Efficient cooling? Choose a reverse cycle split system! – AEF | Australian Energy Foundation

Efficient cooling? Choose a reverse cycle split system!

The recent hot summer days mean that many of us are trying to get some respite in a cool air conditioned space. Steadily hot days mean that whatever cooling you may be running could be costing you a lot in energy bills, especially if the air conditioner you have is old or has not been maintained regularly.

So why is a reverse cycle air conditioner (RCAC) split system the most efficient method of cooling (and heating!)?

A reverse cycle air conditioner is valued for its ability to both cool and heat an entire house. Each system consists of two parts: an outdoor unit and indoor unit.

The outdoor unit of a RCAC extracts heat from indoors and moves it outdoors via pipes containing refrigerant gas, which cools the house – this is known as heat pump technology.

You already have a heat pump in your home – a refrigerator! It transfers heat from inside the fridge to the outside (hence why the exterior of a fridge can feel warm). An air conditioner uses the same method to cool your house in summer.

The efficiency of this technology is down to the fact that an RCAC is moving heat/cool air in or out of your home vs other options which are creating heat or cool air through a heating element, fuel source or water. Each unit of electricity can generate between 3-6 units of cooling (or heating), in comparison to other options which rarely produce more than one unit of heat/cooling per unit of electricity.

Key principles of efficient cooling

The key principles of efficient cooling, in order of priority are:

  1. use fans first
  2. only cool the room you’re using
  3. set the temp to no lower than 24-26 degrees*

Believe it or not, your body will regulate itself during the winter months, in order to maintain thermal comfort, and it will then adapt gradually to the hotter temperatures as they increase over the summer months. Therefore, your ability to handle hot days does improve through the course of the summer.

This means that, when it’s warmer but not too hot, you don’t need to blast your RCAC at the lowest temperature. Although it may seem counter-intuitive, when its only be 26-30 degrees outside, run your RCAC at 24 degrees. As it heats up to 31-40 gradually raise the temperature on your AC to 26-27 degrees, as your body adjusts to the hotter weather.

Given that every degree cooler corresponds to approximately a 10% increase in running costs, it’s in your interests to start small and gradually increase the setting. The above example also means that your RCAC is not working in overdrive and draining power to do so.

if you need to lower the temp., do so as your health and comfort is first priority.


With the possibility of more hot days to come, think back to when you last maintained your air conditioner unit or had it checked. How old is it? Might it be working so inefficiently that it needs replacing?

With energy bills rising, it’s worth getting out your instruction manual and checking the maintenance schedule. Remove the filter and clean it according to the instructions or book a service with an HVAC professional. If your unit is more than 15 years old, replacing it with a more efficient model may mean you feel more relaxed about switching it on during a really hot day.

Having an efficient cooling appliance such as a reverse cycle split system can efficiently use power to keep you cool.  You can also use it for heating in winter!

There hasn’t been a better time to assess your cooling appliances and consider whether you need a new reverse cycle air conditioner. The Shire’s bulk buy program gives you access to discounted products installed by quality installers. The program’s vetted installer is also offering a free service with any new purchase of a RCAC until the end of February 2022. T&Cs apply. To get a quote, go to the bulk buy website and submit a quote request.

For further information on how to choose a reverse cycle air conditioner, read our comprehensive guide on Choosing a Home Air Conditioner or call one of AEF’s advisors for free advice – 1300 23 68 55

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