What is Evaporative Air Cooling?

Innovative, efficient cooling technology

The Oxford English Dictionary defines evaporative cooling as:
‘... the reduction in temperature resulting from the evaporation of a liquid, which removes latent heat from the surface from which evaporation takes place.'

Vent-Tech's Eco Cooling Systems pass warm air from outside a building over wet filter pads. This air is cooled before being pumped into a building. Simultaneously, warm air is vented from the building, allowing the cooled fresh air to circulate inside.

How Evaporative Air Cooling Works

Our eco-cooling systems feature filter pads that are kept saturated with water. An axial fan draws air through the pads, and this air is then cooled and pumped into a room via an air distribution system. The air passes through an insect screen, ensuring that insects do not enter the cooled room. Only pure water is evaporated from the pads, and the water is drained on a regular basis to stop salts accumulating.


Benefits of Evaporative Air Cooling

Evaporative cooling systems feature humidity and temperature controls to optimise the environment being cooled. The maximum level of cooling possible depends on the temperature of the air outside, and its relative humidity – greater levels of cooling are achievable with higher outside temperature and lower relative humidity. Further more, Eco Cooling costs a lot less than conventional air conditioning systems.

The World Health Organisation says that, in temperate climates, the optimum indoor temperature is between 18°C and 24°C.

Eco Cooler Performance Achievable

Please remember that at lower temperatures we recommend that your system’s cooling element is switched off, so you would not see the lower temperatures illustrated here within the working environment.

Relative Humidity


20% 30% 40% 50% 60% 70% 80%
20ºC 10.2 11.6 13.1 14.3 15,6 16.8 17.9
25ºC 13.7 15.4 17.0 18.6 20.0 21.3 22.6
30ºC 17.0 19.1 21.0 22.8 24.4 26.0 27.4
35ºC 20.4 22.9 25.1 27.1 29.0 30.6 32.1


Here in the UK, the level of relative humidity generally drops as the temperature rises. The diagram below shows the relationship between temperature and humidity on a very hot day in a temperate climate like ours.

Frequently Asked Questions

Q: Can you catch Legionnaire's disease from evaporative air cooling?
A: No, because the circulating water is less than 20°C and no droplets are formed. Tests show you are far more likely to catch legionnaires disease in a shower than in a room cooled by one of our evaporative coolers.

Q: How much will evaporative air cooling reduce a room's temperature?
A: This depends on the ambient temperature. On a hot day in the UK the maximum temperature using an eco cooling unit is approximately 22°C, which is about the optimum working temperature.

Q: How much maintenance is required?
A: It is recommended that the air cooling unit is cleaned every 6 months, and we can provide you with a maintenance and service package to take care of this.

Q: Will I get condensation in my building?
A: No. Our expertise in the area is such that we will design a balanced ventilation system with appropriate controls to ensure condensation does not become an issue in your building.

For more information please contact Vent Tech on 0117 971 2163 today.