Swimming pool heating solutions


Swimming Pool Heating Systems

Commercial and Domestic pool heating

There are a number of ways to heat your swimming pool. From solar power and heat pumps which use the power of the sun and temperature of the air to warm the water to gas and oil fired boilers which heat your swimming pool with a far higher degree of control.

Heating a swimming pool in the most effective manner depends on where you live and how much of the year you intend to swim. Typically we find a boiler is essential as, at a minimum, a backup facility should an air source heat pump or solar panels fall short of the pools energy needs, and especially if the pool is to be used in winter months where sunshine can become a rare commodity and ambient air temperatures can be very low.


There is growing popularity of heat pumps, either air source heat pump ( ASHP ) or ground source heat pump ( GSHP ) for swimming pool heating due to their ease of installation, low operating cost and low carbon footprint generation. Either type of heat pump can be direct ( heats the pool water only ) or indirect ( via a heat exchanger ). Indirect units can heat areas other than the pool, such as a changing room, but are less efficient.

Heat pumps work in a very similar way to a fridge, only in reverse, by extracting heat in the surrounding area ( air or ground ) and using a compressor to increase that ambient heat to a useful level, but the components within a heat pump use electricity so its not entirely free energy ( unless the electricity comes from PV panels ). During the summer a typical heat pump provides around 4 times more heat to the water than the power they consume in electrical input, this is often referred to the CoP (Coefficient of Performance ).

During the winter this performance drops as the ambient heat drops and so the efficiency (CoP) of a heat pump varies between 2.5 to 3.5…. and stops working completely below -15C for everything but commercial units.

There are 2 other points to consider when contemplating an air source heat pump in particular.

  • ASHP’s have fans and compressors so are not silent and the noise output can vary between manufacturers and models.
  • Due to the recent popularity of heat pumps there are many products from an unknown source so it is important to ensure that the chosen product can be supported by the supplier and the claimed performance can be supported for UK conditions.

Ground source heat pumps utilise a more reliable ambient temperature but the installation costs are far greater due to the ground works required, and have the same drawbacks in terms of noise. Whilst GSHP remains an option for swimming pools it is rarely used.


The concept of the solar heating system gathering free heat from the sun is attractive and will work for swimming pool heating however in the UK climate it is difficult to maintain the desired temperature in the pool and so a supplementary or backup heat source is often used. One other consideration is the size and/or number of panels which can be a challenge to site in terms of space and being south facing. One other drawback is they produce no power at night so unless some form of power storage is employed the swimming pool is likely to cool off during the twilight hours (we would always recommend using a pool cover when not in use to reduce heat loss and provide safety).


Boilers are a common and effective method of swimming pool heating. They are available as either a purpose built “direct” type, where swimming pool water passes directly through the boiler, or an “indirect” type, where a conventional boiler is linked to an additional external heat exchanger. The part of the heating equipment in contact with the pool water must be specifically designed to be compatible with the chemicals contained within swimming pool water and the required flow rates.

Of the different boiler types, mains gas boilers will offer the lowest running cost as oil and LPG are higher priced fuels although both Oil and LPG are viable solutions should natural gas not be available.

We at Alexandra Heating Services do not install Certikin boilers as we believe we have a superior solution which utilises the much respected and WHICH recommended Viessmann boilers coupled to a bespoke heat exchanger with titanium internals to ensure great performance and longevity all controlled using the “poolsmart” controller. These Viessmann condensing boilers offer fantastic reliability and high efficiency and reward their owners with years of trouble free service and lower energy bills. Our customers love them.

We can happily advise on the right solution for your needs, be that a boiler only or a combination of renewable energy and backup systems, and when it comes to the boiler side of things