How Much Does a Solar Cover Heat a Pool?

What is a Solar Cover?

A solar cover, or solar blanket as they are often referred to, is an inexpensive way to help heat your swimming pool water. It floats on the surface of the water and draws in the sun’s UV rays. They are made of plastic and kind of look like the bubble wrap you would find in a package. They come in many sizes and thicknesses. Usually they are blue, clear or silver. They not only keep heat from escaping, but draw additional heat from the sun.

How Much Heat?

Whenever I sell a customer a new heater, they usually go home with a solar cover as well. This is because the majority of the heat from your pool’s water escapes from the surface. Some is absorbed into the surface as well. Think of a cup of coffee. The cup gets warm, meaning it is absorbing heat. You will also see steam coming from the top of your cup as the heat burns off.
On average, a fully covered swimming pool could increase your swimming pool water’s temperature by 10-15 degrees. This is, of course, presuming that the days have been sunny. Usually we need three consecutive days of sunshine to get the full effect from our solar covers.

How Fast Will it Heat My Pool?

Again, relying on the weather to be sunny, you may notice an increase in temperature in as little as 6 hours. This will be expedited if paired with a swimming pool heater. You already spent a ton of money on your pool heater. It is not cheap to operate. So, why not protect that heat with an easy to use solar cover.

Sizing Your Solar Cover

I often get asked if one should cover their entire pool. The answer is, to get the fullest payout from your solar cover, yes. However, a completely covered swimming pool is going to be the warmest. What likes, nice, warm water? You guessed it. Algae. This will only be a problem if you have other problems. What I mean by this is you have other algae-causing factors. These can include poor water chemistry, including high phosphates. Poor circulation such as not running your swimming pool pump long enough can be a factor. Having a dirty filter also interferes with circulation. These in and of themselves can cause algae. Throw on a solar cover, you are exacerbating the problem. If water chemistry is not your strong suit, you may want to consider covering 80-90% of your pool.
Solar covers come in standard sizes whether oval, round or rectangular. Go one size bigger when purchasing a cover. This allows you to cut it down to size and shape. There is usually no need to weigh down the edges of your solar cover because the material is pretty good at sticking to the water’s surface.

 

Cutting Your Solar Cover

This will not void your warranty. The warranty covers the laminated seals that make up your cover from separating. It does not cover the bubbles falling off. When this happens it is usually due to poor water chemistry or improper storage. Some people choose to cut their cover into manageable strips. This is especially true in large pools. Dragging a gigantic cover off and on can be arduous. If you plan on leaving it in one piece, you may want to consider a solar reel.
Solar reels sit at the base of your swimming pool and connect to the solar blanket. When you want to remove it, you crank the lever and roll up the cover like putting toilet paper back on the roll. These are not cheap and many consider them an eyesore.
Before you cut your cover, figure out the square footage of your pool at the longest and widest parts. You probably have already done this when you were deciding on a size. Lay the cover flat for a day or so so that it takes on its true shape. Then, bust out any household scissor and snip away!

Dirt and Debris

Another advantage to having a solar cover is they help keep dirt and debris from falling into the swimming pool. You would need to carefully remove the cover or else it will all fall in. People in places that do not winterize their swimming pools with a solid cover, often turn to solar covers. They just leave it on all winter. They still maintain the water chemistry and circulation.
You can absolutely leave your automatic pool cleaner attached when covering your swimming pool. It is advisable to keep the water as clean as possible. As far as a chlorine floater, you can leave this in if you wish, but bear in mind it could get trapped and the excess secretion of chlorine in one spot could damage your cover and even you swimming pool’s surface. We suggest to our customer’s to remove the floater in the winter regardless of a cover to help cyanuric acid levels to remain in range. See you poolside!