Less Is More

A fresh air source swimming pool heat pump will prove less expensive to operate, during a typical summer season, than any fossil fuel alternative method

Energy efficiency and low operating costs are features that promote themselves naturally to any prospective heat pump client, perhaps more so now than at any time in the past.

Every pool owner should assess renewable energy options when considering a heating system for an outdoor pool, either as part of the construction of a new pool or as a replacement, or an upgrade of an existing older heating system. “Almost any pool will benefit from using a heat pump, but the benefits will be in direct proportion to the amount of energy used,” emphasises Graham Kneale of Certikin International, UK distributors of the Calorex range of heat pumps.

“In short, the more energy a pool uses, the greater the savings will be. “Far from the popular misconceptions that heat pumps cannot heat pools up in to the 30s, the hotter the pool the more energy it will use and the greater the savings will be for using a heat pump,” Graham points out.


“If sized appropriately, heat pumps can heat large uncovered outdoor pools to 37°C all year around, providing reliable heat at very low cost compared to most other fuels,” he adds. Generally, a fresh air source swimming pool heat pump will prove less expensive to operate, during a typical summer season, than any fossil fuel alternative method. The potential savings will depend upon the nature of the alternative fuels possible.

Calorex offer regular training at their Essex headquarters that is
free of charge to the trade.

Paul Scott of Heatstar expands: “If the project has mains gas available, that may offer an alternative around 12% more expensive than a heat pump. “However, if there is only heating oil or propane gas available, the cost savings achieved by a heat pump are considerably more with oil being around 90% more and Propane 140% more,” says Paul. “A primary consideration with a heat pump is that its heat output would typically be much smaller than an alternative fuel boiler, so clients who require a swift initial warm-up of the pool from cold may be disadvantaged.”


Although swimming pool heat pumps have been applied successfully for decades, domestic heat pumps, using similar technology, have also recently become increasingly popular for heating dwellings and for providing domestic heating and hot water. As Paul points out: “For dwelling heating applications, because much of the annual heating will be required during the winter months, ground source heat pumps offer the best efficiency potential during such times, as fresh air source heat pumps are impeded to a degree as a result of colder fresh air temperatures.

“Where it is not practical to install a ground source system, fresh air heat pumps can be used, but the economics if mains gas is also available can be compromised.” During the typical summer months, the CO2 and carbon emissions associated with utilising a swimming pool heat pump will potentially be some 50% less than those of mains gas, which will be important to many customers.

Paul again: “Although modern gas and oil boilers offer much improved combustion efficiencies, they have also become comparatively expensive to purchase compared to older versions. “Accordingly, the capital cost difference compared to a swimming pool heat pump may not be particularly significant.”

For a typical domestic outdoor pool, say 10 x 5m operated from May to September, equipped with a surface cover, based upon current energy costs, the savings achieved by a swimming pool heat pump per season may be in the region of £124 compared to mains gas, £958 compared to heating oil, £1529 compared to Propane gas and £2666 compared to direct electricity. To avoid misunderstandings, installers should establish the design criteria with both the end customer and their heat pump supplier, making sure it is documented in writing.

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Bosta UK Ltd
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Pollet Pool Group
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Certikin International Ltd
Tel. +44 (0) 1993 778855