Enter the wet bulb temperature, dry bulb temperature, and the actual change in temperature of the swamp cooler to calculate the efficiency.

Swamp Cooler Efficiency Formula

The following formula is used to calculate the efficiency of a swamp cooler.

E =   ΔT / (Db-Dw) 
  • Where E is the efficiency
  • Db is the dry bulb temperature
  • Dw is the wet bulb temperature
  • ΔT is the change in temperature

To calculate the swamp cooler efficiency, subtract the dry bulb temperature from the wet bulb temperature, and then divide the actual change in temperature by that value.

What is a swamp cooler?


A swamp cooler is a type of air conditioning unit that cools air by adding moisture to the air. Swamp coolers are often known as evaporative cooling devices.

How to calculate swamp cooling efficiency?

Example Problem:

The following example outlines how to calculate the swamp cooler efficiency.

First, determine the wet bulb temperature. In this example, the wet bulb temperature is 30F.

Next, determine the dry bulb temperature. In this case, the dry bulb temperature is 50F.

Next, determine the change in temperature achieved by the cooler. The overall change in temperature is measured to be 10F.

Finally, calculate the efficiency of the swamp cooler using the formula above:

E = ΔT / (Db-Dw)

E = 10 / (50-30)

E = .50 = 50%