Slat swimming pool_heating cover

Swimming Pool Heating Covers – We Got You Covered

Swimming Pool Heating Covers – We Got You Covered

It doesn’t matter which way you look at it, 80% of the heat energy injected into the pool is lost through its surface.

To heat a swimming pool  we need energy, to retain that 80%  we need a swimming pool heating cover, the question is which cover suits you best.

Swimming Pool Heating Covers - Water evaporation from swimming pool without cover
80% of your heating energy evaporates through the surface.

PVC electric roller slat swimming pool heating covers.

Swimming Pool Heating Covers
Pvc slat roller installed on the pool terrace

Why PVC is better than polycarbonate – on the Costa Blanca

Strange but true, PVC is a better choice than polycarbonate, on the Costa Blanca for swimming pool heating covers.

Whilst the sales blurb may suggest polycarbonate benefits solar gain, it also causes havoc with salt stains, and calcium carbonate falling out of saturation due to LSI violations, (too much heat on the top side of the wet cover). Then the polycarbonate becomes brittle and algae grows inside..

Alternatively, a PVC slat swimming pool heating cover will serve you well without these problems and for as long as 25 years. Electrically powered for ease of use, and a range of colour options.

Safety first

Swimming Pool Heating Covers - Closed Safe PVC Secured Cover
Child and pet safty. A closed safe PVC secured cover

A swimming pool is dangerous. A covered pool that is not secure is extremely dangerous. A child or pet fallen under the cover is very unlikely to get out, without help.

The PVC swimming pool heating cover is installed with safety anchors, that make it rigid and secure.

Yes, it is child and pet safe.


Swimming Pool Heating Covers
PVC slat cover motor installed in the pool

A refurbished or new pool has the design benefit of being able to build the swimming pool heating cover motor inside the pool. Now you have all the benefits of the cover with no loss of space.

Whether installed on the swimming Pool crown/terrace or within the pool – a slat cover looks great.

Cost and performance benefits of swimming pool heating cover.

Whilst the slat swimming pool heating cover is not a cheap consideration, given its performance benefits it soon pays for itself. Save power, long life, and potentially saves lives. The Return on Investment due to reduced heating and water chemistry costs is very high. The quality and usability of the enhanced swimming pool are considerable.


Without the swimming pool heating cover, we know 80% of the input energy is lost through the surface.

A PVC cover will reduce evaporation by a staggering 95%. This in turn saves approximately 70% of the energy demand.

The PVC cover by reducing energy demand enables far greater water temperature to be achieved. For all year around swimming pool water comfort, an electrically controlled PVC cover, with stepless inverter heating, and inverter flow control ticks all the boxes.

Expect it to last as long as 25 years.

Cost of swimming pool heating cover.

More expensive than plastic bubble covers, but much more substantial. The return on investment value is extremely high.

Reducing heating costs by as much as 70%.

Hygiene and Chemical effect of swimming pool heating cover.

When the cover is closed the water is sun protected. This means less CYA (chlorine stabiliser) demand. Less stabiliser demand allows lower and more efficient chlorine disinfectant potential (as long as you balance it correctly). No sun also means less photosynthesis so less work for disinfectant to deal with environmental micro-organisms (aka algae).

The LSI saturation index is also affected. CO2 off gasing is reduced therefore less pH fluctuations.

All very well but at the same time consideration must be applied to the total reversal when the cover is open.

The use of salt to chlorine systems  are not advisable and definitely not with a cover. The corrosive effect and staining with 3000ppm of additional TDS (dissolved solids) is a really bad idea.

Combined with Inverter heating and circulation.

We know that 80% of the heat is lost through the surface. But let’s look and understand a bit more.

  • Heat is lost due to evaporation.
  • Evaporation takes place due to dry wind, and air temperature at + 2c or lower than the water temperature.
  • At the beginning of the article, we clearly state that 80% of heat energy is lost through the surface. Therefore the more energy used the more it loses when in a state of evaporation. The cover prevents evaporation.

