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What size air conditioner do I need?

When looking at all the air conditioners on the market these days, we understand it can be a little bit of an overwhelming task to figure out which is best for your needs. Large, portable, small, reverse-cycle, window. split-system, multi-system... the list goes on.

Air Conditioner

That's why we have put together a little bit of information regarding one of the first things you must get right when choosing an aircon - size. Ensuring you choose an air conditioning system that is the correct size for your room or space is crucial for so many reasons, so keep reading if you'd like to know a little more!

If you have any questions, feel free to give Hanson Electrical a call on 0456 478 029 and we would be more than happy to help.

Air conditioning factors to consider

Firstly, let's take a look at the factors to consider when deciding the best size of aircon for your needs:

  • Room size: How large (or small) is the area you are trying to cool? Are you looking at cooling one room, or a whole home?
  • Room type: Does the room have a lot of traffic? Is it a bedroom, study, kitchen or other area?
  • Usage: How often will you be using the system? Will it be on every day, or only used occasionally?
  • Capabilities: What do you require your system to do? Do you need reverse-cycle and were you considering ducting?
  • Energy efficiency: What size system is the most energy efficient for your space?
  • Upfront cost: What are the different purchase and installation costs associated with each system?
  • Running costs: What are the ongoing running costs for the different-sized systems?

This list is in no way exhaustive, however it covers a lot of the major aspects to think about when looking at the best system size for your space.

What size air conditioner is right for you? Talk to our electricians today and see how we can help you.

How do I calculate what size air conditioner I need?

This can be a pretty tricky question to answer, if you don't know what to look for... which is why we have put together the below table to help you out.

Room Size

Example m²

Room Examples

Capacity kW

9-25 square metres

3.0m x 3.0m = 9m²

5.0m x 5.0m = 25m²

Small kitchen, small lounge, bedroom, study, small office


25-35 square metres

5.0m x 5.0m = 25m²

5.5m x 5.5m = 30m²

Small lounge, mid-sized kitchen, small room with a high ceiling, bedroom, office


35 - 45 square metres

6.3m x 6.3m = 40m²

6.7m x 6.7m = 45m²

Bedroom with ensuite, large bedroom, mid-sized lounge

5kW - 6kW

45 - 60 square metres

6.7m x 6.7m = 45m²

7.1m x 7.1m = 50m²

7.7m x 7.7m = 55m²

Large lounge, large open plan area, small shop, office

6kW - 8kW

There are air conditioning systems that are commercial-sized that run at 9.0kW or higher, however these kinds of systems are not installed by everyone. Speak to your local professional as to whether they can assist in this regard.

How much will an aircon of that size cost?

The cost of aircons can vary depending on a lot of things, however the following is a look at average air conditioning system purchase costs.

Kilowatt Capacity

Average Price


$500 to $1,000


$750 to $1,500


$1,000 to $1,800


$1,500 to $2,000

What about running costs?

According to Canstar Blue , Australian households spend around $240 a month on electricity when summer comes around. Although people believe that aircons are money burners, a lot of the time the energy costs of running an air conditioner are quite low:

  • A split system aircon, or a window unit, can cost around 11-16c an hour for a 12m² room, 38-54c an hour for a 36m² room and 53-75c an hour for a 50m² room.
  • A ducted system for a whole home (around 200m²) can cost around $2.26 - $2.67 per hour for energy.

Why is a correct-sized air conditioner so important?

Ensuring you have an aircon that is the correct size for your space doesn't just save you money, it also helps with energy efficiency and ensures the best system for the environment. In addition to all this, choosing an air conditioner that is the right size for an area will ensure you stay comfortable, no matter the weather outside... which is exactly what you purchased it for!

Hanson Electrical

Your local aircon experts

If you have any questions regarding the best air conditioner for your home or business, or would like to speak to one of our knowledge team members regarding an aircon issue or installation, give Hanson Electrical a call on 0456 478 029 now. We are experts when it comes to determining the best air conditioning system for your needs, so get in contact today!


Energy Rating (Air Conditioners):

Canstar Blue (A guide to air con sizes and costs):

Hanson Electrical (Air Conditioning Brisbane)

All information contained on this page is a general guide only and should be taken as such. You must complete your own research and decide what system is best suited to your needs.

What size air conditioner do I need? Talk to our electricians today and see how we can help you.

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