How Do Solar Pool Covers Work?

blue solar pool cover

If you want to extend the swimming season, having a pool heater is the way to go. Most pool owners use swimming pool covers to keep out debris and reduce evaporation. Solar pool covers not only cover the pool but also naturally heat it with solar energy, saving you money on your energy bills. So, how do solar pool covers work?

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What is a Solar Pool Cover?

Solar pool cover in a carton box
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Solar pool covers are large sheets of plastic resembling bubble wrap that float on top of your swimming pool. They naturally heat your pool with solar energy, keeping the temperature comfortable throughout cooler months. Solar pool covers come in many colors, sizes, and thicknesses.

How Does a Solar Pool Cover Work?

Swimming pools lose 75% of their heat due to evaporation, so a solar cover acts as a barrier between the water and the air. It effectively heats the pool by allowing more sunlight to enter the pool while its air bubbles trap the heat. As their main job is to maintain heat by preventing evaporation, solar pool covers work best with other sources like electric or gas heaters.

Solar pool covers can raise the temperature of the pool by an average of 10 to 15 degrees Fahrenheit. Thinner solar covers allow more heat to pass through to the water, but thicker covers absorb more heat and are more durable against UV rays and chemicals.

To keep the solar pool cover working efficiently, you should keep the cover on as much as possible between swims. You can make it easy to roll the pool cover on and off by attaching a metal reel to one end of the pool deck, but you can also let it float freely on the surface.

Types of Solar Pool Covers

Solar Blankets

Solar blankets, also called bubble solar covers, help capture and retain heat with small thermal bubbles. Depending on the amount and intensity of sunlight, solar blankets can increase the pool water temperature by up to 15 degrees Fahrenheit.

You can purchase a solar blanket larger than your pool’s surface area and fit it to your pool shape by unfolding and placing the blanket over the water and trimming the edges to fit.

Custom Solar Pool Covers

For homeowners who have uniquely shaped swimming pools, custom pool covers are more expensive premium solar blankets designed to fit nontraditional pools. They can include a reel to retract the cover and can double as a security cover.

Solar Rings

Solar rings are circular floating discs with a lining of solar bubbles. They are smaller and less bulky than solar blankets, which leaves some water exposed. Solar rings are available in different shapes and sizes, so they can be mixed and matched to cover the surface of your pool. They’re a little less efficient than solar blankets, as they only reduce heating cost by 10%-15% while solar blankets reduce costs by 17%-20%.

Liquid Solar Pool Covers

Liquid solar pool covers can help increase the water temperature, but they are not traditional covers. It’s a biodegradable liquid in a bottle that is poured into the water based on the dose recommended for the pool size. The liquid will need to be replenished every other month, and it will only heat your pool by about 6 degrees. It’s also not effective at stopping leaves and debris from getting into the pool water because it isn’t a true cover.

Solar Covers with Safety Features

If you are looking to heat your pool but also provide a level of protection, there are a few types of solar pool covers that have the safety of children, pets, and local wildlife in mind. These solar pool covers are durable enough to hold the weight of four people, which exceeds the American Society for Testing and Materials standard of a pool safety barrier. These types of solar covers are designed so that if someone were to fall onto one, it would be like falling onto a waterbed.

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What Type of Pool Can You Heat with a Solar Cover?

Pool covered for winter protection
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Solar covers are most effective on pools with plenty of sun exposure and in regions of the country that have a warm, sunny climate most of the year. They are compatible with any type of outdoor pool, whether it’s an in-ground or an above-ground pool. Obviously, solar pool covers are an ineffective heating method for indoor pools due to a lack of direct sunlight. 

Pros of Solar Pool Covers

On top of raising pool temperatures by an average of 10 to 15 degrees, solar pool covers come with other added benefits:

Reduces Pool Heating Costs

According to the U.S. Department of Energy, solar pool covers reduce pool heating by 50% to 70%. They minimize heat loss by trapping the heat from the sun during the day. As a result, you don’t need to use an electric or gas pool heat pump as often, saving money by decreasing energy costs.

