What Is The Cheapest Way To Heat A Pool? (Data included)


a solar pool cover on an outdoor pool

Owning a pool is a wonderful thing, but heating it can be very expensive, especially with energy prices currently soaring around the globe.

Some very simple heating and insulation methods can save a lot of money when it comes to cheaply heating your pool.

The cheapest way to heat a pool is by using a solar cover. Solar covers are made of a material that allows sunlight to pass through but traps heat inside the pool. This can raise the temperature of the water by up to 8°C (46°F).

For heating systems where the pool heating is part of the water filtration system, the cheapest way to heat an outdoor pool is to use solar energy. Once installed, solar heating can be combined with the pool filtration system, pumping warm water through your pool at no extra cost.

From my experience with pool heating, it is just as important to take action to keep the heat in the pool once you have it. This has a dramatic effect in reducing pool heating costs.

There is little point in spending money to heat a pool and then allowing that heat to slip away.

In this article I will cover:

  • What is the cheapest way to heat a pool?
  • Is solar, gas or electric pool heating more expensive?
  • What is the cheapest way to maintain pool temperature?
  • How can I heat my pool for free?
  • What is the fastest way to warm up a pool?
  • How can I retain heat for longer in my pool?

What Is The Cheapest Way To Heat A Pool?

The cheapest way to heat a pool is to use solar energy, whether that is in the form of a full installation system such as solar panels or solar thermal technology, or simple solar heating solutions, such as solar covers and solar rings

Solar energy is very economical and effective at pool heating on sunny days. The downside is that you need the sun to use these methods, which makes them less ideal for those regions in the world where there is less sunshine.

Here are the most cost-effective ways you can heat your pool using solar energy, including very simple solutions such as solar pool covers, which personally I have found to be amazing and very effective.

1. Solar Pool Cover

If you’re looking to heat your pool for less, a solar pool cover is the way to go.

Solar covers are made of a material that allows sunlight to pass through but traps heat inside the pool.

A very common material is a “bubble wrap” style material. The sun will heat the cover, and the air in the bubble wrap quickly transfers to your pool, heating your water.

You can purchase solar pool covers that fit your pool exactly or purchase oversized pool covers and simply fold them to suit your pool size. This is the rectangular solar pool cover I purchased for my own pool.

In addition, the air in the bubbles is an excellent insulator, so with a solar cover, not only are you allowing the sun to heat your pool directly, but you also trap that heat in the pool as solar pool covers are also excellent insulators.

Using a solar pool cover alongside other heating solutions such as a simple electric heating pump means you can insulate your pool, keeping it warmer for longer and allowing it to reach higher temperatures.

2. Solar Rings

One way to save money on pool heating costs is to use solar sun rings. Solar sun rings are large floating discs that are placed on top of the water in your pool.

They work by absorbing sunlight and converting it into heat, which is then transferred to the water in your pool.

Solar sun rings are an inexpensive way to raise the temperature of your pool water by several degrees and can significantly reduce your heating costs.

3. Solar Panels

Another great way to save money on pool heating costs is to install solar panels.

Solar panels work by collecting sunlight and converting it into electrical energy, which can then power an electric heater or circulation pump.

Solar panels require a higher upfront investment, but they will pay for themselves over time in reduced energy costs. 

4. Solar Thermal

Solar thermal power is used for water heating. It’s a straightforward technology: the panels on your roof absorb sunlight to heat the water in the water pipes.

This hot water is then transported to your pool.

5. Solar Mats

Solar mats are a fantastic way to get a very cost-effective solar thermal solution.

Black PVC mats with a large surface area are connected parallel to your water pump. The black mats lay in the sun and get very warm. The water flowing through the mat is then heated.

As they pump the water through the mat, they pump warm water into your pool.

It’s important to note that you need to connect the mat in series with your current water pump or filtration system. This is very easy to do with above-ground pools.

Is Solar, Gas Or Electric Pool Heating More Expensive?

On average, solar heating is generally the most affordable option.

As the cost of each type of heating varies depending on a range of factors, including the size of your pool, the climate in your area, and the price of natural gas or electricity, it’s tricky to make general assumptions about the cheapest integrated pool heating system.

