Janeway,

I really don't worry too much about MooShoo getting cold because he does burrow himself under covers whenever he gets cold. I keep my heat at 68-70 degrees and have lots of "snug sacs" around where he can go. When I take him out (he loves to ride in the car) he's got a turtleneck swear that he wears and also snuggles in his little sac. I also have a down throw that he likes too. The rule of thumb is if you're cold, they're cold.

BTW, I'd love to see pictures of your Rexes if you have any. They're almost like Sphynxes with fur.