Why it works
How evaporative cooling works
Short answer
Water needs energy to evaporate. It takes some of that energy as heat from the water, air or skin around it.
The simple explanation
- ✓Evaporation is faster in dry air.
- ✓Moving air speeds evaporation.
- ✓Evaporative coolers add moisture, so performance falls as humidity rises.
Why it works
This advice follows US Department of Energy guidance and the underlying principles of evaporation and latent heat.
Important exceptions
Safety, health, weather and the design of your home can change what is appropriate. Stop if an action makes conditions worse.
Related guides
Sources & evidence
Reviewed 2026-08-21
- US Department of Energy: Home cooling ↗
Supports: Fans, ventilation, evaporative cooling, air conditioning, shading and energy use.
official guidance · Accessed 2026-08-21