A guide to air conditioner sizes


Air conditioners come in many sizes, However, unlike some other products such as televisions or computers, where the size of the product is obvious, air conditioners may look similar despite their different capacities.

Air conditioner sizes are represented by their kilowatt (kW) capacity output figures. This is different from the power input, which refers to the power needed to produce the listed cooling and heating output.

When buying an air conditioner, it is important to get one that suits the size of your room. If the unit is too big, it will not be as energy efficient when cooling or heating the room. On the other hand, undersized units may overwork and struggle to even reach the preferred temperature.

So, how do you know what size of air conditioner you need?

Firstly, you need to have the size of your room at hand. If you have extra high ceilings you may need to factor in ceiling height, but generally, just the floor space measurement is enough.

The basic rule is to have a minimum 1 to 1.5kW of cooling capacity per 10 sq m of space. For smaller rooms of 20 sq m or less, air conditioners with a cooling capacity of 2 to 2.5kW should be sufficient. For areas that are 40 sq m or larger, we recommend larger capacities from 4kW and above.


Besides the size of the room, there are other factors that also need to be considered when choosing an air conditioner:

The type of room

Consider how your room functions – is it a living room, an open-plan living area and kitchen, a bedroom, or a study? Knowing how often the room is used and how many people are usually in it will also help you determine the air conditioner size that you need. For example, there may only be one person in the study at any one time, compared to the living room that usually holds the entire family. In this case, even if both rooms are of the same size, you may need a larger air con unit for the living room.

The level of insulation

Take note of the insulation of the floor, ceiling and walls. In summer, a room that is well insulated will be able to keep the heat out and the cool air inside for much longer. This means a smaller air conditioner may work much better and more efficiently in an insulated room, compared to an un-insulated room.


The size and orientation of windows as well as glass doors in the room can affect your air conditioner choice. Are the windows particularly large? Are the glass doors frequently opened? Also, windows that face north or west can let in a lot of heat during the hotter months, which means a larger capacity air conditioner may be needed.

The climate

The geographical location of your home will have to be considered too. For example, houses in Tasmania and Victoria will have not have the same requirements as those in the Northern Territory, due to differences in weather and climate.

Split systems for every home

At Total Electrics and Air-Conditioning, we have a wide range of air conditioning systems to suit different needs and requirements, including LG split systems:


LG Premium series

  • Active energy control
  • Wi-Fi Smart control
  • Plasmaster ioniser
  • Micro dust filter
  • Plasmaster auto cleaning
  • Outdoor quiet mode
  • 4-way swing
  • Jet cool

To select the best air conditioning unit for your home, get in touch with our team today. Our specialists will assess your home before giving you expert recommendations, so that you can make the right choice. Contact us at 03 9729 0894.