We have sloar panels on the roof that are valved into the filtration system. The solar contractor who installed them complained a bit that they were too small (all the roof we had available) but I had 1/4" foam installed on the walls and under the floor and we have the solar cover on whenever we're not in the pool. We are very happy so far, we've had pretty bad weather (hurricanes and rainstorms that dumped as much as hurricanes) since the system went in but it's given us several swim days that we wouldn't have had otherwise.