took 5 minutes for the camper to be too hot.