I have used both the commercially available heated beds and a heating pad underneath layers of cloth and both have been very good for my older kitties. They LOVED the heated beds!

I bought a commercially-produced heated bed (with faux lambskin) from Drs. Foster and Smith and was very happy and satisfied with it.

Generally, I would not leave them plugged in all day every day, but on occasion, I would forget to unplug one or the other or both, and nothing bad happened and my kitties were warm and toasty all day during the cold months here.

Hope this helps.

Robin (aka Biscuit's Mom)