What size air conditioner do I need?

What size air conditioner do I need?

An aircon system can be a costly, long-term investment. It is important to take the time to choose the right unit. You will need the right size unit for your room. This is dependent on the space, insulation, orientation and location. It is crucial to make the right decision now in order to maximize the unit’s performance and minimize running costs.

How can you decide which size unit is right for you? Let’s talk about it.

Room Size

It is easy to measure the room’s length and width, but it can be difficult to calculate the volume of the room. To get an accurate idea of how much cooling power is required, you will need to know the heights of the ceilings.

This is an approximate guideline for the size of the air conditioner you will need to cool a specific room:

Room Size


Capacity: Capacity:
Smaller (up to 20m2)Study or bedroom2-2.5kW
Medium (20-40m2)Bedroom w/ensuite, small lounge room2.5-5 kW
Large (40-60m2)Large bedroom or medium-sized lounge room4-6kW
Extra Large (60+m2)Large lounge areas and open plan areas are great for entertaining.6-9 kW

This guide will help you get an idea of what works well in your space. You shouldn’t make the mistake of going too small in order to save money, or too large to keep your space looking like an igloo. This can end up costing you more money over time. A poorly sized unit can increase your power consumption and cause more wear on the unit.


The size of the air conditioner unit that you require will depend on where you live in Australia. A room in Darwin, for example, will require a larger unit than a similar size in Hobart. A 2.2kW unit is usually required for a room of 30m2 in Brisbane.


Is the ceiling and wall insulation adequate? When it comes to creating a home that is thermally efficient, ceiling insulation is a key factor. We recommend installing ceiling insulation if your ceiling is not already insulated. You will be able to install a smaller unit, and your ongoing operating costs will be lower. This will save you money over the long term.

How much sunlight does your property get?

You should also consider the orientation of your room and how much sun it receives throughout the day. Large windows facing the west or north can allow in lots of summer heat, while south-facing windows will keep the room cooler. Pre-cooling can lower the cost of an air conditioner in a room facing north or west. However, a larger unit might be required to cool the room efficiently.

For expert advice, speak with our friendly team!

We at All Kind Air & Electrical understand that choosing the right air conditioner for your home or business is not an easy task. Contact our friendly team to help you choose the right size conditioner for your home.

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