What size pool heat pump do you need?

The right size of pool heat pump determines how quickly and energy-efficiently the pool reaches the desired temperature. Here we show which data sizing requires: water volume, climate, season, target temperature, pool enclosure, and heat loss.

Measure the pool's volume

The initial step in the sizing process is to determine the pool's volume, expressed in cubic metres (m³). This is done by measuring the pool's length, width, and depth, after which the following formulas are applied:

For rectangular pools:
Volume = Length × Width × Average depth

For circular pools:
Volume = π × (Radius)² × Average depth

Where π (pi) is approximated to 3.14.

Determine the desired temperature increase

Next step involves defining the desired temperature increase for the pool's water. In general, a water temperature between 25 and 28 degrees Celsius is recommended. If the pool’s initial water temperature is 20 degrees Celsius and the desired temperature is 28 degrees Celsius, this means a required temperature increase of 8 degrees Celsius.

To calculate the amount of heat required to achieve this temperature increase, the following formula is used:

Heating requirement (kWh) = Volume (m³) × Temperature increase (°C) × Factor

The factor 1.16 is used to convert units from cubic metres and degrees Celsius to kilowatt-hours, which is a standardised method for expressing energy demand in heating systems.

Example: For a pool with a volume of 50 m³ and a desired temperature increase of 8 °C, the heating requirement is:

Heat requirement = 50 × 8 × 1.16 = 464 kWh

Choose a heat pump with the right output

With the estimated energy requirement as a basis, a suitable heat pump can now be selected. The capacity of pool heat pumps is usually stated in kilowatts (kW), which represents the output they can deliver.

As a general guideline, a pool heat pump have an output of around 0.2–0.3 kW per cubic meter of water to ensure efficient heating and an acceptable heating time. A higher value within this range may be beneficial for faster heating or in colder climates.

Example: For a pool with a volume of 50 m³, a heat pump with an output of the following is recommended:

50 × 0,25 = 12,5 kW

Take other factors into account

Several additional factors may affect which size of pool heat pump which is most suitable:

• Climate: A colder climate generally requires a heat pump with a higher output to compensate for greater heat losses to the surroundings.

• The pool's insulation: A well-insulated pool minimizes heat loss through the walls and bottom, reducing energy demand and allowing for a less powerful heat pump.

• Pool cover: Using a pool cover can significantly reduce heat loss through evaporation, which is a major contributing factor to energy demand, and thereby markedly lower energy demand.

• Användningsfrekvens: For pools that are used frequently or year-round, a larger heat pump may be necessary to quickly restore and maintain the desired temperature after use or external impact.

A proper choice of the pool heat pump's The right size is essential to ensure that the pool stays pleasantly warm without unnecessary energy consumption. By carefully measuring the pool's volume, determining the desired temperature increase, calculating the heating requirement, and choosing a heat pump with adequate output, an extended swim season optimal conditions are achieved. In addition, it is important to consider factors such as climate and insulation in order to realize a maximally energy-efficient investment and minimized operating costs.