We earn commissions from purchases

Solar Cover Bubbles: Up Or Down?

Pool covers have two distinct textures, a bubbled-side and a smoother-side. Some people accidentally put the wrong side down and don’t heat their pool properly! Installation for a pool cover is basically just “what side goes up?” Let’s get that one part right!

Pool Cover Bubbles Up or Down?

You should put the bubbles down. The bubbles need to face the water and the smoother side faces up. Solar covers work by trapping heat that would otherwise be lost. The pockets of air created between the cover and the surface of the water heat up, trapping heated air next to the water to keep your pool warm.

The solar pool cover first absorbs sunlight, heating up the air bubbles on the surface of the cover. The heat from the bubbles heats the pool water, raising it by anywhere from 10-15 degrees (Fahrenheit). That temperature increase is enough to extend your swim season by a few weeks to a full month!

Detailed Answer

The bubbles cause the cover to float above the water, while still transferring heat. So bubbles go down into the water when installing.

Do Solar Pool Covers Work A Concise Guide

There isn’t much to “installing” a pool cover, but you may need to cut it to fit the shape of your pool, to maximize effectiveness. Usually, markers and scissors are enough to trim down the solar cover.

Since the pool cover heats your pool mainly by trapping heat, you’ll want to cut the cover around the edges fairly tightly to keep it flush with pool walls. You don’t want heat escaping through cracks at the sides, but you also don’t want the cover to have wrinkles that lose heat because it doesn’t fit properly.

Pool covers not only prevent heat loss during the day, but they prevent the cold night air from sucking away that valuable swim heat as well. I love the feeling of taking the tarp off at midnight and climbing into a pool that’s still warm from the day, while the night air is crisp!

Reducing Evaporation

Does pool water evaporate? Up to 70% of water heat escapes through evaporation, Solar Pool Covers also maintain a hotter water temperature by preventing the heat from leaking out in the evening after peak sunlight has passed. Less evaporation is also good for the environment, because you’re using less water to fill your pool.

pool with solar pool cover

Evaporation causes your pool to leak valuable chemicals which can be expensive to replace to stabilize the chemical balance of the pool. The pool cover limits evaporation, preventing chemical loss, saving you money.

If you’ve noticed that chemicals get imbalanced in your pool quickly, try a pool cover instead of accelerating your chemical insertion!

Other Solar Pool Cover Perks

  • The bubbles retain heat at night and on colder days, using sunlight to heat up instead of the temperature.
  • If you have a heater for your pool, you should definitely use a cover to prevent the heat from escaping.
  • The best solar pool covers extend the swim season by heating the pool more than you’d expect. Enjoy those colder swim days in September at the start of the school year by snagging a solar cover!


How do solar pool covers work?

The Solar Pool Cover first absorbs sunlight, heating up the air bubbles on the surface of the cover. The heat from the bubbles heats the pool water, raising it by anywhere from 10-15 degrees (Fahrenheit). Check details on: How do solar pool covers work?

Can I swim with a pool cover on?

No. This can be really dangerous. Depending on the pool cover, there might not be a way for air to get under the tarp if someone pops their head up. I remember hiding in a pool during a hide-n-seek game as a kid and popping up my head under the top only to find that there was no air!

I had to swim quickly to the steps, and I’m lucky I didn’t get disoriented or pass out on the way. Never swim with the cover on!

You’ll see a lot of information on the internet that says that the pool cover makes your pool “safer” by deterring children and pets from swimming. But know that the pool cover  doesn’t prevent kids and dogs from getting in the pool!

Use a proper pool fence or enclosure to prevent accidents.

Do Solar Pool Covers Make My Water Dirty?

No. It might seem gross to have a tarp over the top of your pool, sort of cooking the insides, but solar pool covers actually make your water cleaner. A pool cover prevents dirt and debris from flying into your pool and clogging the filter systems. It prevents dust from building up around the steps when it falls into your pool.

Additionally, by preventing chemical loss through evaporation, the pool cover helps your pool retain important cleaning chemicals.