Using solar water heaters to heat swimming pools and spas is cost-effective.
Payback can be as low as 2 years, and utility bills are much lower than
they would be using a conventional heating system.
The pool's existing filtration system pumps water through the solar
collectors, and the collected heat is transferred into the pool. Because
solar pool heating collectors operate just slightly warmer than the
surrounding air temperature, these systems typically use inexpensive,
unglazed, low-temperature collectors made from specially formulated
plastic materials. Glazed (glass-covered) solar collectors usually are
not used in pool-heating applications, except for indoor pools, hot
tubs, or spas in colder climates. In some cases, unglazed copper or
copper-aluminum solar collectors are used.
Off-the-shelf packages are generally appropriate, and maintenance of
solar pool heating systems is minimal. The systems are pre-engineered,
and can be sized for any pool by adding additional solar panels for
an adequate solar collector area.
The only moving part on a solar pool heating system is the diverting
valve. This valve controls whether the water circulates through the
collector loop. When the collector temperature is sufficiently greater
than the pool temperature, the water is diverted from the filter systems
through the collector loop. The water bypasses the solar collectors
during nighttime or cloudy periods. Some smaller systems are operated
manually or with timers, but larger systems are operated by electronic
sensors and controls.
Adding a swimming pool cover will further enhance the temperature of
a swimming pool, and should be considered along with the solar pool
heating system to prevent loss of heat to the atmosphere