What size aircon do I need?

When summer hits in Australia, depending on where you live, your home might feel like a sauna. Having cool air at just the right temperature can be the key to beating those sweltering days.

However, when you’re in the market for a new air conditioner, it’s important to select the right size unit for the space, to save money, reduce your energy consumption and have a system that maintains its peak performance.

While the size or capacity of the unit may seem like the most significant point of consideration for effective cooling; the climate you live in, how well your home is insulated, and the orientation of your room can play a larger part in calculating the best size air conditioner for your needs.

Ensure you do your research first, so you choose the right air conditioner size with the ability to keep the temperature comfortable without resulting in a hefty power bill. Read on to discover what size air conditioner will suit your home, how much it might cost, how to use an air conditioner size calculator or chart, and the different sizes or capacities by system type.

What determines the size air conditioner I need?

There are many factors that affect the size of the air conditioner you’ll need to have ideal cooling in your home. As mentioned before, these include:

• Your room size: Calculate the entire volume of the room, not just the floor area.
• The insulation in your home: Are your walls, floors, and ceiling well insulated to prevent heat transfer?
• Your location: In warmer climates you’ll need an air con with more power than in cooler parts of Australia.
• The direction the room faces: Is the orientation of the room north-facing or south-facing? If it’s facing southwardly, your room will be naturally cooler, and your ac capacity can be smaller as a result.

Before you consider installing an air conditioning unit in your home, it’s a good idea to ensure you have a quality roof or ceiling insulation installed. This can save a lot of money in the long run on expensive heating and cooling bills and means you can get a smaller and more affordable ac unit. A more powerful air conditioner is not always the answer to efficient cooling in your home.

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How do I calculate what size air conditioner I need?

If you’re wondering “what size air conditioner do I need?” you can find an online calculator or sizing chart to help you plan and select the best option. Be aware that if you use an air conditioner size calculator, some generic guides will advise for air conditioners with a higher capacity than you might need, so don’t solely rely on their recommendations.

If you’re using an online air conditioning calculator, choose a version that estimates your needs based on all the relevant factors, including:

• Your climate
• The insulation rating in the ceilings and walls
• The type of dwelling and materials used
• The height of your ceiling
• Whether your house is single or multi-storey
• Window size and orientation
• Window coverings
• Shading, etc.

We recommend selecting a model that has a capacity just a touch more than you’ll need for the room. For instance, if you’re room size requires a 5kW air conditioner, you can opt for an ac unit in the 5 to 5.5kW cooling capacity range.

If you choose a unit that has too high a capacity, this can cause it to run frequent short cycles to keep the temperature at the right level. This is not optimal as it will lead to higher power bills and more energy consumption, an irregular air temperature, ineffective dehumidifying, and potential errors and issues with the unit.

If you buy a unit that’s too small for the room, it will be working in overdrive to try to achieve the desired cooling level. This will also increase the power used, create drier air and cause problems for the unit.

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What size air conditioner do I need for my house?

Calculating the size of the air conditioner you need for your home can be tricky. If your air conditioning unit’s capacity is too small, it will struggle to cool your house and if it’s too large you may end up having a problem with being either too cold or too hot.

The right size air conditioner you need for your house is dependent on the size of your house, the level of insulation in your home and your location.

For an open plan area or large lounge, you might need a 5 to 9kW air conditioner capacity, which can cost between $1,000 and upwards of $5,000.

What size air conditioner do I need for my room?

Each room in your house will have a different capacity requirement for cooling. A rough indication of the size your need is 0.12 to 0.15kW of power per square metre of floor area. This only accounts for the room’s length and width in metres and does not include other factors such as ceiling height.

Air conditioner room size calculator

An air conditioner for a small room no larger than 20 square metres, such as a bedroom or a study, would usually need a capacity between 2 to 2.5 kilowatts. However, in cooler climates like Tasmania, it could be much less. Bedroom air conditioners of this size are usually priced between $600 to $2,800, depending on the brand you purchase and its specifications.

For a medium-sized bedroom that might have an ensuite or a small lounge room between 20 and 40 square metres in size, you would need a 2.5kW air conditioner up to a 5kW air conditioner unit to sufficiently cool the space. This can cost anywhere from $750 to $3,200.

A large bedroom, large kitchen, or medium-sized lounge area, between 40 and 60 square metres, requires an ac capacity of 4 to 6 kilowatts. You can expect to pay anywhere from $1,000 to $4,000.

What size split system or ducted aircon do I need?

Although both cooling systems have roughly the same cooling capacity range, the running costs associated with split systems and ducted aircon differ. If you want to cool your entire house or larger open plan spaces, then ducted cooling will be a more economical choice.

What size split system do I need?

As noted above, when looking for a split system air conditioner sizing calculator, find one that allows you to add extra details about the dimensions of your home, climate influences and so on. A 2.5kW split system would suit a room size of up to 25 square metres of floor area, and an 8kW split system would efficiently cool a room between 47 and 80 square metres of floor area.

What size ducted aircon do I need?

If you want to have multiple rooms in your home cooled, it makes sense to go with a ducted air conditioning installation with zoned areas.

If you need a ducted air conditioning size calculator or guide, then simply decide on the number of rooms you will need cooled at the same time. Calculate the total volume of those rooms combined to know what capacity ac unit you’ll need installed in your home.

It’s best to get quotes and advice from a reputable air conditioner installer in your area.

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What size portable air conditioners is best?

If you’re considering investing in a portable air conditioner for a small room, you’ll still need it to have an output of 0.15kW of power per square metre. A portable ac is easy to install – just plug it in and move it around where you need it in your house.

What size window air conditioner do I need?

Window air conditioners are ideal for small to medium rooms up to 36 square metres of floor space, such as bedrooms or a home office. They can be mounted in a window and in some cases, they are installed directly into a wall. You’ll need a unit with about 1 to 1.5kW of power for every ten square metres to sufficiently cool the room.

Get air conditioning quotes

Before you choose an air conditioner for your home, get in touch with local air conditioning installers for advice and a free quote. With Yellow Pages you can get multiple quotes and compare them to make the right decision on your investment. This is the best way to get a good idea of air conditioning installation costs in your area.

* All costs and prices quoted were sourced at the time this cost guide was written and should only be used as an estimate.