How Fast Does a Solar Cover Heat a Pool?

Written by Michael Dean
November 30, 2023

sun shining on a solar pool cover and stopwatch

One of the most obvious ways to extend your pool season is to heat the pool. Although pool heaters come in all shapes and sizes, a solar cover is another more affordable and environmentally friendly option to heat your swimming pool. Solar covers help heat a swimming pool naturally by absorbing the sun’s heat and transmitting it to the water. It also helps by trapping the heat underneath the solar cover so that it doesn’t escape during the cool of the night.

If you are contemplating getting a solar pool cover and want to learn more about it, read on. In this article, I will help answer some common questions about solar covers, including how fast solar covers heat pools.

Main Takeaways

  • The effectiveness of a solar pool cover depends on the type of solar pool cover, weather conditions, and surface coverage.
  • Solar blankets are by far the most effective type of pool cover, both in terms of heating and evaporation prevention.
  • Solar pool covers can heat up a pool up to 15 degrees Fahrenheit in the right conditions.
  • Although solar covers can certainly heat pools, they do not work well as replacements for heaters.

How Fast Does a Solar Pool Cover Heat Your Pool Water?

On average, you can expect a solar pool cover to heat your pool by up to 5 degrees in 12 hours. But with that said, how fast a solar pool cover will heat your pool depends on various factors, including what type of solar cover you have and weather conditions.

It is important to note that solar pool covers work best alongside another heat source, as the solar pool cover’s main job is to maintain heat by preventing evaporation. On its own, it won’t be as effective, if at all. To better understand how fast a solar cover works, I will detail factors determining how quickly these solar covers heat pools.

Type of Solar Pool Covers

There are three types of solar pool covers: solar blankets, solar rings, and liquid solar covers. Although all three types are effective, the degree of effectiveness differs.

Solar Blankets

Also called bubble solar covers, solar blankets work well to heat your pool and cover the entire surface area. Among the three types of solar covers, solar blankets are the most effective at heating a pool, but the issue is that they are a lot more cumbersome to deal with.

Solar blankets rely on the sun to heat the pool. For a pool completely covered by a solar blanket, expect the temperature to rise anywhere between 5 and 15 degrees in a single day. Make sure you find the right way to face your solar blanket, so you effectively transfer the heat from the sun to the water.

Solar Rings

Although solar rings are easier to install as they are smaller pieces of equipment, there is an added drawback of uncovered pool areas, which makes them effective but less efficient than solar blankets. Depending on how much sun your pool gets, solar rings can heat your pool by up to an additional 2 to 5 degrees after a couple of days.

Liquid Solar Covers

Liquid solar covers are a modern invention that are the easiest to deal with among the three solar cover choices. You simply need to pour the liquid into the pool, creating an invisible and non-toxic barrier that stops heat from escaping the pool. Unlike solar blankets and solar rings, liquid solar covers cannot help heat the pool but will instead work to keep the pool warm.

However, these are an excellent alternative for those looking for an easy solution to stop the heat from evaporating the pool water. There’s also the plus of not dealing with a physical cover you need to place and remove. You can even swim in the pool with the liquid inside.

Weather Conditions

The weather will also play a big part in the effectiveness of a solar pool cover. As mentioned, solar covers do not work alone; they should not be used as a primary source to heat your pool. They require another heating source to work more effectively: the sun or a pool heater.

If you rely on the sun to heat your pool, it makes sense that the more sun your swimming pool is exposed to, the faster it will heat up. For example, a pool entirely covered by a solar blanket and gets at least 6 hours of direct sunlight may heat 5 to 15 degrees in a single day.

Alternatively, even if you use a pool cover for one week straight under cloudy skies, there’s a high chance that your pool may have heated up just a couple of degrees despite constant use.

Another thing to keep in mind is the night temperature. Most water evaporation happens in the cool of the night, so the cooler the night is, the less effective the solar pool cover will be at reducing heat loss.

Surface Coverage

Part of the reason a solar blanket is more effective than a solar ring or a liquid solar cover is due to the amount of surface coverage. The more the solar cover covers, the better it will be at heating and heat retention. Even if you couple your solar cover with a pool heater, your pool will only lose precious heat from heat-robbing winds and cool air temperatures if it is not effectively covered.

How Much Warmer Can a Solar Cover Make Your Pool?

Depending on the weather, a solar blanket can heat a pool even up to 10-15 degrees Fahrenheit in a single day. However, on cool, cloudy days, a solar cover will not be as effective at warming up the pool. On average, expect about a 5-degree increase within the first day.

Of course, how much warmer it can make your pool depends on several factors. Most notably, I must reiterate that not all solar pool covers can heat a pool. Liquid solar covers are ineffective at heating pools and are instead used for heat retention. On the other hand, a solar blanket is the most effective solar cover type for heating a swimming pool, as you can see above.

For more information on use cases, read my article on how to use every type of solar pool cover.

Can a Solar Cover Be a Replacement For a Solar Pool Heater?

Generally, no. If you plan to use a solar cover as a replacement for a solar heater, keep in mind that it won’t be as effective, as solar pool covers are not meant to be used as heaters. Although they can certainly be used to heat the pool, their primary role is to prevent heat from escaping via evaporation. But with that said, if you live in a warmer state, you may not need to purchase an expensive solar pool heater, so using a solar cover could be a great money-saving option.

Solar covers are generally used alongside a heating system like a solar pool heater. However, solar pool heaters can get quite pricey. So, if you are looking for an environmentally and budget-friendly option to heat up your pool effectively, only having a solar cover could be a potential option in the right circumstances.

(Solar) Cover Your Pool!

Solar covers may not be a replacement for a pool heater altogether, but they are a great addition to any pool heating system. It can do a lot to keep your pool warm by preventing evaporation. Plus, if you have a solar blanket, you may even be able to raise the pool water temperature by a few degrees on a sunny day!

Are you tempted to get a solar cover for your pool? For recommendations on which one to get, head over to my top picks for the best solar pool covers. And make sure to keep your solar covers clean!

Do you have any more questions about solar covers or heating your pool? Drop me a line.

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