Reduces Maintenance

Solar pool covers make pool maintenance much easier by protecting the pool from leaves, bugs, twigs, and other debris that ends up in the water. As a result, the water can stay clean and will require less skimming and vacuuming, which means less time cleaning.

Reduces Evaporation

Since solar pool covers reduce evaporation, they keep your water line from sinking so that you have to refill your pool. Not having to refill your pool will save on your water bill. Also, since solar pool covers reduce evaporation, they keep your pool’s chemical level and composition, thus eliminating the need to add more chemicals that are typically lost due to evaporation.

Environmentally Friendly

Electric and gas pollute the environment and increase the greenhouse effect. Solar pool covers use sunlight, which is a renewable source of energy, making them a great environmentally friendly option for homeowners who want to reduce their carbon footprint.

Cons of Solar Pool Covers

There are a few drawbacks to solar pool covers to consider. Going solar isn’t right for everyone.

Cost

A high-quality solar cover can be pricey, especially if you have a large pool or choose an automatic or semi-automatic cover that unrolls. Custom solar covers are the most expensive and will not fit everyone’s budget.

Won’t Fit All Pools

If you have a very large or uniquely-shaped swimming pool, you will need a custom-sized solar cover, which will cost more than a standard cover. While solar covers come in a wide variety of sizes, a standard solar cover may not be large enough to accommodate a lagoon-style pool or other specialty designs.

Does Not Provide Pool Safety

Solar pool covers do not offer the security that a pool fence or pool safety net does and should not be used as a substitute for either. Pool owners with pets or small children will need to invest in a custom solar pool cover that offers security features.

Not as Durable as Standard Covers

Solar pool covers are not as durable as other pool covers. A standard mesh security cover has a 10- to 15-year lifespan, while the warranty for higher-end solar pool covers is 3-7 years.

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Cost of Solar Pool Covers

Close-up of part of pool covered with blue solar pool cover
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A solar pool cover doesn’t offer as much control over the pool temperature as a solar pool heater. However, If you are on a budget and still want to extend your swimming season, here is what you can expect to pay for a solar pool cover.

  • High-End Solar Pool Covers: Custom solar pool covers can cost up to $1,000 if you install a pool reel. The best ones will last 3-7 years.
  • Average Solar Pool Cover: Solar blankets and solar rings, which last a few years, cost an average of $200 if installation is DIY and you do not install a reel.
  • Low-End Solar Pool Covers: Liquid solar covers cost less than $40 per bottle (32 fluid ounces) and are only needed every other month, making the expense approximately $20 a month. About 4 fluid ounces of liquid solar covers will effectively cover 20,000 gallons of water.

FAQ About Solar Pool Covers

Should you leave a solar cover on the pool all the time?

During the swimming season, you should have a solar cover on the pool whenever the pool is not being used. If you are not going to be using the pool in the colder months, you should close the pool with a winter cover.

Can you leave a chlorine floater in a pool with a solar cover?

No, it isn’t recommended. A floating chlorine dispenser under the cover will simply sit in place, causing a large concentration of chlorine in a single area. This will cause bleach spots, damaging your solar pool cover and the pool finish.

Do solar covers cause algae?

Solar pool covers will warm your water, which can accelerate algae growth in the right conditions. You will want to consider getting the correct water chemistry balance in your pool before placing the cover on top.

When to Hire a Pro

Never thought you could heat your pool and extend your swimming season while at the same time lowering your energy bill? Solar pool covers do just that. It’s a win-win-win.

If you’re ready to reduce your solar pool heating costs and your carbon footprint, PoolGnome can connect you with a local solar pool heater installation expert to learn about your options.

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Lydian Pine

Lydian Pine is a creative writer and studio artist whose work first debuted in a short story anthology. She graduated from the University of North Texas in 2020 and enjoys video games, theatre, and swimming. Lately, she has started to study entomology as a hobby.