Choosing a Heating System for your Swimming Pool.

When choosing a heating system for your pool there are a number of factors to weigh up. For most homeowners, this typically includes:

  • Installation costs
  • Running costs
  • Convenience of use
  • Temperature accuracy
  • Weather dependency
  • Their preferred season for swimming

The table and information below should help to weight these up for you.

pros and cons of swimming pool heating

heating of a pool, running costs compared graph.

What are the running costs of heating a pool?

Swimming pool running costs are a common question. There is no exact answer to “how much does it cost to run a swimming pool” but this should help give you a guide. 

There are a number of factors you will need to consider in order to accurately estimate the running costs of your pool heater. These will largely depend on the ambient outdoor temperature and the amount you use your pool.

As a rough guide, to keep a 10m x 8m pool at 28°C over a six-month swimming season, you can expect a heat pump to cost approximately £5 per day to run (costing slightly more at either end of the season but less in the middle, when the air temperature warmer).

Indoor pool costs are up to £10 per day for an average family pool, which is due to the environment control you need for the pool room in addition to the pool itself.

The graph to the right provides a rough price comparison of the various heater fuel types.

Heat exchangers and a central heating system

Basic swimming pool heating can be achieved using a heat exchanger, which is essentially a pool radiator, that is connected to your existing heating system. At Compass Pools, we can connect your heat exchanger to the pool and recommend a heating engineer that will install it safely into your existing central heating system, using a special motorized valve. The cost of a heat exchanger to heat your pool is similar to the price of adding an additional radiator into your home, plus some electrical work.

Compass can use a heat exchanger to connect to any hot water source, including ground source heat pumps or even wood pellet heating! The source must be capable of producing 60°C water temperature to work effectively during the seasons you want to swim.

Heat pumps

compass pools 19kw swimming pool heat pump

Heat pumps provide one of the cheapest and most environmentally friendly ways of heating your pool. Running on electricity, they work by taking heat from the air and concentrating it downwards into the pool water, generally delivering an efficiency of up to 5 times the electrical input.

Heat pumps can heat a pool to a maximum of 40°C in outdoor temperatures of 15 °C, and up to 30°C in ambient temperatures of 10°C. This means that in the UK, heat pumps are an effective way of keeping your pool warm from March to October. If you are looking to swim all year round, a hybrid system that utilises gas or oil may be more cost-effective during cold weather.

A heat pump will cost approximately 50p per hour, and you can expect it to be running for anywhere between 4 and 24 hours a day, depending on the ambient temperature and length of the season. This means that the running costs to heat your pool average out to approximately £150 per month. At Compass Pools, we match the power of your heat pump to the size of your pool, typically installing pumps that have a heat output between 14kW and 19kW. 19kW is the largest heat pump that can be installed on a single-phase electrical supply found in most UK homes.

Gas and oil heating

If you are intending to swim all year round and are concerned about cold weather, we can supply a conventional gas or oil boiler for your pool. However, this is typically the most expensive option to run and we would not advise it if you are conscious about the price of your pool maintenance.

Heating your pool with direct solar

Direct Pool Solar Heating

Two solar heating methods have commonly been used in the UK, despite both having a limited effectiveness.

The first is black panel matting, where pool water is simply passed through a plastic mat to be heated using the warmth stored from the sun. This is moderately effective when the ambient temperature is warm, but will actually cool the water once the temperature drops.

Alternatively, some pools use evacuated heat tubes. Although these are up to 98% effective at harnessing the heat from the sun, older systems require a heat exchanger to be installed, as pool water cannot pass directly through the tubes without corroding them. This addition of a heat exchanger ultimately reduces the efficiency of the system.

At Compass Pools, we have been installing direct solar heating panels for clients since 2014. Our solar panels are lined with Borosilicate (Pyrex) Glass, which maximises their efficiency even on cloudy days, and will not corrode. The frame is made of anodised aluminium and several panels can be coupled together. A small backup system is recommended for the beginning and end of the season and for unusual climate changes.

Hybrid Systems

For those looking to swim all year round and are happy to make an up-front investment, a hybrid system is the best answer. With this method, we combine a primary system (such as solar or heat pump) that relies on the ambient temperature with a more powerful system, fuelled by electricity, oil or gas as a backup.

The hybrid system will monitor the outside air temperatures and heat output from the primary source, and if it drops below a set threshold, the system will automatically switch to the alternative source to maintain the water temperature. This gives the best of both worlds: energy savings where available, but a constant pool temperature when you need it.

Free Pool Owners eBook by SPATA

Understand what's involved in pool ownership with this free guide by SPATA (Swimming Pool & Allied Trade Association).

SPATA provides standards on swimming pool construction, which all Compass pools meet.

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