I tend to sleep pretty hot, especially with the memory foam mattress we have. I actually looked into bed coolers at one point. A few companies make refrigerated bed chillers. They have a pad with tubes embedded in it that circulate fluid from a unit positioned next to the bed. They’re fairly pricey.

I almost got one, but I ended up trying something different. The devices tend to be pretty complex, often unreliable, and chained to spyware apps. Leaks in the lines can cause mold, and often they require regular cleaning by flushing cleaning solution through the lines.

Ultimately, I found a much simpler, reliable, and low tech solution - classic rubber hot water bottles. I have two rubber hot water bottles. I keep them full of water. Before bed, I’ll take them out of the freezer. In the morning, I put them back in the freezer. They do a great job of keeping the bed cool. Now, you don’t want to have a big block of ice in direct contact with your skin while sleeping. To avoid this, the bottles have an outer cloth case. There’s lots of different varieties of these bottles, but these are the ones I tried and have worked well for me.