When considering purchasing a new air conditioner, the most important initial step is to ensure you select a suitably sized unit. Unlike other products such as televisions, where the size of the product is obvious, air conditioners typically look similar despite having wide ranges of heating and/or cooling capacities. Sizing for air conditioners is provided as a kilowatt (kW) capacity output figure (not to be confused with the power input, which is the amount of power required to produce the listed cooling and/or heating output) and you can find this on the energy rating label, as well as on the manufacturer’s product literature.

There are many different elements within your home that will impact on the size air conditioner you’ll require. These include (but are not limited to):

  • Whether you are looking to heat/cool a single room, a larger space or your entire home;
  • Size of room/home (including ceiling height);
  • External wall materials;
  • Insulation levels; and
  • How many windows you have, their glazing, shading and orientation.

Because of all these factors, it’s best to have a professional advise you on the size air conditioner to look for. There are also free online tools you can use to give yourself a rough idea.

Another element to consider is where you live. If you live in a cool climate, or where in winter temperatures are regularly below 5 degrees Celsius, it’s important that the unit you choose is able to cope in these conditions. Some models’ capacity will reduce at these times so you may find it unable to heat your space sufficiently, while others are able to continue to meet or exceed their capacity. Some manufacturers will test their products at a colder temperature and provide the capacity output for 2 degrees Celsius. This information isn’t always easy to find though, so check with your retailer or installer to see if they can assist.

Undersized units will have to work harder to heat or cool your room, and may be unable to reach and maintain your preferred temperature. Oversized products will typically be less energy efficient and they’re likely to cost more upfront as well.

Ensuring the product you have selected is an appropriate size will mean you’ll remain comfortable in your home and not use more energy than necessary.