This Prodigy spa, is our second spa from Hot Springs. Our first one we had in Florida and we enjoyed it so much we had to have another one. We stuck with the brand we knew and trusted and are extremely pleased.We have enjoyed it even on snowy nights here in the Pocono region of Pa. We have sat in the spa many nights even with the temperature as low as -18F, and have enjoyed the warmth of our spa. I am pleased with the thermal efficiency of this unit,and have estimated that through the winter it has only cost us about a dollar a day to maintain this unit. (And we use it about 5 nights a week and it is outside on our deck right in the weather.) Sign us as happy owners….