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Top-rated solar pool covers to regulate water temperature

Experts explain how to choose a solar pool cover to keep your pool’s water warm and its chemistry in check.
Solar pool covers heat the water and prevent evaporation, keeping the water warm and chemically balanced.
Solar pool covers heat the water and prevent evaporation, keeping the water warm and chemically balanced.Jarin13 / Getty Images ; AleksandarNakic / Getty Images ; Amazon

During the dog days of summer, taking a dip in the pool can provide sweet relief from the sweltering heat. But pools need routine maintenance to ensure their chemistry is in check and the water safe, and pleasant to swim in. A solar pool cover can help with that. In addition to keeping leaves and other debris out of the water, solar pool covers are designed to help regulate water temperature, keeping the water warm as temperatures drop at night or later in the summer season. They could also save you money on your utility bills and on chemicals too, since they reduce the amount of heat and chlorine lost when you’re not using your pool. We spoke with swimming pool experts about how solar pool covers work and how to pick the right one. With their guidance, we rounded up a few options based on high ratings from shoppers.

SKIP AHEAD Highly rated solar pool covers | How do solar pool covers work?

What to look for in a solar pool cover

Size, thickness and color are the most significant factors in choosing a solar pool cover.

Pool covers need to cover the pool exactly from edge to edge. Large, high-quality solar pool covers close to 800 square feet may cost in excess of $200, whereas a smaller cover closer to 100 square feet will be closer to $100 or lower. If your pool cover is slightly larger than your pool, you can usually cut it to size without voiding the cover’s warranty.

Thicker pool covers (14 to 16 mils) should offer better insulation in colder, windier climates, said Gilda Dobrica, founder of ProSwim NYC and creator of the Teach-Your-Child-To-Swim e-course. Thin pool covers — around 8 to 10 mils — can save you about $100, broadly speaking, and may be sufficient in warmer climates. Solar pool covers with thickness between 10 to 12 mils fall in the medium range.

Blue solar pool covers are best. “A UV-protected, translucent blue color offers a better balance between heat retention and pool chemical protection,” Dobrica told us. Dobrica said that a clear cover will warm the pool water the most, but it will also allow more UV rays, which can make chlorine less effective as a disinfectant. A chemically imbalanced pool without enough chlorine could lead to algae blooms in your pool.

Highly rated solar pool covers

We rounded up the following solar pool covers using the above expert guidance and high shopper ratings.

In The Swim 12-Mil Solar Pool Cover

This translucent blue solar pool cover from In The Swim and comes in both rectangular and round shapes and a variety of sizes. After five to seven days of sunlight, the cover can increase the temperature of the water by 8 to 10 degrees Fahrenheit, according to the brand. It has an average rating of 4.3 stars from over 3,000 reviews on Amazon.

Blue Wave 8-Mil Solar Blanket

This 8-mil round blue solar pool cover can increase your water’s temperature by up to 15 degrees Fahrenheit, according to Blue Wave. The brand says that the cover is resistant to damage from UV rays and can reduce water and chemical evaporation from your pool by up to 95%. The cover comes in 12-, 18-, 21-, 24- and 30-foot sizes and has a 3-year manufacturer's warranty. It has a 4.3-star average rating from over 2,600 reviews on Amazon.

Doheny's Clear-Tek Micro-Bubble Solar Cover

This cover comes in both translucent blue and clear and can be cut to the size of your pool without voiding the warranty. The brand says this cover reduces enough evaporation to cut water heating costs by 70%. It also has a 4.3-star average rating from over 610 reviews on Amazon.

BigXwell Solar Pool Cover

This blue solar pool cover comes in three different sizes: a rectangular 16-mil 6-foot by 12-foot, a rectangular 16-mil 12-foot by 24-foot and a round 8-mil 12-foot. The thousands of bubbles work to reduce pool water evaporation by up to 95%, while also maintaining the chemical composition of the pool, according to the brand. The cover has a 4.5-star average rating from 150 reviews on Amazon.

How do solar pool covers work?

A solar pool cover essentially absorbs energy from the sun to heat pool water, concurrently helping maintain its heat and regulating the chemical balance of the water by preventing evaporation.

Heating

Solar pool covers have two sides: a flat side and a side with air bubbles, which you place face down in the pool water. When sunlight hits the flat side of the blanket, it warms the air in the bubbles, which in turn heats up the water. In addition to heating the pool, Dobrica said, the air bubbles on solar pool covers also serve as insulation, preventing more heat from escaping the pool water as the weather cools later in the summer season.

Evaporation

Solar pool covers can help reduce evaporation from your pool, which consequently slows down its heat loss and helps keep important chemicals in the water. Since the atmosphere is almost infinitesimally cold, heat from ground level soil and water will radiate to the atmosphere, especially if it’s colder, later in the day and when skies are clear, said Stephen Carr, a professor emeritus of materials science and engineering at Northwestern University. Carr said that a pool “could have easily lost 5 degrees Fahrenheit worth of temperature just due to radiation at night.”

Chlorine in pools is “volatile” and will release into the air from the water, Carr said. He explained that this is why your eyes may hurt when swimming in an indoor pool — what you’re feeling is the chlorine gas that’s evaporated from the pool. Reducing the evaporation can keep those necessary chemicals in the water, saving you money on both heating and chlorine costs.

CORRECTION (Oct. 18, 2021, 7 p.m. ET): A previous version of this article misstated the unit of length used to measure the thickness of solar pool covers. They are measured in mils, not millimeters.

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