To extend the swimming season here in Mallorca makes especially good sense, as even when the water temperatures gets too low for comfortable swimming, the days are mostly sunny and very pleasant.

A swimming pool represents a substantial investment on your part, but worth it for the enjoyment it provides for the whole family and friends. Swimming is also generally recognised as one of the best forms of exercise without placing undue stress on any one part of the body.


There are a number of ways to heat your swimming pool, using gas, solar energy or electricity.


Gas would only make sense if you did not have a mains electricity supply. A boiler works well but is expensive to run and generally, unless mains gas is available, would mean either getting deliveries of gas or collecting bottles of gas at frequent intervals.

Solar energy  

It is tempting to use solar energy to heat your swimming pool as it is free and apart from the equipment, installation and maintenance, there are no further running costs.

The problem is that most solar panels used for heating a pool consist of an un-insulated black plastic sheet, with tubes imbedded in it. Water from the pool runs through these tubes and collects the sun’s heat, thus warming the water. This heated water then returns to the pool.

Providing there is a large enough surface area facing the sun, these panels work quite well but only when the air temperature is as high or higher than the pool temperature.

During the spring and autumn and perhaps winter when one wants to heat the pool, the air temperature is lower than the desired pool temperature and because the solar panel in not insulated, most of the heat collected is lost through convection from the solar panel and there is very little left to heat the swimming pool.

The types of solar panel which work, even in cold weather as long as there is sufficient sunshine are those that use glass tubes which are double skinned internally with a vacuum between the layers, thus providing a high degree of insulation.

This type is often used to provide hot water for houses. However these are very expensive even for a small area. To heat a swimming pool to a reasonable degree, it is necessary to have an area of solar panels equivalent to at least half and preferably equal to the surface area of the pool. To have sufficient of this type of solar panels to heat a swimming pool would not be financially viable.


Electricity is the most convenient and readily available method to heat your pool and using an electrically operated water heater works very well but it is very expensive to run.

A very efficient way of using electricity to heat the water in your swimming pool is to use it to run a heat pump and this is the most common and affordable way swimming pool water is heated.


A Heat Pump basically works just like an air conditioning system used for cooling the house, but in reverse. The electricity used to run the Heat Pump does not heat the swimming pool water directly, but instead it is used to operate the compressor in the Heat Pump, which in turn compresses a gas. When this gas is compressed it turns into a liquid and gives out a great deal of heat. This heat is used to heat the swimming pool water by means of a heat exchanger.

After transferring the heat from this liquefied gas to the swimming pool water, the liquefied gas is allowed to expand and it turns back into a gas again. In doing so, it takes in a great deal of heat from the outside air. A constant supply of fresh air is supplied to the heat exchanger by means of a fan.

This cycle then repeats itself over and over again, each time taking heat out of the air, concentrating it and using this heat to heat the swimming pool water.

The electricity used, is only driving the compressor and fan and not heating the swimming pool water directly. This is very efficient as it is the heat in the air which is actually heating the swimming pool.

Even on a cold day, there is still plenty of heat in the air.

Typically, four to five times as much heat is put into the swimming pool water for each KW of electricity used. If electricity on its own was used to heat the pool then for each KW of electricity used, only one KW of heat would heat the pool.

This means that using a heat pump is a very efficient, viable and affordable method of heating your pool.

A heat pump can normally be unobtrusively installed, and most quality heat pumps only have a low level of operating noise.


As a guide to the operating costs, for a typical pool the operating costs would not normally exceed between one euro per day for the smaller units to ten euros per day for large units, while the pool is heating up and then considerably less as the heat pump automatically switches on and off, keeping the pool at the set temperature.

The exact running costs would depend on the surface area of the pool, the volume of water it contains, the ambient temperature of the air, the pool construction, how well drained the soil is, whether the pool is in full sun or partly shaded and the desired pool water temperature.

It is also essential that the pool is covered by means of a pool cover to prevent the heat escaping again, especially during the night or in windy weather. Once the pool reaches the desired temperature, depending on the heat loss from the water, the cost per day is much reduced as the heat pump is then only being used to make up these heat losses.

Please see our Heat Pump page for more details.


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