I had a used Nordic. I can't remember the model, but definatly thier lowest end (round, 35" deep and about 12 jets). It was built in 1999. I got it free third hand. It cost me a forturne to heat in the winter. There was no insulation in the cabinet other than some spay on foam on the shell.
They look now that they are full foamed?
I have to say, for a low end spa, I had a ball in it (but I didn't know any better
That is until the electric bills came in.