According to Poolstore, a small 8000-litre pool needs 150kw of energy to raise the temperature by 15°C. [source]

Using this pool size and required energy, the following shows how much it would cost to raise the pool temperature by 15°C based on current 2022 UK energy prices.

Pool HeaterTemperature IncreaseCost (2022 UK)
Solar (unknown)15°CUnknown
Electric (34p/ kWh)15°C£51.00
Gas (10.3p/ kWh)15°C£15.45

1. Solar Heaters

Solar heaters are the most economical option for heating your pool. Solar energy is free, so once you’ve invested in a solar heater, your only ongoing operating expense will be the cost of circulating the water through the system.

I live in a relatively cold part of the world, in the northern hemisphere. Although solar heating would be fantastic for outdoor pools in my region in the summer months, we would have a short swimming season with little to no heat generated in the winter months if we rely wholly on solar energy.

Although energy taken directly from the sun is free, you must still factor in the cost of pumping your water supply through your filter and through any solar heating panels.

2. Electric Heaters

Once upon a time, electric heaters were affordable to run, but given the current soaring cost of electricity in the UK, it is best to calculate how much your electric heaters will cost to run with current electricity prices in your region.

At present in the UK, electricity is far more expensive than gas.

3. Gas Heaters

Gas prices can fluctuate wildly, so it’s hard to predict how much it will cost to operate a gas heater over the course of a season.

Again, it is safest to find out what you are currently paying per unit of gas energy and calculate your individual operating costs based on your gas heater consumption.

What Is The Cheapest Way To Maintain Pool Temperature?

Taking the same-sized pool, the following table shows the cost of maintaining the heat of a pool based on solar, electric, a gas heating pump. These costs are based on energy prices in northern Europe in 2022, which are currently very expensive.

Pool HeaterDaily Heat Maintenance Cost
Solar PanelsFree
(Although filter pump running costs must still be accounted for)
Electric Heaters£39.44
Gas Heaters£11.60

Here are the calculations, and the assumptions made to compile this heating data.

  • The pool size for the following heating data is 10m x 5m x 2m (Length x Width x Height)
  • The water volume is 100,000 litres. (Volume = Length x Width x Height)
  • To maintain a water temperature of a 100,000 litres pool, 116kW of heat is required each day. [source]
  • Assuming your heating device is running for 1 hour.
  • Electricity price = £0.34 per/kWh
  • Gas price = £0.10 per kWh
  • No heat loss is accounted for. Assumed it is a perfect system.

How Can I Heat My Pool For Free?

If you want to heat your pool for free, then your best bet is to use the power of the sun.

Solar heating systems use solar panels to collect energy from the sun and convert it into heat. This heat is then transferred to the water in your pool, raising the temperature.

Solar heating systems are available in a variety of sizes and can be custom-fit to your pool.

What Is The Fastest Way To Warm Up A Pool?

The fastest way to heat a pool is by using a gas heater.

Solar heaters are the most economical option, but they can take some time to raise the temperature of your pool water by a significant amount as it depends on how much sun is in your region.

How Can I Retain Heat For Longer In My Pool?

One way to retain heat for longer in your pool is to use a solar cover. Solar covers work by trapping heat in the pool water and preventing it from escaping into the atmosphere. They are an inexpensive way to keep your pool warm and can significantly reduce your heating costs.

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Another way to heat your pool cheaply is by using a solar blanket. Solar blankets are made of a material that reflects sunlight and retains heat.

Solar blankets are available in a variety of sizes and can be custom-fit to your pool.

Final Thoughts

There are a few different ways to heat a pool, and the costs can vary widely.

The three most common methods for heating a pool are gas heaters, electric heaters, and solar heaters.

Solar heaters are the most economical option for heating your pool since solar energy is free once you’ve invested in a solar heater.

One way to save money on pool heating costs is to use solar sun rings which absorb sunlight and convert it into heat or use a solar pool cover, which is a very cost-effective way of heating and insulating any pool.

Solar panels require a higher upfront investment but will pay for themselves over time in reduced energy costs, making them more economical in the long term.

Happy swimming!

Louise Byrne

Hi, I am Louise and I am obsessed with swimming. I spend my free time in the water or getting ready for my next water adventure.

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