Do Solar Pool Covers Work – Best Bubbles Up or Down (2021)

Swimming in a pool in winter can be a bad dream.

However, there is certain equipment on the market that could turn it into a good one.

One example is solar pool covers.

They are the perfect way to keep your pool warm as well as free from debris.

Now, these solar pool covers are available for every category of the pool.

Irrespective of the different types of solar pool covers on the market, the method of installing one does not change.

Before discussing the correct method of installing one, let us discuss how it works?

Do solar pool covers work?

As the name says, they are like a solar blanket for your swimming pool to keep the debris away and water warm.

The results are somewhat similar to an electric heater for pools.

However, it has an additional benefit of protecting the pool from debris.

Now, how does a solar pool cover work?

The cover works on the same principle as a converging lens.

So, what is a converging lens?

It is a lens that converges all the light to a point.

Thus, with time, the water absorbs the heat generated.

A solar pool cover is the best option on the market to heat your pool without any expenditure.

These pool covers use natural energy, i.e. sunlight to create heat.

Therefore, you don’t have to worry about your electricity bill; you can heat your pool for free!

Should the solar covers bubbles be up or down?

If you have observed a solar pool cover, then you will find that the bubbles are only on one side.


Well, they have been designed to converge light.

Therefore, by concentrating all the bubbles on a single side, the converging process can be increased.

So, which way should the bubbles face?

The side of the bubbles should always face downwards or towards the surface of the pool.


The laws of physics come into play here.

Do you know which lens converges light?

Yes, a convex lens.

So, now imagine the position of bubbles facing upward as well as downwards.

Suppose that the light is falling at 90 degrees on the bubbles.

Which position do you think will converge the light?

If the bubbles are kept upwards, then they will act as a diverging lens.

Thus, the water will not get warm.

It will probably get colder.

On the other hand, if the bubbles are kept downward, they will act as a converging lens.

Thus, all the light will be focused inside the pool.

Therefore, within a few hours, your water will get warmer.

Another reason to place them down is the transfer of heat to the water.

When they are placed upward, the bubbles get overheated and damaged.

Due to this, the heat does not transfer to the pool water.

Let us recap.

You need to put the bubbles facing downwards so that they can converge light into the pool as well as transfer heat to the pool water.

Can you run pool pump with solar cover on – Techniques/Tips to Improve

Here are some tips that will help you improve the results obtained from solar pool covers.

Solar cover bubbles up or down – common problems

  • Never install a pool cover with the bubbles facing upwards.
  • If the two layers of the pool cover are splitting, then switch to a better quality pool cover.
  • If there are tears in your pool cover, then start using a pool cover reel.

Best pool solar cover practices in the industry

Tools you can use to install solar pool cover bubble up or down

  • Skimmer basket
  • Pool cover reel

Solar pool cover bubbles up or down – Frequently Asked Questions

Which way up does a bubble pool cover go?

Irrespective of the type of cover you choose, the bubbles always face down.

If you install them facing upward, then the swimming pool cover will get damaged quickly.

Therefore, always check the direction of the bubbles before installing a solar cover over the swimming pool.

Do solar covers work?

Yes, they do.

They are also the most effective method to warm the water and prevent heat loss.

However, they will take a longer time to heat the pool compared to electric ones.

The results also vary as per climatic conditions.

What is the best color for a solar bubble cover? Are the results the same for all?

Yes, the results vary.

A darker pool solar cover tends to absorb more heat.

Thus, always choose a cover of a darker shade, like dark blue to keep your pool warm.

Can you use bubble wrap as a solar cover?

No, you cannot use bubble wrap instead of a solar cover.


It is because the thickness of the material used for bubble wrap is low.

Therefore, it will not be effective in transferring heat from the sun. It will not last long either.