Heating natural swimming pools

The sun does a fantastic job of heating natural swimming pools up to about 22 degrees in the summer without an external heating system.

However many clients choose to heat their natural swimming pools to boost the temperature of the water to up to 30 degrees and extend their summer swimming season from April to October.

Heating your outdoor natural swimming pool

Heating a swimming pool can easily consume more heat than the average house in the UK, so it’s important to retain heat through efficient design and pool usage.

If you do choose to heat your natural swimming pool, we ensure that the costs of heating your pool are minimised from the outset by proper design, sensible choices of heating methods and taking care in choosing pool covers.

Our heat loss calculator can help you to estimate how much it will cost to heat your swimming pool and the best choice of heating system for you.

What ever heating system you choose, here are our top tips for saving you money when heating natural swimming pools:

Infographic - Top 4 ways to reduce your swimming pool heating costs1. Invest in a cover
An uncovered outdoor swimming pool will lose up to 75% or more of its energy by evaporation from the surface of the water.

A good swimming pool cover will go a long way to eliminating this source of energy loss and can also allow some of the sun’s energy to go through the cover and heat up the water (when it is sunny).

2. Super insulate your pool shell
Once you have reduced heat evaporation with a good swimming pool cover, the next place you are likely to be leaking heat is through the ground.

Our new build pools are super insulated to cut down as much of this heat transfer as possible.

If you have an existing swimming pool and want to improve the heating efficiency then it is possible to retro fit insulation and we can provide you with more information about the scope and cost of this.

For existing pools we recommend applying 75mm of insulation to the inside of the pool shell, for new build pools we always use 140mm of insulation.

3. Turn down the heat
It makes sense to turn down the temperature of the water if you know that the pool will not be used for an extended period of time.

25 degrees is a lovely swimming temperature and reducing the temperature by 1oC can reduce the energy demand by approximately 5%.

4. Go green (and efficient)
When everything possible has been done to reduce heat losses, you can reduce the costs of heating natural swimming pools by installing an energy-efficient pool heater such as an air source heat pump or solar thermal panels.

An air source heat pump is well-suited to heating an outdoor pool during the summer months in the UK when the air temperatures are warm and the efficiency of the heat pump will be high.

As long as the outside air temperature is more than about 12 degrees, you could normally expect an air-source heat pump to deliver between up to seven-times more heat to the pool water than the electricity it consumes. So for 1 Kwh of electricity you can get up to 7 Kwh of heat depending on the outside temperature.

A solar thermal system, consisting of solar collectors on a suitable south-facing roof (or ground-mounted), a pump station and a heat exchanger, can make a significant contribution to heating your pool during the summer months. The running costs of a solar thermal system are very low, and whilst the sun is out it will make a valuable contribution to the heating of the pool.

It’s worth remembering that you will need approximately 50% of the pool surface area in solar thermal panels and this will need to be factored into your pool and garden design.

Of course, because of the variability of the UK summer weather it is best to back solar heating up by a second heating system for pool water temperatures to be reasonable when the sun is weak and to provide sufficient heating to extend the swimming season in spring and autumn.

Can you heat a swimming pond?

Unlike a natural swimming pool which can be heated to 30 degrees, we do not advise heating a true wildlife swimming pond above 24 degrees. Swimming ponds rely on a balanced ecosystem to function properly and heating above this temperate can upset the delicate balance of the swimming pond.

Also, natural swimming pools lend themselves to efficient methods of heat retention (covers and insulation) where as swimming ponds do not because of the high percentage of uncover able planted areas. It would therefore be extremely uneconomic to try and heat a swimming pond.

Despite this, you will find that during a warm summer, a swimming pond, with large planted shallow areas may well heat up quicker than natural or chemical swimming pools.