Indoor Swimming Pool De-humidification / Environmental Control or Air Handling as it is sometimes called is required on all  Indoor pools  to prevent condensation and mold forming in the environment. Due t0 the laws of physics enclosed air with a water source nearby has a high relative humidity. Many pool builders believe incorrectly that you can  just open a few windows or doors to ventilate the room, in practice all you are doing is letting out heat to prevent evaporation and wasting the energy in cooling the pool hall down.

Principles of Environmental Control & Air Handing

The underlying principal of air handling it to maintain a water temperature within 1 degree of the air temperature and thus prevent the water evaporating. We also apply hot air to cold surface such as glass to prevent condensation forming. In nature we call this a due point, as you get on a sunny morning with a cold ground temperature.

Environmental control in Practice

Air Circulation

As you can see form the diagram above there is a constantly circulating system of air that is constantly being dried before being re-introduced across cold surface such as large areas of glass. On most air handing systems there is a secondary system that passes the pool water through to equalize the temperature as seen bellow:

Heat Air Flow This  systems remove excess moisture from the atmosphere in the pool hall, recapture lost heat from the pool water itself, and then recycle the heat in a warm dry condition to keep the pool room comfortable for everyone in there.

The options

Wall Mount Dehumidifiers.Mount Dehumidifier

This system will add either one or two small wall mounted units on the wall of the pool hall floor either low down or high up. They are also available with supplementary air heating coils to allow it to be connected up to your central heating system and heat the pool room. This system is ideal for small swimming pools and hot tubs.


Pool and Air HeaterSingle Discharge – De-humidification with Pool & Air Heating

This system is ideal for small indoor domestic swimming pools. This system provides de-humidification, air and pool water heating and can be concealed in an adjoining room, utilising a special flexible duct and grill kit for simple installation.

Pool and Air Heating SystemDucted Environmental Control System

Ideal for all indoor swimming pool environments. This packaged unit providing a effective heat recovery and complete heating of air and pool water to prevent condensation throughout the pools . Air distribution is normally done via ducting either infloor / overhead or in the walls.


We have been designing and installing air handing systems for many years and have built up a host of partner suppliers to design a system for your pool room. Every system is custom designed to fit the needs of the customer, the pool and the architect. Please contact us for more information or download our specifiers form and email off to us. 

environmental control for pool quote (download)

The Pro’s & Con’s

Pro’s and Con’s

Ducted System

From £25’000 (approx. £175 m3)*

Single discharge

From £12’000 *

Wall Mount

From £3000 per unit*
Installation Cost


Due to the ductwork required and possibly additional central heating boiler


Simpler install but a large peice of equipment


Simple install, heating engineer required on heated units.

Running Costs


Energy is saved in ducting the air and the use of smaller fans, energy is saved in the heat recovery from the air into the pool water


A lot of energy is spent on the fan to blow the air to the other side of the room.


While energy is saved in the air movement often a lot of energy is wasted due to the opening of windows to expel stale (chlorinated) air

Room Temperature Accuracy


This system ensure an accurate air temperature across the room to to ducting. Can also be integrated with air conditioning system for rooms with lots of glass.


Due to the fact the air distribution is from one point full air circulation can not be achieved


Due to the fact the air distribution is from one point full air circuation can not be achieved

Pool Temperature


Controlled from the air handling system to recover energy from the pool and ensure low running costs


Controled from the air handling unit


Separate heating system required



Ducted Systems can hide the duct work in the walls and floor


Two vents on the wall of the plantroom.


Large unit mounted to the wall. Usually multiple units required.



Air can be directed at cold surfaces such as glass to stop condensation in winter


Whilst the air in the room is moving condensation will occur on windows and cold surfaces in cold weather


Condensation on windows and cold surfaces is certain in lower temperatures when the outdoor temperature falls bellow the indoor temperature.

Air Quality

Very Good

Fresh air intake ensures stale air is exhausted whist recuperating the energy.


Fresh air system is optional, heat recover is possible


No fresh air system other than opening a window

Positioning Flexibility


Ducted systems can be installed in most situations remotely from pool room.


Has to be located on wall ajacent to water surface


Has be located on wall near pool. Usually multiple units.

Energy saving

Very Good

Heat recovery ensures optimal running costs, Plus heat exchanger ensure you are not paying to heat clean outside air.


Heat recover from the air is available as an option.




Lower fan speed means lower noise. Variable speed fans an option to turn down the speed of the fan when the pool is not in use


Higher speed of fan is required to throw the air across the room. A switched option is available to reduce operation when the pool cover is closed.


Because the unit is located in the pool room noise from the system is directly transmitted into the pool area.

*All prices exclude a suitable domestic boiler (gas or oil) to provide a hot water feed (lphw) in some instances the house system can be used.

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