Compared with other electric heating, reverse-cycle air conditioners are cheap and efficient to run. Inverter air conditioners, unlike older-style models, can vary their heating or cooling output to correspond with room conditions. This is more energy-efficient than older models, which either operate at 100% of their capacity or they’re off.
The Australian standard allows manufacturers to fix the compressor speed at a certain ‘rated’ capacity. We think this is unrealistic, as an inverter air conditioner will never operate in such a fixed mode in real life. Our test method operates the air conditioners at maximum cooling and heating settings, and therefore differs from the one used by some manufacturers for the energy label tests, which is why the energy efficiency on the label and our results don't always match.
In this test, all the models performed close to their claimed cooling efficiency. But when it comes to heating, the Toshiba RAS-13SKVR-A / RAS-13SAVR-A, and both Fujitsu models had a significantly lower efficiency than the one given on their labels.
That doesn’t mean they're inefficient or poor performers — most of the tested models provide more than three kW of cooling or heating for each kW of electricity they use. The issue is that you should be able to rely on the energy label that reverse-cycle air conditioners must display to tell you their cooling and heating capacity and how energy-efficient they are. It’s an essential tool for you to compare models, but in CHOICE’s view the current tests manufacturers can put their models through don’t always show the whole picture.
Things to consider before you buy
Do you need an air conditioner? Before you spend big on an air con, try to make your home more energy-efficient — for example, by installing ceiling insulation, providing shading for windows, and draughtproofing windows and doors. At best, this will mean you can get by without an air conditioner for cooling (perhaps ceiling fans will do the job — we’re planning to bring you test results for those later this year). At worst, it means you can make do with a smaller model and run it less often.
Which type? Portable models, which are generally for cooling only, can be moved from room to room, and from house to house. But they’re usually only suitable to cool relatively small areas. CHOICE will be testing some portable models later this year. Window/wall units are comparatively cheap to buy, but generally not as efficient as and noisier than split systems, which consist of an outdoor unit that sits outside your home and contains all the noisy bits needed to condition the air, and — connected by a hose — an indoor unit (or several) that’s installed on a wall and blows the conditioned air into your room.
Efficiency: This tells you how many kilowatts (kW) of cooling or heating an air conditioner provides per kW of electricity it uses. The more efficient it is, the lower the running costs and greenhouse gas emissions.
Airflow: The air conditioner’s fan circulates the cooled or heated air around the room. Ideally, you want a model with a wide airflow range (and multiple fan speeds): from very high to help the room cool down or heat up quickly, to very low so there’s less noise and no unpleasant draught once you have the right temperature — especially if you’re using the air conditioner in your bedroom.
Noise: A noisy indoor unit may interfere with your conversation, radio, TV — or sleep. And most local councils have noise restrictions relating to the use of air conditioners: check before you buy, especially if the outdoor unit has to be installed close to your neighbour.