The best way to control a solar pool heat system is with an automatic controller. If you do not have one, you are missing out on great convenience, and not maximizing your solar pool heating investment. Most people who do not have a controller just leave their solar pool heating system all the time. That means any time the pump is running, water is flowing through the solar panels.

Unfortunately, solar panels can also act like a radiator, giving pool heat back to the atmosphere. On very cloudy days or during rain, you may actually be cooling your pool if you solar pool heater is running. Usually this is not a huge problem, but it is definitely less than optimal.

One thing you can do is set your pump timer with ideal times to run the pump when you are most likely to get good performance from your solar panels. If your panels are mounted on the south roof, 10:00 am – 2:00 pm are the prime hours, and you pump should be run during this time. If your panels are mounted on the east roof, you will want to start you pump a bit earlier, and definitely don’t run it too late. The biggest mistake I see is when panels are mounted on a southwest or west roof, and the homeowner has the pump set to start at 8:00 am. On a cool morning with no sun hitting the panels, some cooling is highly likely. I recommend no earlier than 10:00 am for a pump start time, but the stop time depends on the time of year.

The best thing to do is observe your panels and make sure you pump is running when the sun is hitting them. Shading and time of day are important to evaluate.

Again, an automatic controller is your best option for controlling your solar pool heat, but if you aren’t willing to make that investment, take some simple steps to maximize your system’s performance!