The Complete Guide to Solar Pool Covers

Unless you’re one of those, um, adventurous (not crazy, nope, not at all) polar bear people who likes jumping into ice-cold water, you probably want to keep your swimming pool heated. But before you run out and drop the dough on a traditional electric or gas heater, have you considered a solar pool cover?

A solar cover can raise the temperature of your inground or above ground pool, reduce your energy costs, minimize water loss, and in some cases, even decrease chemical needs. Surely, that’s worth a look.

What is a Solar Pool Cover?

You probably already have and use a safety pool cover. So why would you need another kind of cover? Because this one doesn’t just keep dirt and debris out of your pool—it actually heats the water.

Solar pool covers capture the energy of the sun and transfer it directly into your pool water to keep it warm. Depending on where you live, a solar pool cover may not keep the water as warm as an electric or gas heater, but the tradeoff is that it can actually save you money by reducing evaporation.

Heating Pool Water: Science!

A British Thermal Unit (BTU) is a measure of the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.

This is about the amount of energy released by just one lit match. Yes, one match could heat one pound of water! Well, if the water didn’t put the match out. We’ll have to figure that out later.

But right now, this means heating one pound of your pool water by one degree Fahrenheit only takes one BTU.

Let’s say you keep your pool at a balmy 80 degrees Fahrenheit. When one pound of your pool water evaporates, it doesn’t just take that one BTU with it. Oh, no. It actually takes a whopping 1,048 BTUs of heat out of your pool water.

Pool Without a Solar Cover

Now you have to replace both the lost water and the lost heat, which means evaporation not only robs your pool of heat and water, but also your wallet of money. But how much water can your pool really lose to evaporation?

Depending on where you live, it can be quite a bit. For example, the Arizona Department of Water Resources says in that region, a standard, uncovered pool can lose as much as four to six feet of water each year to evaporation alone.

Solar pool covers help you combat loss of heat and water in two ways.

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Solar Pool Covers Pull Double Duty

Now that we see how much energy and water are lost to evaporation, it’s easy to understand that the biggest factor in keeping your pool warm isn’t what kind of heater you use, or how high you keep the thermostat. It’s keeping water in your pool.

Every time you lose water—whether through splashing or evaporation—you have to replace it, and it takes energy to heat the newly added water. One of the best things about solar pool covers is that they pull double duty here.

First, they help your pool retain the heat already in the water by virtually eliminating evaporation. This is because solar pool covers are actual physical barriers that sit on top of the water, thereby preventing evaporation. Some solar pool covers perform this function better than others.

Pool With a Solar Cover

Second, a solar pool cover acts as a magnifying glass to amplify the sun’s warming effect. If you’ve ever held a magnifying glass between the sun and a sheet of paper, you can easily understand how that works.

But not every type of solar pool cover works the same way, or has the same effect, so the key is finding the right one for your pool and your lifestyle.

Solar Blanket

You may have seen one of these before. This is the solar pool cover that looks like bubble wrap. Just resist the urge to pop it! Solar blankets come in a wide variety of sizes and thicknesses. To find the correct size for your pool, measure the widest and longest parts of your pool.

Solar blankets are usually fairly inexpensive, but you can spend a little more for a higher-quality option. And don’t worry if you have a unique pool shape—you can trim a solar blanket to perfectly customize it to your pool.

Tucking Your Pool In: How to Use a Solar Blanket

The first time you unpack it, a solar blanket may be a little unwieldy, but it’s easily fixed. First, unfold it next to the pool. Spread it out bubble-side down on top of the pool water. The bubbles keep your cover afloat while acting as little magnifying glasses to heat up your pool.


Straight out of the box, the solar blanket will probably hang out over the sides of your pool, especially if you have a uniquely shaped pool. Use scissors to trim the excess so the blanket fits inside the pool.

Tip: Leave a flap 2 – 3 inches long where your skimmer is so you can tuck it under the edge of the skimmer. This allows you to push debris into the skimmer before removing the blanket.

Ideally, you’ll put your solar blanket on whenever the pool is not in use. Daytime is the best time for it to heat up your water, of course, since it relies on the sun. However, keeping it on through the night prevents water and heat loss via evaporation.

Tip: Running your pump while your solar blanket is on is completely safe.

