Swimming Pool Energy Efficiency

Beginner

Inside this Article

Shading your pool to prevent overheating
In hot climates, shading your pool to prevent overheating from solar gain can be an effective passive strategy.
Siting the pool to receive as much sunshine as possible
In cooler climates, siting the pool to receive as much sunshine as possible will help maintain a more comfortable water temperature.
Above-ground pools may incur more heat loss
In cooler climates, above-ground pools may incur more heat loss through the pool walls compared to their in-ground counterparts.
Opaque pool cover
Opaque covers reduce heat loss and algae growth, but can reduce or eliminate solar heat gain.
Translucent solar pool cover
Translucent solar pool covers have bubble insulation to reduce heat loss, but can still admit solar gain.
Solar rings
Solar rings are touted as being easier to handle than a blanket cover, but can leave 25% to 30% of the pool’s surface uncovered.
Liquid pool cover
Liquid pool covers provide a very thin layer of solution that floats on the water’s surface to reduce evaporation.
Variable-speed pump
Variable-speed pumps are very energy-efficient and have built-in controllers for ease of function.
Shading your pool to prevent overheating
Siting the pool to receive as much sunshine as possible
Above-ground pools may incur more heat loss
Opaque pool cover
Translucent solar pool cover
Solar rings
Liquid pool cover
Variable-speed pump

Energy-efficiency strategies and proper siting can increase the effectiveness of solar pool heating systems or sometimes make them unnecessary.

Solar pool heating (SPH) is cost-effective for extending the swimming season and increasing comfort in outdoor swimming pools. But, as with any heating system, addressing energy losses first will maximize the system’s efficacy and performance, and provide additional savings.

Siting

Pools themselves are solar collectors. According to NREL’s Conserving Energy and Heating Your Swimming Pool with Solar Energy, between 75% and 85% of the sun’s energy that strikes a pool’s surface is converted to heat energy. Many seasonal pool owners capitalize on this and use their pools without supplemental heat. In hot climates, pools may need shade to prevent overheating.

The best opportunity to reduce a pool’s energy use is proper siting. The pool should be placed in an area that maximizes the solar gain when it is most needed. In climates with a short swimming season, such as those in northern areas, it is best for the pool to receive unimpeded sunlight from 8 a.m. to 4 p.m. during summer. In hot climates, it can work out best to site for maximum passive gain during the spring and fall, when the pool’s heat loss is more significant.

Shading assessment tools can be used to find the best pool siting. Tools like the Solar Pathfinder ($259) or SunEye (starting at $1,995) can assist with this task. A smartphone application that costs $20 to $40 (such as Comoving Magnetics Solar Shading application for Android and Solmetric’s iPV application for iPhone) can provide sufficient information for pool siting. 

Pools are often sited for aesthetics and accessibility, which may limit opportunities for energy efficiency. While an aboveground pool could be relocated if there is a more appropriate location, in-ground pools do not have such luxury. Instead, tree removal may be the only option for increasing an existing in-ground pool’s passive solar gain.

Modes of Heat Transfer

Heat can flow into and out of a pool through conduction, evaporation, convection, and radiation. If there is a difference in temperature between the pool water and the earth (for an in-ground pool) or the air (for an aboveground pool), heat will flow through the pool walls. As pool water evaporates, heat is lost from the pool. Additionally, wind blowing across the pool’s surface can extract heat through convection and the surface of the pool will radiate heat to a colder sky.

Climate has a significant impact on a pool’s heat loss. For example, evaporation is more pronounced in dry climates. Areas with clear, cold nights will experience increased radiation from the pool surface. At higher latitudes, the earth’s cooler temperature will lead to greater heat loss through the walls of an in-ground pool.

Conduction through pool walls. In typical situations, the desired pool temperature ranges from 78°F to 82°F. Therapy pools are warmer, between 92°F and 94°F. Since there is often a temperature difference between the pool water and the surrounding earth or air, heat is transferred through the pool walls.

Comments (0)

Advertisement

X
You may login with either your assigned username or your e-mail address.
The password field is case sensitive.
Loading