Pool Care Pool Equipment

Solar Pool Cover on During the Day Bad or Good Idea?

There is no doubt solar covers are saviors. They help save on electric bills and prevent pool water evaporation. But there is one question bothering most pool owners – should I leave my solar pool cover on?

The correct answer is YES. But it will all depend on the season and the type of cover you have. In the cold season, leaving the solar cover helps preserve the heat. Solar rings and blankets are easy to withdraw compared to liquid solar covers. You have to assess the condition you have before deciding to or not leave your solar cover on.

Read along as I uncover more about when you should leave your pool cover on and when to take it down for storage. I’ll also answer some of the common questions you might be asking yourself about solar pool covers.

What is a Pool Solar Cover?

Even if you’re a newbie in a matters pool cover, you might have heard of the term solar pool cover. Right? It’s a familiar phrase, especially if you live in an area that experiences the cold season.

A solar pool cover is a swimming pool cover that allows sun rays to pass through into the pool water and trap it to warm the water and thus the name. Depending on how hot the sun is in your area, a solar pool cover can keep your pool water warm, similar to a pool heater. It does also help reduce the evaporation of water and pool chemicals.

When your pool stays open, the water absorbs substantial amounts of sunlight. The pool walls also absorb about 60% of the solar energy that enters the pool. With time this heat energy warms the swimming pool to about a degree Fahrenheit.

However, the heat gained is counteracted by the water evaporation causing the pool water to lose about 5° Fahrenheit for quarter-inch water lost. This is where the solar pool cover comes in.

Do Solar Pool Covers Really Work?

Of course. A 2014 Study done by Colgate University on using a pool cover showed over 30% of energy cost savings for the Lineberry pool on campus.

Another study done in 2016 by Cal Poly researchers on the effectiveness of various solar pool covers on evaporation showed reduced water loss when the pool covers were installed.

So, solar pool covers are proven saviors of heating billings and water chemical usage. Some even work like a magnifying glass by amplifying the sun warming effect to keep the pool water warm.

Should You Consider Leaving Your Solar Pool Cover On?

My answer is still yes. But there’re a few things you’ve to consider before you can decide to leave it on. They include:

Removal Difficulty

The installation and removal difficulty of a solar cover affects your decision to leave it on or remove it. There are three main types of pool covers: solar blanket, solar rings, and liquid solar cover.

All three have one thing in common; they are designed to help keep your pool warm and help you save on heating bills.

However, they have some differences in how you use them, installation and removability, and their practicality in reducing pool evaporation.

Solar blanket

A solar blanket is the toughest to install and remove. You need to lay a single blanket-like cover and then roll it out during removal. However, with the help of a pool cover reel, the withdrawal could be easier than the liquid solar cover.

If you’re using a solar blanket, you have to remove it every time you want to use it. You must also remove it when shocking your pool and when manually cleaning it. The challenge of removing it every time and then might force you not to leave it on.

Another thing, you cannot use it as a winter cover since it’s not strong enough to hold the ice and other debris that might settle on it.

Leaving it on and installing a winter cover on top won’t do you any good. So the best thing to do is to remove, clean, and store it away from sunlight.

You can leave it on the pool cover reel, but you’ve to find a dry shed that protects it from the damaging sunlight.

Solar ring cover

Solar ring covers are easy to install and remove. They come as small round covers, and you need multiple to cover your pool.

Because of their small round sizes, installing and removing them is easy. However, they’re not as effective as a solar blanket in keeping the water warm and preventing evaporation.

You have to take the solar rings off your swimming pool when you want to swim. But it’s not a must you remove them during manual pool cleaning.

However, if you’re shocking your pool, it’s a must you remove them. The harsh chlorine could cause damages.

Liquid solar cover

A liquid solar cover is quite different from the rest. As the name suggests, it’s a liquid substance (monomolecular film-forming liquid) that floats on the pool water. It’s not a popular type of solar cover since draining your swimming pool is the only way to remove it.

According to research, liquid solar cover can reduce evaporation by 85% but not the best in heat retention. It might be the toughest to remove, but it’s the easiest to handle.

For this kind of pool cover, there is no need to remove it. You can leave it on during cleaning, in the winter, and even when you’re swimming. I don’t see the need that could make you want to remove this type of solar cover.

But if there’s, you’ll have to drain and refill your pool, which can be pretty expensive, especially if you’re buying the water. You will also have to balance the pool chemicals, and that will incur additional costs.

So, if you have got the liquid solar cover, enjoy its services until it depletes in a week or two – it’s not too long.

Weather and Season

If you live in a hot area, the need for a pool cover is to reduce evaporation. Most pool owners that live in such regions cover their swimming pools to prevent water and chemical waste through evaporation. Most of them even don’t need the solar cover as it might overheat the pool water, causing other issues.

If you live in a place that experiences cold and warm weather, then having a solar pool cover can work to your advantage. You can use it to trap the sunlight during the day and reduce heat loss during the night. So, should you leave it on? Of course.

If your area experiences extreme winter, there is no need to leave the cover on. Even if it’s a solar blanket, you’ll still need a much safe cover on top of it. That would mean the blanket isn’t helping in any way since the sunlight isn’t even reaching it. The best move would be to remove it and keep it safe.

