2 years ago I bought an electric mattress pad. My wife gave me a hard time about it at first, didn't think we'd ever use it.

But wow. Nothing better than climbing into a preheated bed on a cold night. I always set it to high about 20 minutes before we actually go to bed, then turn it down to the lowest setting. When it's cold out, every single time we get into bed, we both let out a sigh of comfort. Can't recommend it enough.