If you’re in and out of the pool throughout the day, just be sure to put it back on when you’ve finished using the pool for the day. Obviously, you’re not going to want to swim with a solar blanket on the pool, so before you get in, you’ll need to remove it.

How to Remove a Solar Blanket

If you have a large pool, or if you swim often, removing the solar blanket every time you want to use your pool can be quite a chore. One solution is to cut the solar blanket into smaller panels so you can remove the pieces one at a time. If you’d rather not cut the blanket up, a convenient alternative is a solar cover reel.

Good for both inground and above ground pools, a solar cover reel is placed at one end of the pool. You’ll attach one end of the solar blanket to the reel, and then turn the handle or wheel. The blanket will be spooled onto the reel, saving you a lot of hard work.

Some solar blanket reels are available with wheels, so you can roll up your cover and then move the reel aside. Others come with mounting hardware to install permanently in one location. Which version works best for you will depend mostly on how much space you have around your pool.

If you don’t have a reel, you can pull the cover off and “accordion fold” it. Pull about four feet out, then fold that section in half. Continue pulling two-foot sections, folding each one back and forth like an accordion. This method also lets you rinse off each small section before folding, if needed.

Important: Always remove a solar blanket from the pool before allowing anyone to swim, especially small children and pets. Partially removing it or folding it back isn’t enough. It’s possible for them to become trapped under the blanket. It must be completely removed to avoid this risk.

Store Your Solar Blanket, But Not in the Linen Closet

At the end of pool season, it’ll be time to break out the safety cover, and store the solar blanket. But before you do that, you must make sure the solar blanket is clean and completely dry so you don’t get a nasty, moldy surprise when you open it up next season.

To clean your solar blanket, remove it from the pool, and lay it on a soft surface like grass. Concrete can damage the bubbles, making the blanket less able to float and do its job.

Once you have it spread out flat, use a soft push broom or soft scrub brush and clean water to scrub away dirt, algae or buildup, then rinse. Dry the blanket well by hand, using a leaf blower, or hanging it up to dry.

Tip: Don’t ever leave your solar cover out to dry on your lawn. It can burn your grass.

After you wash and dry your solar blanket, reel it up. Some pool cover reels come with a weather- and UV-resistant storage cover so you can store it outside if you don’t have any indoor space for it. If your reel didn’t come with a cover, you can always pick one up.

If you’re folding your blanket up, place it in a container with a sturdy lid to keep pests out. Then store the container somewhere cool and out of direct sunlight to prevent the cover from shrinking, and the plastic container from deteriorating.

Solar Blanket Benefits (Other Than Coziness)

In addition to warming your pool water, solar blankets offer some money-saving benefits.

Reduce Evaporation

A solar blanket cover can cut evaporation by about 95 percent.

Retain Heat

When the sun sets and the night air cools, a lot of the heat your pool gained during the day is lost. A solar blanket floating on the water keeps some of that heat from dissipating. And if you couple a gas or electric pool heater with a solar blanket, the heater won’t need to run as long to keep your pool temperature steady.

Keep Bugs and Debris Out

Although it’s not one of their primary purposes, solar blankets do shield your pool from bugs and debris such as leaves and twigs. If your blanket does trap debris, use a hand skimmer to scoop it out before removing the cover.

The more debris you can keep out of your pool water, the less you have to run your pump on high to vacuum, and the more you can save in energy costs.

Lower Chemical Costs

When water evaporates from your pool, you don’t just lose water—you also lose some of the chemicals you use to treat that water. By using a solar blanket, you can prevent 35 to 60 percent of your pool water chemicals from disappearing into thin air.

Imagine spending half as much money on chemicals every year. That savings alone would likely more than cover the cost of a solar blanket.

Blue Wave Rectangular Solar Blanket for Inground Pools - 16 ft. x 32 ft. Price: $124.99 Blue Wave Rectangular Solar Blanket for Inground Pools - 16 ft. x 32 ft. If you click this link and make a purchase, we earn a commission at no additional cost to you. Last Updated: 05/13/2019

Solar Rings (Not to be Confused with Solar Flares)

If a solar blanket seems like too much of a hassle to put on, take off, and store, you may prefer solar rings or squares. These can even be decorative because some of them have patterns and images such as palm trees printed on them, while others come in fun shapes such as flowers.

