i'm starting to get into maintenance mode for the winter (i.e. heater turned down to 65.only want it to fire if it were to get below freezing overnight) 3 days ago, my pool temp was at 82...i haven't run the heater since..cover has been on aside from 4 hours yesterday to clean up some gunk and "let the water air". the temp this morning in spite of 3 nights of air temp being below 55, the pool is still at 77 today. i'm impressed!