Would I harm my temperpedic like foam mattress topper by using an electric mattress pad?

I also use a heated mattress pad. But I do not use a foam topper, so I cannot say for sure. But I have a suggestion, if you get a mattress cover for the foam, then it should be insulated against the heat. Then the two will not be against each other.
Just an idea, sorry I couldn’t help further.

I use a heated mattress pad and a foam topper and have never had any problems with the heat damaging the foam. If you’re worried, what you can do is put a regular mattress pad on top of the foam topper and the heated pad on top of that; this will create a bit more of a barrier between the electric mattress pad and the foam itself.

I love my heated mattress pad! It’s a life saver on these cold winter nights.

Heat and foam do not mix. the heat from the heated mattress pad will eventually dry out the foam.

Somewhere, i read an article about electric blankets not being safe for humans. this is why very few are being made today.

@john65pennington – my 90 YO parents have been using electric blankets for over 65 years. and I am talking about an electric mattress pad.

It is perfectly safe to use an electic blanket with foam however if it is memory foam like Tempur then the heat may make the mattress softer than you are used to.