Solar rings are sold individually for around $25 – $35 each, or in sets for around $140 – $160 or more, depending on how many rings come in the set. The number you need to cover your pool’s surface will depend on the sizes of both your pool and the rings.

How to Use Solar Rings: They’re Not Just for Looks

Unlike the solar blanket’s air-filled bubbles, solar rings are flat and must be inflated before you place them on the water. You’ll inflate the inner portion only slightly, and the outer portion until it’s firm, the way you’d blow up a balloon. Then simply place them on the water and let them do their job.

Some rings have magnets around the circumference of the outer portion. This not only helps the rings stay connected to each other, thereby reducing gaps, it also keeps them from overlapping and leaving even more water exposed.

It’s important to note that neither rings nor squares will cover every inch of your pool water. There will be gaps, even when they’re connected by their magnets. It’s for this reason that solar rings and squares are not as effective as a solar blanket at either heating your pool water or preventing evaporation.

Tip: You can continue to run your pump while solar rings are on the pool.

How to Remove Solar Rings

This is where you’ll see an advantage over the solar blanket. Solar rings are extremely easy to remove from the pool, no reel required. It’s just a matter of detaching the magnets, scooping the rings from the water, and you’re done!

Store Solar Rings, But Not in a Jewelry Box

For temporary storage, such as when you’re swimming but you’ll be putting the rings back on the pool later, you can simply stack them near the pool. Keep them out of the wind, though, or they may end up all over the pool deck and yard.

Some rings and squares have loops on the outer portion so you can hang them up while you swim.

Long-term storage is easy, too. Once you have the rings out of the water, spray them off and, if necessary, use a soft push broom or brush to clear any debris from them. Do this before you deflate them to make sure nothing gets trapped in any folds or wrinkles.

Next, dry them completely. It will be easiest to do this by hand. Taking a leaf blower to solar rings may just blow them right back into the pool, or into the neighbor’s yard. While that might be entertaining, it won’t be efficient. (Actually, you’ll find a leaf blower can come in handy for a lot of pool-related cleaning tasks.)

Once they’re dry, deflate them, flatten them, and store them in their storage bag (if they came with one), or in a container with a lid. Keep the bag or container in a cool, dry place.

Regardless of how and where you store them, just be sure to keep them out of direct sunlight, and away from abrasive surfaces.

Solar Ring Benefits

In addition to having some of the same benefits as a solar blanket, and aside from being much easier to deploy and remove from the pool, solar rings and squares offer one major advantage over the blanket.

When they’re on the water, if a child or pet (or anyone) happens to fall into the water, solar rings will break apart on impact, and will not form a solid barrier that can make it difficult to come to the surface.

Reduce Evaporation

While they’re not as efficient as a solar blanket, they can still reduce pool water evaporation by about 50 percent, which can still save you money on water, chemicals, and heating.

Retain Heat

Even though they don’t cover the entire surface of the pool, they do still help the water retain some heat overnight as well.

Keep Bugs and Debris Out

Finally, they may catch some bugs and debris here and there, but probably not enough to make a noticeable difference in your cleaning time. Take care to scoop debris out of them before removing the solar rings from the pool so the debris doesn’t fall into the water during removal.

Again, less debris in the water can save pump and vacuuming time, which saves money.

Lower Chemical Costs

You may still see some reduced chemical use with solar rings But remember that once again, the savings won’t be as large as you might get with a solar blanket since the rings don’t completely cover the surface of the water.

Note: A solar cover option very similar to rings and squares is solar mats. They’re flat and do not require inflation. Most of them spring open and twist closed, just like a windshield sun shade. Their use, care, and benefits are pretty much identical to solar rings and squares.

Solar Rings - Pack of 6 Price: $168.96 Solar Rings - Pack of 6 If you click this link and make a purchase, we earn a commission at no additional cost to you. Last Updated: 05/15/2019

Liquid Solar Cover: The Future Is Now

Is it really possible that you could pour something into your pool water that magically warms it up? Yup. That’s basically how liquid solar cover works. Except it’s not magic; it’s more science!

Liquid solar cover contains aliphatic alcohols, which form a monolayer film on the surface of the water, thereby requiring upwardly escaping water molecules to expend energy in forcing adjacent molecular chains sufficiently apart to pass between them

In plain English? A one-molecule-thick layer of fatty alcohol sits on the surface of the water, inhibiting the water’s ability to evaporate normally. Preventing evaporation prevents heat loss, and voilà! Your pool stays warmer than if you had no solar cover at all.