But if your area receives partial cold season, you can leave it on and use it to prevent pool freezing. When there is sunlight, you can take off the winter safety cover and leave the solar blanket to do the heat-trapping.

Why Should You Consider Leaving Your Solar Pool Cover On?

Apart from keeping your pool water warm, solar covers offer some real money-saving benefits that you might want to enjoy when you can.

Heat Transfer

Most solar covers come with a design that allows sunlight to penetrate the pool water and trap it in. Some come with a different design that will enable them to magnify the sunlight.

When they magnify the light, they can heat more water and trap the heat inside. With time, the water becomes warm and swimmable – you might not need a pool heater.

The type of solar pool cover that achieves this is a bubbled clear solar blanket. The clear top allows enough sunlight to pass through while the bubbles magnify the energy.

You could also come across a colored, opaque solar blanket that works the same way. However, there isn’t much solar passing through, and instead of retaining heat, it acts as an excellent heat transfer cover.

Some of these solar blankets come with a clear top and a dark bottom but are still bubbled. The clear top allows the sunlight to penetrate, but the dark base absorbs it and transfers it to the other parts of the pool. Heat retention for such a cover isn’t that good, though.

Remember, solar rays are enemy number one for chlorine. It might be beneficial for you to use a solar cover, but keep in mind that the same solar you enjoy can affect chlorine levels in your pool and leave your pool unprotected.

The best solution here is to use stabilized chlorine as your sanitizer or add some cyanuric acid to your pool water for protecting the sanitizer.

Save on Heating Bills

After sunset, the cold night comes in, and a lot of heat collected during the day might get lost. Even though the solar blanket can trap the heat inside, some might still dissipate.

That’s why it’s good to heat the water at night too. If you were to run a pool heater (gas or electric) while the solar blanket is still on, you could save yourself some real money.

The pool heater won’t need to run that long to keep the pool temperatures steady.

Reduce Evaporation

Several renowned research groups have proven that solar pool cover can reduce evaporation by about 95 percent depending on the type, with the solar blanket being the best.

Solar rings cover partial sections of the water surface compared to the solar blanket covering the entire thing.

The liquid solar cover might also cover the entire pool, but its evaporation protection is compromised a bit but still useful when there are strong winds.

Protects Against Bugs and Debris

Yes, solar blankets are excellent in heating pool water, but they are also impressive in shielding it from bugs and debris.

It can help reduce the time you take skimming the debris out, how often you vacuum it, and more. In the long run, it will save you more than just energy bills.

However, don’t forget the solar blanket isn’t the same as a standard pool cover. So don’t allow too much debris to settle on it before you can remove them.

Reduced Chemical Costs

During evaporation, your pool water goes flying as moisture. The sad news is that the water doesn’t go alone; it carries some pool chemicals.

When you install a solar cover, you reduce the evaporation while at the same time you lower the chemical loss. You can save up to 60% of water chemicals lost through evaporation.

Imagine how much you spend on water chemicals. When there is evaporation, the chemical expenses might double or even triple.

A solar cover would save you from all these extra expenses and much more.

Should you Leave Your Pool Cover On Or Off During the Day?

It all depends on the type of cover you have, the weather, and your plans for the day.

If you have a solar blanket or solar rings and want to enjoy a swim or a pool party during the day, you will have to take it off.

However, if you want to enjoy the same events during the night, leaving it on during the day would allow the sunlight to warm the water. And when the time to swim comes, you’ll be enjoying some warm bath on a cold night.

If it’s a scorching day and you’re thinking of how to cool down your swimming pool, leaving the solar pool cover on won’t be the best move. The solar cover will heat the water more, which won’t help you achieve your pool-cooling goal.

Does a Pool Heat up Faster with the Solar Cover On?

Of course. A solar pool cover acts as a heat cover that holds that heat inside the pool water, especially for the solar blanket.

When you run your pool heat in an open pool, some heat will be lost. But when you heat it with the solar cover installed, it will blanket all the heat inside the pool.

With time, the heat transfer will occur, and all your pool will reach the ideal temperature sooner. So, yes – the pool heats up faster with a solar cover on.

How Fast Does a Solar Cover Heat a Pool?

Like solar panels, a solar cover’s effectiveness depends on its size, type, and amount of hours of direct sunlight the swimming pool receives each day.

A standard-sized solar blanket can raise standard pool temperatures by 5 degrees in 12 hours. But to achieve this, the swimming pool has to stay adequately covered and get no less than 6-hours of direct sunlight in a day.

Can You Run Pool Pump with Solar Cover On

Yes. A solar cover does not affect pool pump performance. Instead, it can help with heat transfer to all the corners. However, during circulation, some heat might be lost, but that is normal. Another thing, if you’re using a solar blanket, the pool pump efficiency might drop a bit because of the reduced surface area.

Final Verdict!

Should I leave solar cover on? Yes. But if you’re shocking your pool, removing it would help protect it from harsh chemicals. Another thing, if you live in an area that experiences scorching days, you might want to remove it to allow the swimming pool to cool. You might not even need it at all. If you decide to leave it on, keep checking the water temperatures to ensure they are not too high. If you choose to take off, proper storage away from direct sunlight would be the best move.

About the author

Sharif Miah

Hi! I'm Sharif, the founder of Globo Pool® and I have been working in the pool & hot tub industry for the last few years. I love to share my experiences with people & hope you are enjoying my information and lessons!

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