Sean, not to sound like a commercial but I have an AquaCal Heatwave Icebreaker 120 on my pool and spa. It's great. It will heat my spa to 104 in about 10 minutes during the summer and in the winter when it was just below 50 degrees it took my spa from 65 degrees to 100 degrees in about 25 minutes! Still waiting for my pool to get hot enough to try out the reverse cycle cooling feature this summer!