All outdoor pools utilize passive solar power, which is a fancy way of saying that the pool’s water is warmed by the sun. A more sophisticated, solar system works to more efficiently collect and store heat from the sun.
If you are building a new pool, consider its position in relation to the sun. If it has a good southern exposure, with little shade, then you may not need a heater at all on sunny days. The type of pool cover you use (see Swimming Pool Cleaners & Covers) can also greatly affect the amount of heat stored from the sun.
A solar swimming pool heater is cheaper and easier to install than a solar heater for the house, and, once it is installed, it costs virtually nothing to maintain.
In a typical setup, the solar system is a loop that is bypassed if water in the pool is warm enough; if the water needs heating, a valve sends water through the system. The solar collector is simply a series of flat black panels with metal pipes running through them. The sun heats the panels, which heats the water in the pipes. Consult with your dealer to determine how large the collector should be—usually over half the square footage of the pool itself.
The solar system has two temperature sensors. One senses the temperature of the water in the solar collector; the other senses the temperature of the water in the pool. When the pool sensor decides water needs to be heated, it opens a valve so that water flows through the solar collector before returning to the pool.
A solar system can also be added to a pool’s existing piping. However, check with your dealer to see if you will need a small booster pump as your existing pump may not be strong enough to push water through the added piping.
Of course, solar heat will not operate at night or on a cloudy day. For that reason, many people choose to also have a standard gas heater, which kicks on when the water is cool and the solar collector cannot deliver sufficient heat.
Though the components of a solar system are fairly straightforward, installing one is not a job for amateurs. The components need to be sized and installed correctly. Hire a seasoned pro with a proven track record of successful installations.