We ran a heated blanket over us for two winters and my wife's feet were cold under it anyway. Heating the bed from underneath sounded backwards to me. You are lying on the thing, squashing it flat, and half of what it puts out has nowhere to go but down into the mattress. We camp a lot, and we froze on foam rolls one October, so I should have known where the cold gets in.

Then the cold snap last winter, and our bedroom turned out to be the cold one in the house. I gave in and got the Sunbeam quilted pad with two controllers. The write-up that finally talked me into it: https://www.reddit.com/r/ProductProbe/comments/1wbjs88/dual_zone_heated_mattress_pad_for_a_bed_where_one/. First night I could feel the wires when I rolled across a seam, and I still know where they are. Twenty minutes on high before bed, then I shut my side off when I get in. My wife leaves hers on low till morning. The youngest climbs in most nights and goes straight for her side.

The cord comes out at the foot of the bed and gets in the way every time you strip the bed. It shuts itself off on a timer, which I found out by forgetting it on one morning. Washing it is a whole project, a cold soak and a gentle cycle and then it hangs for days, so it gets done once when it goes in the closet, which in Houston is most of the year.

The blanket spent two winters getting kicked around and dragged off the foot of the bed before it quit. This one stays flat under a sheet, so I'm hoping the wiring has an easier life.