Solar Pool Cover Bubbles: Up or Down?

By Kami Turky


A solar pool cover may seem like a straightforward accessory, but there’s more to it than meets the eye. One of the most commonly debated topics among pool owners is the orientation of the cover: should the bubbles face up or down?

The short answer is that the bubbles should face down, touching the water.

While this might seem like a minor detail, the cover’s orientation can impact the efficiency of heat transfer, the longevity of the cover, and the overall cleanliness of your pool.

In this guide, I’ll walk you through the reasons behind this specific orientation, how to maintain the bubbles for optimal longevity, and the best practices for using your solar cover.

Key Takeaways

  • Solar pool cover bubbles should face down for optimal heat transfer and UV protection.
  • To store your pool blanket, ensure it’s clean, dry, and rolled, not folded; store in a shaded, temperature-stable area.
  • Maintenance involves regular cleaning, monitoring chlorine and UV levels, and ensuring bubble-side is downward.
  • You can use a solar cover reel for easier handling and to prevent dragging the cover on rough surfaces.
  • For long-term storage, consider UV-resistant or pest-resistant bags to ensure the cover’s longevity and protection.

Which Way Should the Bubbles Face?

The bubbles should face down. This recommendation is not just a matter of aesthetics or tradition but is grounded in practical and functional reasons.

When the bubbles are oriented downwards, they come into direct contact with the water, enabling them to transfer the sun’s heat directly and uniformly into the pool. 

To put this into perspective, think of the bubbles as a magnifying glass. 

Just as a magnifying glass can focus the sun’s rays to intensify heat on a particular spot, the bubbles capture and concentrate the sun’s warmth, funneling it directly into the pool water below.

The bubbles, when positioned downwards, also provide buoyancy, ensuring the cover remains afloat on the water’s surface. 

However, reversing this orientation, with the bubbles facing upwards, disrupts this efficient heat transfer mechanism. 

The direct exposure to the sun’s UV rays can deteriorate the bubbles over time, reducing the cover’s overall lifespan. 

Moreover, without direct contact with the water, the sun’s rays are diffused before reaching the pool, leading to a less effective and slower heating process.

Another concern to address is the risk of debris entering the pool when the bubbles face up. 

With the bubbles positioned upward, the flat top portion of the solar cover seals against the water and tends to slide around. 

As it shifts, any debris resting on top, be it leaves or other particulates, will fall into the swimming pool, increasing cleaning efforts and affecting the water quality.

How Should I Store My Pool Blanket?

To store your pool blanket, you should first ensure it’s clean and free from any debris or contaminants. Lay it out and use a soft brush to gently remove any dirt from both sides. 

Then ensure give it a good rinse and let it dry completely, as storing a damp blanket can lead to mold and mildew formation, which can damage the material and decrease its efficacy.

Once cleaned, the ideal way to store the blanket is by rolling it. Rolling, as opposed to folding, minimizes creases which can, over time, weaken the material. 

If you have a storage reel, the process is simplified. Begin by attaching one end of the blanket to the reel and ensure it’s wound tightly, avoiding any slack or loose areas.

However, where you store the blanket is just as critical as how you store it. Extended exposure to direct sunlight can be harmful to the materials due to the UV rays, so find a shaded location or use a UV-resistant storage bag. 

Thus, you need to choose an area with a consistent temperature, avoiding places prone to extreme heat or cold. 

This ensures that the blanket’s material remains in optimal condition. Additionally, the chosen storage space should be dry to further prevent mold and mildew growth.

You should also be cautious about the surroundings of your storage area. Avoid placing the blanket under heavy objects that could potentially damage it. 

If you’re considering long-term storage, you can use a pest-resistant bag or container is a good idea because rodents or other pests might find the material tempting to chew on.

How to Maintain Solar Pool Cover Bubbles?

To maintain the bubbles on your solar pool cover effectively, you need to adopt a few crucial practices. 

Here’s a guide on how to properly care for and maintain the bubbles on your solar pool cover:

  • Proper Placement: Always ensure the bubble side of the cover is facing down when in use to prevent the bubbles from deteriorating due to direct exposure to UV rays.
  • Regular Cleaning: Over time, algae, dirt, and other debris can accumulate on the cover. At least once a month, remove the cover and clean it with a mild detergent mixed with water. Use a soft brush or cloth to gently scrub both sides of the cover, then rinse it off with a hose.
  • Avoid Chlorine Damage: High chlorine levels can damage the bubbles on the cover. If you’ve recently shock treated your pool or added a high dose of chlorine, wait until the chlorine level drops back to normal before replacing the solar cover.
  • Monitor Sun Exposure: Even though the cover is designed to absorb sunlight, excessive UV exposure can weaken the bubbles. If the pool is not in use for an extended period, consider using a protective pool cover to shield the solar cover from continuous sunlight.
  • Avoid Dragging: When removing or placing the cover on the pool, be careful not to drag it across rough surfaces, which can damage the bubbles. Using a solar cover reel can help prevent this kind of wear.
  • Proper Storage: When the cover is not in use, particularly during off-seasons, roll it and store it in a cool, dry place. Keeping it away from direct sunlight and ensuring it’s clean and dry before storage can prevent premature deterioration.


What Side of a Solar Pool Cover Should Touch the Water?

The bubble side of a solar pool cover should touch the water.

Does a Solar Pool Cover Need to Touch the Water?

A solar pool cover needs to touch the water to ensure effective heat transfer and to maintain consistent pool temperatures.

How Fast Does a Solar Cover Heat a Pool?

A solar cover raises pool temperatures by 10-15°F in 6 days, depending on sunlight.

How Should You Use a Solar Cover on a Pool?

You should use a solar cover on a pool with the bubble side facing down, ensuring direct contact with the water for optimal heat retention and to reduce evaporation.


As promised, we’ve covered the ins and outs of solar pool cover orientation, its importance for heat retention, and the best practices for maintaining its efficiency.

And if you ask for my advice, I’d recommend investing in a good quality solar cover reel. 

Not only will it simplify the process of placing and removing the cover, but it also ensures even wear and minimizes potential damage, thus extending the lifespan of your cover.

Do you still have any questions? Feel free to leave them in the comments below.

Kami Turky

Kami is a solar engineer with nearly a decade of experience in researching, testing, and reviewing various solar products. He has also provided technical consultation to several organizations on the best ways to incorporate solar energy into their operations. When he’s not busy helping others find the best solar solutions, Kami enjoys spending time outdoors, hiking, camping, and exploring the natural wonders of his home state.

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