Insulating pad for inflatable hot tub

Question

I got an inflatable hot tub which I want to place on an existing concrete surface.

However, I am concerned about heat loss since concrete is a fairly good thermal conductor. I would like to insulate it as best as possible.

What is the easiest way to do this?

I was thinking of getting rigid foam board insulation such as this. I could get 1 or two boards and cut a circular pad, nicely matching the shake of the hot tub. Is this a bad idea?

Answer 1

Not only energy loss but the concrete will damage the bottom of the tub.

Use interlocking exercise floor mats. Lightweight foam ones are cheap and sufficient for this job.