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Indoor Swimming Pool Humidity Control

CFW undertakes climate control projects for indoor swimming pools and other damp environments. We will work with you to determine your needs and create a custom solution for indoor pools of any size. Turnkey services with system design and construction, component provision and installation and after-sales services are available and we also supply components such as fans, dehumidifiers and heat exchangers. Contact us or visit for more information about our dehumidifiers.

Indoor swimming pools produce large amounts of water vapour containing corrosive chemicals such as chlorine or bromine. The combination of moisture and chemicals can cause considerable damage to the building, as well as an unpleasant environment, if it is not controlled with an adequate ventilation or dehumidification system. The suggested maximum relative humidity (RH) is 60%.

It is also advantageous to recover heat from the dehumidifier using a heat exchanger, as the process of removing moisture from the air makes the room feel cooler. New air introduced into the space may have to be heated for best results. The presence of a heat exchanger, however, makes adequate humidity control even more important, since warmer temperatures will tend to increase evaporation and since the equipment is very susceptible to chlorine corrosion. Failure to take this into account is one reason for the common problem of installing inadequate dehumidification systems that end up resulting in unforeseen costs.

In general, one air change per hour is enough if a pool cover is used.

The large amounts of water that continually evaporate from pools can cause high humidity that make for an uncomfortable and unhealthy space. Air moisture can also cause fabric and building damage, both by condensation and chemical damage from chlorine or other antimicrobial substances added to the water. Rust, paint blistering, mould and structural support damage are some of the possible problems.

Pool water can be kept at a temperature of about 27 °C and pool air at about 29 °C. While personal preferences may differ, the air temperature should usually be slightly above that of the pool water to limit evaporation. This temperature control is often accomplished by means of heat exchangers. Often much of the heat produced is lost through ventilation to control humidity. This results in high energy costs both from heating and from continuous ventilation. However, with appropriate technology condensate and heat can be recovered to save energy.

Dehumidifiers may have a higher capital cost, but their operating costs are similar to those of heat recovery ventilators. They also offer closer control, especially during summer, as the indoor humidity levels are not dependent on outdoor humidity levels. A requirement for larger dehumidifiers or longer running times, and higher maintenance and operational costs, will result if the room temperature is markedly lower than the water temperature. While refrigerative dehumidifiers are running, they will also heat the air that has been dehumidified. This is a useful side effect of the method by which they reduce the ambient RH, but may not always be enough to heat the area to a comfortable temperature.

The operating costs of a dehumidifier are often outweighed by the savings that will result from avoiding expensive repairs from damage caused by high moisture levels. The costs of a dehumidifier system will depend on the size of the pool, the size of the room, the price of electricity and the required running times.

Ideally, the indoor pool should be planned with environmental control in mind, but modifications can be undertaken. CFW can provide a complete temperature and humidity control system, and we pride ourselves on the service we offer.


Contact Us


Cape Town, South Africa (HQ)

3 Parin Road, Parow Industria, 7500, Western Cape

Johannesburg, South Africa

4 Chilworth Road, Founders View North, Modderfontein, Edenvale, 1645, Gauteng


Cape Town, South Africa (HQ)

T +27 (0)21 931 8331
F +27 (0)21 931 3165

Johannesburg, South Africa

T +27 (0)11 452 5830 / 5146
F +27 (0)11 452 5132


Cape Town, South Africa (HQ)

 Johannesburg, South Africa

Mailing address:

P.O. Box 1542, Parow, 7499, South Africa