How Solar Pool Heaters Work

Solar pool heaters operate in a simple manner.  Cold water is pumped from your pool through a solar panel located on the roof or on the ground where it is heated by thermal energy collected from the sun.   Desired pool temperatures range from 72 F to 85 F.  The warm water is then pumped back into your pool providing warm water and extending the swim season.Schematic a

Most solar pool heaters include the following:

  • A solar collector — the device through which pool water is circulated to be heated by the sun;
  • A filter — removes debris before water is pumped through the collector;
  • A pump — circulates water through the filter and collector and back to the pool;
  • A flow control valve — automatic or manual device that diverts pool water through the solar collector;
Source: Dept. of Energy

Source: Dept. of Energy

Pool water is pumped through the filter and then through the solar collector(s), where it is heated before it is returned to the pool. In hot climates, the collector(s) can also be used to cool the pool during peak summer months by circulating the water through the collector(s) at night.

More advanced systems include sensors and an automatic valve to control water flow through the collector(s).   When the collector temperature is sufficiently higher than the pool temperature, water flows through the collector.  When the collector temperature is similar to the pool temperature, filtered water simply bypasses the collector(s) and is returned to the pool.

  1. Set your preferred pool water temperature;
  2. Sensor identifies most efficient time to run;
  3. The pool pump sends cold water from the pool through solar collectors;
  4. Solar collectors heat the water;
  5. Warm, solar heated water flows back to your pool.

Since all swimming pools require a pump and related plumbing, the addition of a solar pool heater to an existing installation can be relatively simple.  However, unless you are experienced with plumbing and electrical wiring, it s advisable to allow a professional to install your system.  Often the existing filter pump can be used to circulate the pool water, though you should be sure it is able to maintain a high flow rate in order to keep the panels cool and operating at a high efficiency. It is generally recommended that all the pool water circulate through the collectors every 8 – 12 hours. Your collector should require very little maintenance provided the pool’s chemical balance and filtration system are regularly checked.