At least you're in an area that doesn't see below freezing during the winter.

I've seen a few videos of how hot tubs are built, here's one:

https://www.youtube.com/watch?v=hNBuqtAlP64

While I understand the purpose of spray foam insulation to reduce heat loss, what happens when there's a leak? You have to dig though all that insulation to find and fix a leak. Sounds like fun.

My neighbor has one, his pump needs work every two years. Granted, it runs all through the winter.

To top it off, my neighbor or his wife don't use it as often as when they first bought it so the novelty wore off.

Maybe ask around your neighborhood?

Mike.