Willow has beds all over the house. Some she uses more in summer and others more in winter. Usually on winter mornings she will usually sleep on her bed that is next to the heat vent and afternoons in the darkest, coziest place in the house, the linen closet.
I have a small electric fireplace. The cats all like to "roast" in front of it when I turn it on. The bathrooms have small hot water heaters that work off the domestic hot water. They will sometimes sit in front of those as well.
I tell people that the day I put the electric blanket on the bed is the last time I expect to see Hekitty until Spring. It's a joke. Sort of. If I'm working in the office, she curls in her heated bed, but otherwise, I see her at meal times, a couple of times in the evening for lap time, and at bedtime. My gal loves her "warms."
Carleton knows exactly where to go depending on the season, in winter he is upstairs where it's warmer and in summer he's downstairs where it's cooler. On cold wintry days he sleeps with us at night and on the top of the stair in the daytime.