Posted by & filed under Keeping cool.

The major difference between evaporative and refrigerated air conditioning systems units comes in the way they cool air.

Refrigerated air conditioning involves taking hot air from inside a house, putting it outside, while bringing the cooler air from outside into the house, and cooling it further using refrigerants. As you can imagine, this takes a lot of energy!

Evaporative units, on the other hand, cool air by passing warm air through water. This Energy House blog post explains the process well:

“Hot air from the exterior enters the cooling unit located on the roof where is filtered and cooled. A pump in the system regularly circulates water from a reservoir on to a cooling pad, making it very wet. As the air passes through the moistened pad, it is cooled by evaporation and safely spread through your home.”

Other differences?

  • Well evaporative units cost far less than refrigerative units to install, run and maintain.
  • Refrigerative units operate better in humid climates.
  • Evaporative units are great for flushing air out of the house and bringing fresh air in. They’re also more environmentally friendly.
  • Refrigerative units tend to be able to get a house cooler in really hot weather.
  • Evaporative units are better for asthmatics because, as it notes here: The moist pads from an evaporative cooler are relatively efficient air filters, trapping some dust and pollen.
  • Refrigerative units can be reverse cycle (so they can cool as well as heat) where evaporative units cannot.

Which air conditioning unit should you buy for your home?

Well if you’re on a limited budget and you live in an area where the heat is fairly dry (ie Western Australia), then an evaporative unit will do the job for you.

If you live in more humid parts of Australia then you’re probably going to have to install refrigerative units (despite the extra costs of doing so) as, unfortunately, evaporative units will tend to exacerbate the humidity in your home, for very little cooling effect.