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Solar Heater

See also: Categories: Swimming Pool Equipment, Pool Heating


Solar swimming pool heating systems obtain their heat from the sun and mostly benefit consumers who live in very sunny areas. Environmentally friendly solar heating is a popular solution due to utilizing free energy from the sun.


Solar heating is perfect for those recreational pool owners looking for a heating system that has minimal operating cost and which provides a warm pool when people most want to swim. That is, on fine summer days. After the initial installation cost, the only additional expense is the operation of the swimming pool booster pump (which most manufacturers recommend). Because of its reliance on weather conditions, the solar system will provide a consistency of temperature in summer and a variable temperature rise at the edges of the season in late spring and early autumn.

When considering the installation of a solar heater, the all-important factors are the collector area proposed, collector design and quality of material. There is only a fixed rate at which the sun will provide energy, so the larger the collector the more heat will be gained. As a general rule the collector should be equal to at least 80% of the area of the pool, although 100% coverage would be more typical. Results improve as the collector size is increased. Other points that are important when considering solar are the pitch and directional aspect of the roof, that is, which way it faces. A roof facing north is most favorable because it will receive the maximum amount of sunlight. Any shading of the roof by large trees will also be considered. The location of the pool and how much it is affected by shade and wind is also important.

How does it work

Solar heaters use solar panels to transfer heat from the sun to your swimming pool. As solar panels sit in the sun, they collect heat. Then, the swimming pool pump pushes water through the circulation system and through the solar panels. As the water passes through the solar panels, it heats. Because of solar heaters’ reliance on the sun, many swimming pool owners use auxiliary heaters during nights and cloudy days.

Most solar pool heating systems include the following:

  • Solar collector — the device through which pool water is circulated to be heated by the sun
  • Filter — removes debris before water is pumped through the collector
  • Pump — circulates water through the filter and collector and back to the pool
  • Flow control valve — automatic or manual device that diverts pool water through the solar collector.

Some systems include sensors and an automatic or manual valve to divert water through the collector(s) when the collector temperature is sufficiently greater than the pool temperature. When the collector temperature is similar to the pool temperature, filtered water simply bypasses the collector(s) and is returned to the pool.

Advantages of Solar Heaters

  • Inexpensive to operate: no additional monthly operating costs
  • Energy efficient: operate with your pool pump
  • Lifespan of 15 to 20 years
  • Environmentally friendly: use renewable energy source and emit no air pollution

Disadvantages of Solar Heaters

  • Expensive to purchase: many available for between $4,000 and $7,000
  • Dependent upon sun: cannot operate at night and operate less efficiently in cloudy weather
  • Heat pool water slowly
  • Unattractive installations on swimming pool owner’s roof or lawn

Solar Pool Heater System Types

Solar pool collectors are made out of different materials. The type you'll need depends on your climate and how you intend to use the collector. If you'll only be using your pool when temperatures are above freezing, then you'll probably only need an unglazed collector system.

Unglazed Solar Pool Heating Collectors

Because of their inexpensive parts and simple design, unglazed collectors are far less expensive than glazed collectors. Unglazed collectors don't include a glass covering (glazing). They are generally made of heavy-duty rubber or plastic treated with an ultraviolet (UV) light inhibitor to extend the life of the panels. These unglazed systems can even work for indoor pools in cold climates if the system is designed to drain back to the pool when not in use. Even if you have to shut the system down during cold weather, unglazed collectors are more cost effective than installing a more expensive glazed collector system.

Glazed Solar Pool and Water Heating Collectors

Glazed collector systems are generally made of copper tubing on an aluminum plate with an iron-tempered glass covering, which increases their cost. In colder weather, glazed collector systems—with heat exchangers and transfer fluids—capture solar heat more efficiently than unglazed systems. Therefore, they can be used year-round in many climates. Glazed collectors also can be used to heat domestic hot water year-round.

Both glazed and unglazed collector systems should include freeze protection if they'll be used in colder conditions.

Selecting a Solar Pool Heater

If you'll only be using your pool when temperatures are above freezing, then you'll probably only need unglazed collectors. They typically last longer than gas and heat pump pool heaters. Your actual cost and payback depend on many factors. Therefore, before you purchase and install a solar pool heating system, you should do the following:

  • Evaluate your site's solar resource
  • Determine the correct system size
  • Determine the system's efficiency
  • Compare system costs
  • Investigate local codes, covenants, and regulations


The proper installation of a solar pool heating system depends on many factors. These factors include solar resource, climate, local building code requirements, and safety issues. Therefore, it's best to have a qualified solar thermal systems contractor install your system.

After installation, properly maintaining your system will keep it running smoothly for 10–20 years. Consult your contractor and read your owner's manual for maintenance requirements. Your collector should require little maintenance if the pool's chemical balance and filtering system are checked regularly. Glazed collectors may need to be cleaned in dry climates where rainwater doesn't provide a natural rinse.

Solar Pool Heaters Benefits

  • Can extend swimming season for up to 12 months depending on
  • Average temperature rise up to 15-20º
  • Have no operating costs
  • No pollution, no fuel needed
  • Usually last 20+ years
  • Have a 10 Year warranty
  • Quick and easy installation
  • Minimal maintenance required

Other Solar Heating Products

Solar mats or blankets are also available. These are the least expensive, as there is no mechanical parts. The mat is composed of materials that readily absorb sunlight, and transfer the heat to the water below. These mats also serve as insulators, keeping heat generated during the day within the swimming pool at night.

Quick Facts

Quick Facts

  • A properly sized solar system will effectively raise temperatures well into the 80°F range. In addition to raising the water temperature
  • Swimming season can be extended in cooler climates by as much as 100 percent, and performs year round in warmer climates
  • There may be short periods during inclement weather when the pool water becomes cooler; however, a little sunny weather will return the pool back to a comfortable temperature.
  • Solar pool heating systems are best suited for recreational pools, but can be easily designed for commercial and industrial applications.

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