I've thought up a nice warm remedy for all you cold houses up there, pretty simple and cheap, as well. You don't need a heating pad or anything, though this might not be as high tech, but it'lll do
It's kinda simple, really. What you do is take an old or new or one you're just not using blanket (not too thin) and cut two round sheets equal in size to fit in your kittehbed. You can use a sewing machine or by hand, but make sure it's tight in gaps and sew together by the edges but leave a hole about...five inches big, I would say, around the edge also. Pour in a bunch of beans, or small pebbles. Beans work best. And I don't men like huge falva beans, I mean like kidney-bean sized. So fill the little round packet you've made so it's not overstuffed, but not too many spaces, either (so that when you lay it flat and smooth it out, it's relitavely flat and maybe a teeeeeny bit poofy if you want it firmer (for example if your kitty likes softer, a few less beans; firmer, a few more). When you're done filling it up, sew up the hole and put it in the microwave (for as long as needed, but not so long as to boil ._.;) so it's nice and warm. When you put it in your kitty bed and your kitty sits in it, it will mold to kitty's body and make it nice and warrrm. Heat again as necesarry ;3.
Hope this works for you guys!