Choosing a Heating System for your Swimming Pool

Explore your options for heating indoor and outdoor pools, available at Compass Pools.

When choosing a heating system for your pool there are a number of factors to weigh up, these include the cost of installation, cost of running, convenience and temperature accuracy if there is a dependency on the weather and your swimming season.

The table and information below will help you understand the options available.


Heat Pump Medium Low High Ambient Above 8° Medium
Solar Slow None Low Ambient and Sunlight High
Gas/Oil Fast Low High None Med
Electric Fast High High None Low
Compass Pools Outdoor Pool
Compass Pools Outdoor Pool

Running costs of a heated pool

To accurately identify the running costs of a pool there are a number of factors. These will largely depend on the outdoor temperature and weather and the amount you use your pool. To give you a rough idea, in 6 months of the swimming season, a heat pump will cost approximately £5 per day to run a 10m x 4m compass pool at 28 degrees Celsius. This will vary through the season costing more at either end when the weather is worse than in the middle when it could be considerably less. The table to the right will help you to compare this to other options.

Indoor pool running costs you could expect up to £10 per day for an average family pool when you take into account the environmental control costs as well. Swimming pool running costs are a common question. There is no exact answer to “how much does it cost to run a pool” but this should help give you a guide.

Compass Pools Man in pool

How to heat a swimming pool

Basic swimming pool heating can be achieved using a heat exchanger (radiator for pools) connected to your existing heating system. Compass will connect up the heat exchanger to the pool, you can then have a heating engineer connect this using a motorised valve to your existing central heating system. Find out your other options for heating a pool here.

heat pump swimming pool

The costs of a heat pump

In today’s climate and economic conditions, a heat pump provides one of the cheapest and most environmentally friendly ways of heating your pool. Using electricity heat is taken from the air and concentrated down into the pool water delivering an efficiency of up to 5 times the electrical energy put in. These can heat a pool up to 40 degrees C in outdoor temperatures down to 15 degrees C and up to 30 degrees down to 10 degrees C average ambient temperature. i.e in an average UK year, it will perform well between March and October. For those looking to swim, all year round a hybrid system should be considered using fossil fuel to supplement during the cold weather. Want to know how to improve the efficiency of your pool, then click here!

A heat pump will cost approx 50p per hour and will range in operation from 4 hours per day to 24 hours in very cold weather. Running costs average out to approx £150 per month depending on the ambient temperature and length of the season. Compass use between a 14kw and 19KW heat pump (heat output not energy consumption) depending on the size of the pool. 19kw is the largest heat pump that can be installed on a single-phase electrical supply (most domestic UK houses). Compass can also supply a conventional gas or oil boiler for your pool. This is only recommended for those looking to swim all year round, and not concerned too much with running costs.

solar powered pool

Solar powered heated swimming pool

Historically swimming pool solar heating systems in the UK have been quite ineffective as they have utilised one of two methods. Either Black Panel matting where the pool water is passed through a plastic mat to harness the energy from the sun. This is moderately effective when the ambient temperature is warm but becomes a radiator when it is cold, cooling the pool water.

The alternative method is Evacuated heat tubes. These are up to 98% effective at harnessing the heat from the sun, however, up until now a heat exchange has been required to prevent pool water from passing directly through the tube as this will corrode them. This heat exchanger introduces efficiency to the system. The new compass pools solar panels are lined with Borosilicate (Pyrex) Glass which does not corrode and maximises this efficiency even on cloudy days. 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.

Outdoor Pool Water Feature

Other energy sources

Compass can hook in via a heat exchanger to virtually any hot water-generating energy source such as a ground source heat pump or even wood pellet heating! This must be capable of producing 60-degree c water temperature to work effectively during the seasons you want to swim.

Click here for more information on the top 6 pool heating options available in the UK.

Dipping feet in the pool

Hybrid heating systems

For those looking to swim, all year round and willing to invest upfront a hybrid system is the answer. With this method, we will combine a primary system such as a solar or heat pump that is ambient temperature/weather dependent with a fossil fuel or electric system to ensure a constant pool temperature is maintained. The hybrid system will monitor the outside air temperatures and heat output from the primary source. If this drops below a set threshold the system will automatically switch to the alternative source. This gives the best of both worlds, energy savings where available, but a constant pool temperature when you need it.

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