I'd be cautious my tenants in my investment property had one and theirs caught fire, luckily she wasn't asleep yet when it started smoking, she was able to get out and save her children (who were also in the bed) she lost her mattress and bedding through it though.
I had one on my Queen and I would use it to preheat the bed before getting in of a night. Ours was a fluffy wool one, just gorgeous even in summer as an underlay.
Bookmarks