The electricity consumed in evaporative heat exchanger is exceptionally small, almost all of which is expended into conveying the cool air through the air distribution system.

The energy that causes the air to be cool comes from the free latent energy in the atmosphere also termed as the latent heat of vaporization.

Consequently, the electrical consumption in evaporative heat exchanging can be as little as 8% compared to that of air-conditioning.

In evaporative heat exchanging, water is intentionally made to evaporate so that the surrounding air can be cooled. The more water can be evaporated, the more effective is the cooling of air.