Reverse Cycle Air Conditioning vs Evaporative Cooling

The purpose of today's article is discuss the differences and pro's and con's of two of Australia's most popular cooling systems. Evaporative cooling and reverse cycle air conditioning are two very different methods of cooling your home each with their benefits and drawbacks.

What is evaporative cooling?

Here we're referring to a roof mounted system that relies on water to cool. With evaporative cooling, you're taking air from outside the home and increasing the humidity, which has a cooling effect, and delivering that through and out the home. This gives a cycle of fresh air in and out, as opposed to recycling the same air through the house.

What is a reverse cycle air conditioner?

The reverse cycle air conditioning process uses a compressor outside and a fan coil inside where cooling or heating refrigerant passes through depending on the setting it's on. Air taken from the inside of the house is then passed across the heating/cooling fans and back into the home. So it's like a fridge, you put your hand in there and you can feel the cold, and like the fridge you can feel every object in your house going cold. The key difference in understanding the technologies then is you are locking conditioned air in with a reverse cycle system, passing it through the coil again to continue cooling. It's a cycle that keeps taking the same air back in across the fan coil and delivering it back to the house. Each time it passes through the fan coil it keeps getting cooler and keeps delivering that to your home.

It's important to note that a reverse cycle system can be in the form of split systems on the wall or a fully ducted system in the roof.

Reverse Cycle

Pro's

works in all weather conditions. dry, humid, freezing and hot.
effectively removes humidity from a room for that crisp feel
very effective air filtration systems capable of removing dust, pollen, odours and bacteria
ability to cool and heat your home from one unit
newer models are very energy efficient

Con's

higher running costs than an evaporative system
higher installation costs for ducted systems
filters need to be cleaned or replaced regularly to maintain effectiveness
doors and windows need to be kept closed for maximum cooling

Evaporative

Pro's

very economical to run
slightly cheaper setup costs
simple, compact installation
ensures a constant supply of fresh, cooled air throughout your home
filter pads trap some dust and pollen

Con's

doesn't not perform well in humid conditions, sometimes making it even more 'muggy'
very little temperature control as you can only control the fan speed.
basic air filter system only, many airborne irritants or odours missed
not ideal for those with asthma or respiratory issues
possible risk of water leakage from ceiling outlets unless fitted with covers
can not heat the room and you would need a different source of heat

Conclusion

Almost all new homes will opt for a reverse cycle system, which could be fully ducted or split. Evaporative systems are more commonly found in large workshops that keep their doors and windows open and the system provides a nice, cooling breeze. They are found less and less in new homes.