Solar Thermal for Swimming Pools | The Renewable Energy Hub

Solar thermal systems for swimming pools

Solar Thermal Heated Swiming Pool

How does solar thermal heating work for swimming pools?

Americans love their outdoor swimming pools, but even in the hottest parts of the US some water heating is needed.

Solar thermal heating is an ideal solution for heating a swimming pool as it is both efficient and cheaper to run than conventional energy sources like oil and LPG. The cost of heating a swimming pool by traditional means is becoming ever more expensive as the boilers and fuels that are normally used are less efficient and are going up in cost. A solar thermal heating system that is integrated into a swimming pool can meet up to 80% of your pool’s heating and energy requirements. The solar thermal system that is used to heat swimming pools operates in a very similar way to a solar thermal system that would be installed in a house or commercial premises.

The heat will be collected from the solar collector and transferred to the swimming pool using a heat exchanger. There are a few different choices in regard to the type of heating system you can have installed. The first is to have a mixed system which combines a solar thermal heating system in combination with a standard swimming pool heater. Depending on whether you have an indoor or outdoor pool you may be able to have a system where the energy is generated entirely by a solar thermal system.

To gain the most efficiency from a solar thermal system the system must ideally be located to within 25 meters of the house with the solar thermal system mounted on the roof, building or by the poolside. The solar thermal system should also be linked to your home heating system to ensure that during the winter the system can cover some domestic heating needs.

Benefits of solar thermal for swimming pools.

Another benefit to using a solar thermal heating system is that if you have a swimming pool which is outside and the use is concentrated during the summer months you will be utilising the optimal conditions for a solar thermal heating system due to the increased radiation during the summer. A solar thermal heater may be able reach all of your energy requirements for an outdoor pool. You should, of course, have a thorough assessment survey done to accurately determine price and also to determine your swimming pool’s system energy demand.

The swimming pool must ideally be situated within 25 meters of your house and the solar thermal heating would be mounted on either the roof or building or by the pool. The system should also be connected to your main heating system. The size of your system will depend on the size of your pool and the energy performance required. The panels are connected through a sealed circuit that uses copper or stainless steel pipes and that is also chlorine resistant.

 The system should be located on a south facing roof and shading as well as roof aesthetics should be taken into consideration to obtain maximum efficiency. The circuit is also filled with a glycol solution that acts as antifreeze. The panels work when light hits the absorber inside the panel to create heat. The system’s heat is monitored electronically and when it detects that heat is required it sends it through the circuit in the glycol solution to a heat exchanger. The heat is then pumped through the swimming pool water via the exchanger and filter.

Modern designs for solar thermal systems

There are a number of different solar thermal systems available for swimming pools. They range from basic unglazed matting systems to flat plate collectors and advanced systems that use vacuum tube technology.

The older designs of solar thermal panels were ugly and had a short life which made them very unpractical. The new panels are much more aesthetically pleasing and can have a life span of up to twenty years and will have better financial benefits. Solar thermal systems also have low maintenance and are much quieter than standard systems. It will usually only take a few days to have a system installed with minimal disruption but the amount of time will vary from supplier to supplier. The swimming pool will need to be heated to 28C, any higher than this and you will have to increase the chlorine level to prevent bacteria and algae growth.

Solar Thermal Pods

Solar Thermal Pod for swiming poolSolar Thermal Pod

Solar thermal pods or domes are an effective and compact way of heating your swimming pool. Having solar pods installed to heat your swimming pool will help to eliminate a large proportion of your pools heating costs with the additional benefit of little to no heating costs. Solar thermal pods are a compact solution and more solar pods can be added at any time. A solar thermal pod can be installed to complement an existing heating system or they can be used on their own to heat the pool. The more domes or pods that are added the more heat will be produced as well as decreasing the amount of time it takes to heat the pool. Solar pods are suitable for all styles of pool ranging from In-ground pools to above ground pools.

Solar thermal flat plate collectors

Solar thermal flat plate collectors are another way to utilise solar thermal energy to heat your swimming pool. A flat plate collector consists of a flat plate absorber and a transparent cover that allows solar energy to pass through but decreases heat loss. The unglazed type of flat plate collector is used exclusively for outside uses like heating a swimming pool as they gather a high amount of energy. The swimming pool water is circulated directly through the collector where it absorbs the heat.

Evacuated tube collectors

Evacuated tube collectors have many of the same benefits in regard to heating swimming pools. They work slightly differently to flat plate collectors by utilising vacuum tubes which heat up solar absorbers. Evacuated tube collectors can work better in colder conditions and they can reach considerably higher temperatures than flat plate collectors.

Solar thermal matting


Solar thermal matting is a good low cost option for heating your swimming pool during the summer months. Swimming pool solar thermal matting will raise your pools temperature to a comfortable optimum level. Having solar matting installed will help to increase the seasonal time in which you can enjoy your outside pool. Solar thermal matting will help reduce your utility bills and has no maintenance costs. The solar matting will be pre-fitted to interconnecting P.V.C. manifolds that need to be plumbed directly into the swimming pool filtration plant. From here water is passed through the strips of solar matting which is heated by then sun’s rays and in turn delivers heat to the swimming pool.

Heat pumps for swimming pools


Please see our section on heat pumps for information on this.


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