This solar heated in-ground 40 x 20 foot pool was built in 1975 by Apollo Pools and was purchased by the current owner with the pool and solar heating system already installed. The only work they have done to the pool heating system is to maintain the solar panels and upgrade the control system to reflect more recent innovations and developments. Solar heat is the only heating system used for this pool and, with occasional exceptions during extended cloudy periods, it maintains a constant water temperature in the high 80's (Fahrenheit) from about June 1 to about September 1, depending on the weather in any given year.

The solar heating for this swimming pool consists of eleven, 4 x 8 foot unglazed (no glass) solar panels on the roof of the house. The exposure is north-west. Water is electrically pumped from the pool. The water goes through a normal filtration system, but before it returns to the swimming pool, it has the option, depending on signals from the solar control panel to first be pumped up to the roof where it is heated by sun before returning. That is a typical water route. The pool water will bypass the solar panels if the in-line thermostat determines the water in the pool is already at the desired temperature, or if the water in the solar panels is at a lower temperature than the water in the pool. The pool is covered every night with a solar blanket to retard heat loss.

Unlike solar domestic water heating systems, which raise a small amount of water to a high temperature of 140°F, pool heaters raise the temperature of several thousand gallons of water to a warm 80°F by circulating the water at a relatively fast rate through the collectors. This allows most of the solar energy falling on the collectors to transfer to the pool water so that even unglazed collectors are efficient.

The rule of thumb for pool heating is ½ of the surface area of the pool should be provided in collector area. Covering the pool when it's not in use can save up to 90% of the energy by reducing evaporation (a big heat loss). Solar pool heating extends the swimming seasons for these home owners by at least 2 months.