How do I insulate an ultra therm?

[Matt]

Just got an ultra therm for my tank and have taped it to the back like the paper that came with it said. I have read that insulating it can make it hotter, how do you do this and what do you do it with? Thanks!

[JulesRolyCrab]

I wrapped a piece of cardboard the size of the mat completely with aluminum foil and taped it to the Ultratherm with packing tape. Some people use thick Styrofoam. I didn't because I was worried that it is more flammable than other materials, but I don't think I've heard of anyone having issues.

[megmaholm]

I tape the Ultratherm onto the tank, tape a layer of aluminum foil over it, then tape on thick Styrofoam. Works for both my tanks without any issues.