Domestic pools – indoor

The problem

An indoor swimming pool is a wonderful leisure and exercise environment, but there are many important factors to consider when planning and designing a domestic pool. Maintaining a comfortable pool environment requires the pool water and air to be heated, and this is a significant energy use. As a result of continuous evaporation while the cover is removed, the pool water loses a significant quantity of heat, and the resulting warm, humid air is not only uncomfortable, but the high humidity poses real problems for the building structure. Left unchallenged, high humidity can be a major problem in indoor swimming pools and spas. Prolonged exposure to high humidity causes walls, decorative finishes and roofs to deteriorate rapidly. High humidity causes personal discomfort and unless the environment is controlled to a comfortable humidity in the range 55%-65%, bathers will not benefit from enjoying the use of their swimming pool.

The solution

Excess humidity must be removed from the pool hall to protect the pool building from destructive condensation and moisture damage, whilst maintaining a safe and comfortable leisure environment for bathers. In the past, the conventional approach to combating humidity came in the form of wasteful air extraction from the pool hall. The advanced range of Calorex heat pump dehumidifiers provide an efficient and economical solution without using large quantities of fresh air.


From wall-mounted dehumidifiers for humidity control, with options for air heating, to the Variheat range of sophisticated environmental control systems, Calorex have systems for every domestic pool. By recovering the latent energy in the moisture laden air of a pool hall using a heat pump dehumidifier, a Calorex swimming pool dehumidifier will reduce the humidity in the pool hall, while returning energy to heat the air. Variheat systems start with ducted dehumidifiers, through to sophisticated environmental control systems with heat recovery to pool water.

Heat pumps for water heating

Calorex Pro-Pac swimming pool heat pumps are specifically designed to economically provide swimming pool water heating. Calorex Pro-Pac Y heat pumps are designed to operate in air temperatures as low as -15°C and are suitable for heating the water in indoor pools all year round.

Cost savings

Removing humidity from the air enables Calorex to absorb latent energy and return it to the air as useful heat. The heat pump technology converts 2.5kW to air heating for every 1kW of electricity consumed – a real bonus for running costs! For water heating, Calorex heat pumps can save up to 75% for both operating costs and carbon savings against direct electric heaters, and up to 47% operating cost saving against fossil fuel boilers and up to 60% carbon saving against fossil fuel boilers (based on UK energy costs).


Fully self-contained systems, Calorex dehumidifiers require minimal installation. When it comes to operation, Calorex units offer quiet, reliable and safe performance. Flexibility is built-in. Wall mounted dehumidifiers come with an adjustable air discharge allowing air to be directed in an 80° range between horizontal and vertical, thus allowing installation at high or low level. Variheat systems are available in a wide range of configurations to suit a variety of pool types and plantrooms. On the basis of pool surface area, water temperature, air temperature, humidity and bathing activity, Calorex dehumidifiers and heat pumps can be designed to accommodate any requirement. All products are supported by an in-house applications department, distributors and service network.

Associated products

Variheat III


The Variheat range are sophisticated air handling units incorporating heat pump dehumidification… ...read more

AA300 AA500

AA 300-500

​​The AA 300 and AA 500 are premium air handling units incorporating heat pump… ...read more

Pro-Pac 8-22

Pro-Pac 8-22

​​Pro-Pac heat pumps are specifically designed for swimming pool heating. Heat… ...read more

DH33/55 wall mounted

DH 33

The DH 33 is a high performance, low cost wall mounted dehumidifier with integrated air… ...read more

Floor standing DH75/110

DH 75AX-110AX

The DH 75 and DH 110 are floor standing high performance and high capacity dehumidifiers.… ...read more

Dual Purpose Water Chillers

WA 634ACL-1234BC

Calorex water chillers are ideal for economically cooling swimming pool water. The 34 range… ...read more

DanX 1/2/3 XD

The DanX XD compact units are energy and cost-efficient solutions that combine ...read more

More information

Calorex Variheat

An indoor swimming pool featuring...read more

Calorex Variheat

An indoor swimming pool featuring...read more


Product Catalogue...read more


Contact (UK)

Certikin International Ltd (H&V Department) 01993 778855
Contact Certikin

Contact (International)

+44 (0)1621 856 611
International Enquiries

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