Thoughtful consideration of swimming pool heating cover.

If the swimming pool is heated to a set point of 28c but the air temp is 15c, the potential for evaporation and heat loss is high.

An air source heat pump is at its most efficient when the air/water temperature are both 27c or more.

When the swimming pool is not covered and the air temperature drops to less than 27c – for example, 15c – the heat pump becomes less efficient and therefore less able to heat as much flowing water and most of that input energy (80%) will be lost through the surface.

When the pool is covered, as stated above we are able to save 70% of the input power.

Two inverters are better than one – especially using a swimming pool heating cover …

So when air is 15c (at night) it’s important to maintain the water temperature at the set point of 27c or more. This is why the inverter heat pump combined with the inverter programmed flow circulation works so well when combined with a good cover.

As the heat pump loses efficiency, we slow down the flow rate of the circulation pump, so in effect, it regains its efficiency. We also reduce the heat pump’s power potential (and even further reduce its noise). The water temperature is retained and the power is reduced..

The next day when the sun comes out the heater regains its efficiency so its schedule alters.

Air temperature  – controlled water temperature the hare and tortoise effect.

Lower air temperature = lower heating efficiency – but warm water that’s maintaining temperature at low demand flow rates is more economical because both stepless inverter heating and programmed inverter flow are all using very little power. Less input energy to maintain = less input energy to lose.

Controlling heating power with a matched reduction in flow rate energy the swimming pool will lose less heat – the same principle as the tortoise and hare.

Then the next day as the air temperature increases the stepless inverter becomes even more efficient therefore flow rate increases to put back any small loss in temperature. The PVC slats will trap the heat, whilst the stepless heater and flow programmed inverter circulation pumps provide controlled energy.

Solar thoughts to heat a swimming pool.

Solar PV panels roof mounted
Solar PV panels roof mounted

Having already discounted the polycarbonate solar slats, as stated above, how can solar benefit?

With the cover closed we save 80% of heat loss through the surface. At night combined with inverter heating and circulation we maintain temperature for minimal cost, and controlled minimal losses.

During the day the solar panels provide an abundance of energy, but by reducing the amount of energy required for heating the pool, the solar system is able to re charge its batteries and possibly provide an excess back to the grid.

The heating system is not, and does not want to be related to solar power. Because the heating system needs to do its job regardless of the sun. This is the very reason why solar heating is no good, you need the heating most when the sun is hidden by clouds, and you need a constant small amount of energy all night to prevent conductive cooling..

Conclusion of swimming pool heating cover.


Matched with modern inverter heating and circulation the PVC slat cover is probably the best solution. If you can install it within the pool then it looks sharp and gets a thorough wash each time it’s rolled on / off.

Swimming pool heating

Return on Investment.

With a 25 year life expectancy, this also becomes a solid investment and although more expensive up front, over time it is the cheaper option.

We recommend the cover gets a simple cleaning schedule and not to leave the cover on for extended periods without opening. Certainly, an unattended pool is best kept with cover open.

Inverter flow


The hygiene/chemical strategy needs consideration. Accurate dispensing allows for accurate planning, being able to program the key times to dispense disinfectant and pH correction based on usage and professional testing. With a covered swimming pool the chemistry needs to be quantitive because the water needs to be ready.

Intellichems dispensing


A slats system is child and pet safe. This is a huge benefit. The pool is closed the children and pets are safe.


A choice of colours, neat tidy and easily moved out of the way  Get it submerged for the ultimate look.

Slat swimming pool_heating cover

How to buy a Slat swimming pool heating cover.

Techpools provides a comprehensive heating solution for swimming pools including the full design supply installation and after care service of PVC slat swimming pool heating covers.

Article written by Simon Spragg.

AI bots are specifically not used in creation of Techpools content.

Contact Us

For more information about how we can help you have the perfect swimming pool, please contact us using the details below:-

Simon Spragg

Tel: +34 659 999 044