Air conditioners

In regional Queensland, our long hot summers can mean having an air conditioner is more of a necessity than a luxury. While air conditioners can be one of the bigger silent energy suckers in your home, follow our tips to help you to stop your aircon blowing your dough.

Energy sense tips

General

  1. Select the right temperature. Stick to 25oC in summer and 18oC in winter. Every one degree cooler in summer adds around 10%1 to the amount of electricity the aircon uses – which can quickly add up!
  2. Install the right sized aircon for the space you need to cool or heat. Consider factors such as the size of the room, the direction the windows in the room face and whether you have insulation in the ceiling.
  3. Choose an aircon with a high energy star rating - for every extra star your aircon has, you’ll save around 15%2 in running costs.
  4. Insulate your home by installing roof and wall insulation with a minimum R-value to suit your locality. In Queensland, this could range from R4.1 to R5.1 for the ceiling and around R2.8 for the walls3.
  5. Maintain your aircon regularly, particularly before the summer cooling and winter heating periods. Follow the manufacturer’s instructions to clean the air filters and coils.

Cooling

  1. Use fans to circulate cool air - they’ll help your aircon to distribute cool air to where it’s needed. Remember – fans cool people, not rooms, so turn them off if nobody’s there.
  2. Turn your aircon off when you’re out and wait until you’re back to turn it on again. It should only take around 20 minutes4 to cool your home when you return.
  3. Select the air recirculate setting when running your aircon. Otherwise you'll be drawing in much warmer air from the outside and using a lot of electricity to cool it down.
  4. Close doors and windows in areas you want to cool to help keep the cool air in and the hot air out.
  5. Consider using a fan instead. If the weather allows, open your home to create cross breezes and use ceiling fans to keep you cool. It’ll be much friendlier on your pocket too.

Heating

  1. Prevent heat loss by repairing faulty door seals.  Use door snakes and weather-strips to block any gaps where heat can escape.
  2. Focus your heating in commonly used rooms and trap in warm air by closing windows and doors.
  3. Rug up. Dress appropriately for the weather and check rooms for drafts.
Air conditioner calculator

About star ratings

The Energy Rating Labelling Scheme is a national program to support the development and supply of energy efficient appliances by providing clear and objective information.

This information is intended to help customers understand the energy requirements and running costs of different appliances and help them to choose an appliance which best meets their needs.

When buying a new air conditioner, check the energy rating label. These labels provide a comparative assessment of the appliance’s energy efficiency and typical annual energy usage (in kilowatt hours per year).

For more information on energy labelling visit the Energy Rating Label website. Here you’ll also find a handy Energy Rating Calculator where you can compare the consumption and running costs of various appliances by brand, star rating or energy consumption.

Types of air conditioners

If you’re looking to install a new air conditioner in your home or upgrade your old one, there are several types of air conditioning systems available.

Whichever you choose, you’ll need to ensure it’s the right size for the room and your household.

Split system air conditioners

All split system units have the compressor unit/s located separately from the air outlets and come in a variety of configurations, including standard single head units, multi-head units, ducted units or portable units.

With the compressor unit located separately, they are comparatively quieter than box air conditioners. However, the performance, energy efficiency, noise levels and temperature control capabilities of units in this category can vary significantly between brands and models.

Some models feature reverse-cycle functionality, which means the condenser component that expels hot air is located inside the header unit, rather than outside with the compressor.

Single head systems have one header unit to supply cooled air indoors, with a single compressor unit located outdoors. Models are available to mount on the floor, wall or within the ceiling.

Multi head units have more than one header unit connected to the same outdoor compressor unit.

Inverter systems can run at different capacities in response to the current ambient temperature of the space and can require less energy to maintain room temperature once it has been cooled. However, this also means they typically require more energy in the initial cooling phase.

Portable units are available; however these can be much less effective and comparatively very inefficient.

Ducted systems supply cooled air from an outdoor compressor unit to multiple rooms in the house through an integrated system of insulated ducts running through the roof space or under the floor. These units have the ability to cool the whole house with one system, but can be comparatively more expensive to install than multiple split systems and require more energy to run. Ducted systems are more easily and economically installed when building a new home or doing a major renovation.

Window box air conditioners

This style of air conditioner has all of its components in one unit, which can be mounted on a window frame, or for a more permanent installation, into an external wall.

They are generally cheaper to purchase than split systems. Their output capacity is lower than a comparatively sized split system, so they are best suited to cooling single rooms or other small areas. Having the condenser located with the unit means they can also be quite noisy.

Important information

1. Based on an ambient temperature of 30oC. Around 10% calculation based on comparison of running costs for aircons set at 25oC and other temperatures to 20oC. Refer to our online savings calculator. When the air conditioner is set at 25oC it will cycle on for 70% of time. On cycling will increase as the air conditioner temperature is lowered until when set at 20oC when the air conditioner will cycle on for 100% of the time. Results may vary depending on whether air conditioner is sized correctly for the room it is operating in, windows and doors are shut, blinds are closed and climatic conditions in your area etc.

2. Based on information provided in the energy rating program website on the comparison of running costs of products with different star ratings.

3. Source: Building Code of Australia 2010, Vol. 2.

4. If the air conditioner is functioning normally, is sized correctly for the room it is operating in, windows and doors are shut, blinds are closed, and the air conditioner is set to 25oC in summer and 18oC in winter etc, the air conditioner should only take about 20 minutes to cool or heat the room to the desired temperature.