Home cooling guide

Do you really need an air conditioner?
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01.Home cooling guide


Do you really need an air conditioner?

Before you buy an air conditioner (see our latest reviews of large and small air conditioners), see whether you can't manage to keep the heat entering your house in other ways. It may save you a big investment:

  • The first step is to insulate your ceiling (and walls if possible).
  • Shading for east, north and west-facing windows helps prevent the sun’s heat from entering your home; outside shading is more efficient than internal blinds or curtains.
  • Draughtproof your home.
  • Avoid activities that produce heat during the day.
  • Wear light clothing made from natural fibres.
  • Try fans for a cooling effect.
  • If you live in a hot and dry climate, an evaporative air cooler may be a cheaper alternative than an air conditioner.

Please note: this information was current as of April 2009 but is still a useful guide to today's market. 

Buying the right type

If you’ve decided an air conditioner is worth buying, you need to decide which type best meets your requirements. They come as:

  • portable units
  • wall or window units
  • split systems where the compressor is installed outside the house and the air outlet(s) inside,
  • ducted systems with an outside compressor and several ducts inside into as many rooms as you like.

There are cooling-only and reverse-cycle models. Reverse-cycle air conditioners usually only cost a little bit more than cooling-only ones of similar capacity, and provide very efficient electric heating.

Getting the right size is the next step. Use our cooling and heating capacity calculators to find out what you need.

Finally, compare the energy-efficiency rating of the models with the capacity you need. Air conditioners are very efficient. For every kW of electricity consumed, two or more kW of heating or cooling capacity can be produced. However, there are still differences between models.

Air conditioners must carry an energy rating label — the more stars a model has, the more efficient it is, and the lower its running costs. An efficient system can save you hundreds of dollars in running costs each year compared to a less efficient one.

Portable units

Portable air conditioners use the same heat-exchange principle as built-in models. So they can cool and dehumidify the air. As they’re not installed to a wall or window, you can move them around from room to room — for example, use them in your living room during the day, and in your bedroom at night.
However, some are only suitable as spot or personal coolers. For a similar price, you can get an installed window/wall or even split-system air conditioner, which will give you better performance.


Reverse-cycle split-system air conditioners (around 6 kW): We tested seven models suitable for a large open-plan living area.

Ducted systems

Ducted reverse-cycle air-conditioning can be a very convenient way of cooling and heating your home.
A ducted air conditioner consists mainly of a heat pump (1), ducting (2), vents (3) and a return air vent (4).

With a central cooling or heating system, the right size and design depend on a range of parameters, such as your home’s floor plan, the size and orientation of windows or level of insulation. The system has to be designed by your installer for your individual situation, and shouldn’t be bought “off-the-shelf”.

For more details on ducted air conditioners and other central heating and cooling systems, see our article Ducted air conditioning.



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