What Is Evaporative Cooling and How Does It Work?

Evaporative cooling is rapidly becoming the preferred choice for businesses looking to keep large commercial and industrial buildings cool in summer — without the energy costs associated with conventional air conditioning. But what exactly is it, and how does it work? This guide explains everything you need to know.

The Basic Principle

Evaporative cooling is based on a simple and entirely natural process: when water evaporates, it absorbs heat from the surrounding air, lowering its temperature. You experience this phenomenon every time you step out of a swimming pool or feel a breeze on damp skin.

Modern evaporative cooling systems harness this principle mechanically to cool large volumes of air efficiently and cost-effectively.

How an EcoCooling System Works

An EcoCooling evaporative cooler draws warm outside air into the unit using a fan. This air passes through a series of water-saturated evaporative pads. As the warm, dry air contacts the wet pads, the water evaporates — absorbing heat from the air in the process. The now-cooled, humidified air is then distributed into the building through ductwork or direct discharge.

Crucially, the system continuously draws in fresh outside air rather than recirculating stale internal air. This means occupants benefit from a constant supply of clean, filtered air as well as a reduction in temperature.

What Temperature Drop Can You Expect?

The cooling effect depends on the external temperature and humidity. In typical UK summer conditions, a well-designed evaporative cooling system can reduce air temperature by 6–12°C compared to the outside air. On a 30°C day, this can bring indoor temperatures down to a comfortable 18–24°C range.

Does It Work in the UK Climate?

Yes. A common misconception is that evaporative cooling only works in hot, arid climates. In reality, modern EcoCooling systems are highly effective in the UK's temperate summer conditions. The periods of greatest cooling need — warm, sunny days — tend to coincide with relatively low humidity, which is precisely when evaporative cooling performs at its best.

Energy and Cost Efficiency

Unlike refrigerant-based air conditioning, evaporative cooling systems have no compressor and no refrigerant circuit. The only significant energy draw is the fan motor. As a result, EcoCooling systems consume up to 90% less electricity than conventional AC — delivering substantial savings on running costs.

Is Evaporative Cooling Right for My Building?

Evaporative cooling is ideally suited to large open-plan spaces including warehouses, factories, retail stores, workshops, and distribution centres. It is less suited to fully enclosed spaces with very high humidity, or environments requiring very precise temperature control.

Celsius Design can assess your building and advise on the most appropriate solution. Contact us for a free site survey and 24-hour design proposal.