04.What to look for
Size/capacity - To get the most from an air conditioner, match its cooling (and, if required, heating) capacity to your room. Use the CHOICE cooling and heating calculators to determine the right size for your home.
Energy efficiency - Once you’ve worked out what capacity you need, compare the star ratings of models of similar capacity — the more stars the better. Note that star ratings are different for heating and cooling — see the picture and caption, below, for more on this.
Automatic de-icing - If you live in a cold area, frost may build up on the outdoor heat exchanger coils in winter if the air conditioner doesn’t have this function (all the tested ones do).
There are two types of energy efficiency label for reverse cycle air conditioners. The star rating for heating always refers to heating at 7°C outdoor temperature and cooling at 35°C. The ‘all options’ label pictured also lists the product’s heating capacity at 2°C outdoor temperature. The higher the number of stars, the more efficient the model (efficiency is calculated by dividing the output capacity by the input power).
Larger capacity models (more than 2.4 kW of input power) can’t be plugged into a normal power point but need a special connection.
Variable output compressor: ‘no’ means conventional (on or off), ‘yes’ means inverter.
Unless it’s stated otherwise, all the air conditioners tested have the following features:
- A timer lets you switch the air conditioner on and/or off automatically at certain times.
- All the tested models have one, but they are not always as good as they should be. Ideally it should indicate status and settings at all times. It’s difficult to see the settings on the Airwell and Carrier. All of the models (except the Mistral) have a real time clock which makes it easy to set on/off times.
- Most models (except the Mitsubishi Electric and Panasonic) also have a sleep or a ‘one-hour-off’ timer.
- Remote control.
- Operating modes
Auto - Automatically chooses the mode required to keep the room at the chosen temperature.
Cool - Pumps heat from the inside to the outside.
Heat - Pumps heat from the outside to the inside.
Dry - Dehumidifies the air (while cooling only slightly).
Fan only Blows air without heating, cooling or drying. This can be useful when it’s not hot enough to justify running the air conditioner and all you want is a bit of a cooling breeze. In our test, all except the Fujitsu, Panasonic and Mitsubishi Electric have this function.
- Some models have settings with reduced noise (quiet operation) and/or extra-high power (fast or jet operation). See Results table.
- A sleep mode adjusts the temperature in several steps (up when cooling, down when heating) so the air conditioner doesn’t have to work as hard — or as loudly — when you’re sleeping. You can set the sleep mode for as long as you like. See the table for which models have this feature.
Adjustable louvres allow the air to be distributed more evenly — point them up for cool air and down for warm. All models in this test let you do this with the remote control, and they have auto-swing. You can also manually adjust the vertical louvres on the Haier and horizontal louvres on the Airwell, Carrier, Haier, Mistral and Toshiba; on the rest you adjust them with the remote control which is the better option.
Restart delay This protective feature prevents the air conditioners from starting up again too soon after being switched off.
Other ways to keep cool
Before you fork out for a large air conditioner to keep the approaching summer heat at bay, consider all the other options that might cool you down sufficiently without costing the earth — insulating your home, shading and draught-proofing doors and windows, installing blinds, curtains or awnings, planting deciduous trees outside windows or glass doors, and, perhaps, reducing your air conditioner use in the car — they say if you’re less used to being cool in the car, you’re less likely to demand it at home.
We've previously reported on two other cooling options. Ceiling fans use up far less energy than air conditioners and make you feel cooler without reducing the room temperature. A portable air conditioner lets you cool one room at a time, but it’s clunky, hard to operate and not particularly energy-efficient.
If you must buy a large air conditioner for those scorching days where temperatures are sky-rocketing, choose one that’s just as efficient at keeping you warm next winter.
When it’s cold outside
In many areas of Australia, winter evenings can get much colder than 7ºC, which is the outdoor temperature we used in the past to test the air conditioners’ heating efficiency, in line with the tests for the energy label. So this year we decided to conduct our tests at the lower outdoor temperature of 2ºC — also according to the standard — to see how the different models cope with these tougher conditions.
As could be expected, the air conditioners were generally less efficient at the lower outdoor temperature than at 7ºC. At 2ºC the heat exchange coils in an outdoor unit tend to frost up, so the air conditioner has to defrost them before indoor heating can resume.
These defrost cycles generally lower the units’ claimed heating capacity by up to about 30% and their claimed efficiency by about a quarter to a third. The Mitsubishi Heavy Industries SRK63 was the most efficient at heating; three others (see results table ) scored above 70% for heating efficiency — one of these models would be best if you live in a cold area.
Factors to consider
Split systems consist of an outdoor unit that sits outside your home and contains all the noisy bits needed to condition the air, plus an indoor unit (or several) that’s connected by a hose and installed on a wall to blow the conditioned air into your room. They’re more efficient and less noisy than cheaper, window/wall units.
Inverter air conditioners, like the ones in this test, can vary their heating or cooling output to correspond to room conditions. This is more energy-efficient than older models, which essentially have two settings: 100% of their capacity or ‘off’.
Efficiency - This tells you how many kilowatts (kW) of cooling or heating an air conditioner provides per kW of electricity it uses. The more stars on the energy label, the more efficient it is and the lower the running costs and greenhouse gas emissions.
Of the models on test, Mitsubishi Heavy Industries SRK71 had the best cooling efficiency at part load, whereas the Mitsubishi Heavy Industries SRK63 had the best cooling efficiency at full load, making these two models the best for cooling overall. See How we tested for a description of full and part load testing. The next best for cooling efficiency were the Fujitsu and Airwell. The best for heating efficiency were the Mitsubishi Heavy Industries SRK63 and the Panasonic.
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 (multiple fan speeds): from very high to help the room cool down quickly, to very low so there’s less noise and no unpleasant draught once you have the right temperature. Our tests found both Mitsubishi Heavy Industries models and the Mitsubishi Electric have the best combination of high and low fan settings. The Mitsubishi Heavy Industries SRK63 has the most powerful maximum fan setting, which helps cool or heat a room quickly. These three models also have a ‘low fan’ setting with comparatively little airflow, so you’re more likely to find a setting that doesn’t feel like you’re sitting in a wind tunnel, while still moving some air about.
Noise - A noisy indoor unit may interfere with your conversation, entertainment 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. We tested the noise in the air conditioners’ quietest modes and found most models to be similarly quiet, apart from the Mistral which was noisy both indoors and outdoors.
Ease of use - The Mitsubishi Electric scored very well for ease of use; the Haier ranked lower than the rest. There’s not much difference between the rest.