How does a solar Pool heating system work ...

During the day a pump circulates the water from the swimming pool and through a solar panel(s) where the heat from the sun is collected and transferred to the circulating water.

Solar Swimming Pool Heaters Perfect For South Africa

In South Africa because we have so much sun water tends to get nice and warm and becomes perfect for lounging in the garden swimming pool. When the sun sets the radiation form the sun also stops so no further warming can take place.

At this stage to conserve energy and water temperature the pump circulating water should be stopped. In South Africa pool temperatures of 30 degrees C are normally achieved easily. It is possible to install a control system that will stop and start the pump depending upon the temperature in the swimming pool.

How do I know what size solar heating system to buy?

The bigger the pool the bigger the unit required. However the sizing is not just a function of the pool size but also daytime and night-time temperatures. In practice the solar heater is normally placed onto a roof having a northern elevation (South Africa) or a southern elevation if you live in northern hemisphere so the size and pitch of the roof might also be a limiting factor. If you install a pool cover then heat loss at night will be reduced so a smaller unit could be used to maintain a reasonable temperature.

Because the energy from the sun is free the cost of running a solar swimming pool heater is restricted to the power used to drive the circulating pump.

Whatever the manufacturer or installer says also insist upon references and a solid written guarantee and this should include possible hail damage ... the collector is often covered with a glass sheet.