Air Temperature Need For Effective Solar Heat

[mas985]

The only thing that really matters is the panel temperature and it needs to be above the pool temp to add heat. There is a correlation between panel temp and air temp but it also depends on air speed, humidity and other factors. I have seen panel temps lower than the air temperature (cloudy days) and up to 20 degrees hotter than the air temp so it is difficult to say exactly what you should expect. The best thing to do is put a thermometer on the panels to see what the temp is.

[Xndman]

One last question, I assume I should run the water through the heater on low speed (not high).

Thanks!!

[mas985]

Actually, heat transfer is better at higher flow since less heat is lost to the air when the panels are cooler. However, for energy reasons, you may still want to operate at low speed. If the panels are not excessively hot, then this is still efficient.