I am in Clearwater, FL. We use both, a gas heater in the winter to quickly heat up the spa and a solar heater to heat the spa in the summer and to extend the swimming season by about 3 month total. (In the colder month we have to use a blanket to hold the solar heat in the pool over night.)

We are still very happy about both investments.

I hope that one day I will be able to use the heat coming out of the house AC....