Liquid solar cover ranges in price from about $10 to about $30 or more, depending on brand and whether you buy a single container or a pack of multiple containers.

How to Use Liquid Solar Cover

In addition to bottles, you can also find liquid solar cover in special dispersal packets, sometimes shaped like a cute little fish. Usually, you’ll just make a small cut in the dispersal packet, and set it free in the pool. Follow the instructions to be sure you add enough packets for your pool.

For bottled liquid solar cover If you click this link and make a purchase, we earn a commission at no additional cost to you. , simply measure out the appropriate amount according to the volume of your pool, and pour it in. That’s it. Really.

Don’t know your pool’s volume? Figure it out with this pool calculator:

Pool Volume Calculator Choose the shape of your pool first.
rectangle pool Rectangle
rectangle pool Round

We like to add enough liquid solar cover to last for a month, but always follow the manufacturer’s instructions for optimal performance. If you have a lot of splashout, heavy rain, or extremely dry conditions you may need to add liquid solar cover more often.

Tip: You can run your pump as usual with liquid solar cover in the pool.

You Can Remove Liquid Solar Cover, But Why?

Although we can’t think of any reason why you’d want to, the only way to remove liquid solar cover from your pool water would be to drain the pool and refill it, and no one wants to do that if it can be avoided.

The thing is, if you decided to stop using liquid solar cover for any reason, all you have to do is wait a while. The chemical naturally dissipates over a certain period of time, depending on how large your pool is and how much liquid solar cover you have to use.

For this reason, for as long as you want to use it, liquid solar cover must be added to your pool on a regular basis, so be sure to add it to your pool maintenance schedule.

Liquid Solar Cover Benefits

Just like any other chemical you add to your pool water, liquid solar cover is completely safe for people and pets. It won’t irritate your skin (although there may be exceptions in those who have extreme sensitivities), and it doesn’t leave any residue on you or your swimsuit.

Note: While it’s not a good idea for your pet to drink pool water on a regular basis, liquid solar cover is safe for the occasional sip or two your dog might decide to take when you’re not looking. Always check the safety notes for the brand you choose before using it, and before letting your pets into the pool.

Reduce Evaporation

You can cut evaporation by about 15 percent with liquid solar cover. Does it really work? Absolutely. We even tested it.

Retain Heat

Liquid solar covers are about 75 percent as effective as solar blankets at retaining heat. But remember, it works constantly without your having to remember to cover the pool at night.

This may be a tradeoff for never having to reel in, clean, and store liquid solar cover, though.

Keep Bugs and Debris Out

Well, here’s one area where solar blankets and rings are the clear winner. Of course, liquid solar cover isn’t going to keep bugs, leaves, and other debris out of your pool.

If you opt to use this heating method, you’ll have to stay on top of things with your handheld skimmer and vacuum.

Lower Chemical Costs

Nope, we’re actually adding a chemical cost with this one. But it’s (we think) an affordable one that offers a good return on that investment.

Heatsavr Liquid Pool Cover - 1 gal. - 4 Pack Price: $299.95 Heatsavr Liquid Pool Cover - 1 gal. - 4 Pack If you click this link and make a purchase, we earn a commission at no additional cost to you. Last Updated: 05/15/2019

Get More Bang for Your Buck

Now you know how each type of solar cover works, a few benefits of using them, and the best way to do so. But wait! There’s more! We’ve got a few extra tips to help you save even more money.

Are You Ready to Switch to a Solar Pool Cover?

While it won’t heat your pool as much as a traditional electric or gas heater will, any type of solar pool cover will keep more heat—and more water—in your pool.

But it doesn’t have to be a one or the other choice. You can use any kind of solar pool cover in tandem with an electric or gas heater, which will help you save money on utilities, water replacement, and pool chemicals. For such a modest upfront investment, you can’t afford not to have one.

Happy Swimming!

Frustrated by adding chemicals and trying to keep your pool clear all the time?

We cut out all the confusion of pool maintenance in this easy-to-read illustrated ebook and video course. It'll help you save $100 right away on pool care!

Click here to learn more
The Pool Care Handbook


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