hand adjusting temperature on air conditioner picture

What Size Split System Do I Need?

When you want climate control in one or two rooms of your home, a split system air conditioner is an ideal choice. But before buying your air conditioner your next question has to be: What size split system do I need for my space?

Getting the size of the split system right is crucial. A unit that is too big for an area will waste power, while a unit that is too small for the room size will struggle to heat or cool your room and also add to your power bills.

Everyone’s situation is different, so let’s examine what split systems are, how they work and how to choose the right size unit for your home space.

Small vs Large Split System Air Conditioners

A split system air conditioner is a heating and cooling unit that has an internal unit and an external unit. The outdoor part is also known as the condenser or compressor, while the internal section is the wall-mounted unit that delivers the heated or cooled air.

When thinking about the size of the split system air conditioner you need, the reference is to the power of the unit, not its actual size. The power of split system air conditioners is measured in kilowatts (kW).

To calculate what size split system air conditioner, you need is a matter of measuring the space (or spaces) you plan to heat or cool.

The first step is to measure the floor space you are going to be heating or cooling. Measure the length and width and then multiply them to get square metres (m²). For example, if your area is 5m x 6m, the result will be 30m².

After measuring the floor space in square metres, the next step is to measure the ceiling height of the room. The watts (unit of power) will vary depending on the ceiling height of the room. Take your figures to a heating and cooling professional who can then accurately calculate the power you need.

You can also use the following rough guide:

  • 20m² or smaller (room size) – 2-2.5kW
  • 20-40m² – 2.5-5kW
  • 40-60m² – 4-6kW
  • 60m² or bigger – 5-9kW

If you want to cool or heat more than one area (such as an open kitchen near the main living space), you have to add that extra space onto your calculations. When it comes to heating or cooling multiple rooms it would be better to get a second indoor unit and hook it up to the outside compressor.

Don’t forget that well-insulated rooms take less power to heat and cool and will retain your desired temperature for longer.

Why Does the Size of Split System Matter?

The air conditioner size matters a lot, and here’s why: getting the right size ensures that your system runs efficiently and keeps your home comfortable.

First, if your split system air conditioning unit is too small, it won’t be able to cool or heat your space effectively. It will have to work harder and run longer, which not only consumes more energy but also wears out the unit faster. The heating and cooling capacity will also be reduced. You’ll find it struggling to maintain the desired temperature, leading to discomfort.

On the other hand, if your split system is too big, it will cool or heat your room quickly, but it won’t run long enough to properly dehumidify the air. An oversized air conditioner can leave you with a damp, clammy feeling indoors, and it’s not good for your indoor air quality either.

So, finding the right size split system is like Goldilocks finding the perfect porridge – it needs to be just right.

A professional heating, ventilation and air conditioning (HVAC) technician can help you determine the ideal size for split systems, matching them with your home based on factors like square footage, insulation, and climate.

Investing in the right air conditioner size not only saves you money on energy bills but also ensures you enjoy a consistently comfortable living environment.

Where Do I Install My Split System?

When you’re considering where to place your indoor wall-mounted unit (or units), the best position is high on the wall so cool air can flow downwards, which helps with the efficiency of the system.

The outdoor unit should ideally be located on a north or south facing wall, so it never faces the sun. If the unit does face the sun it is forced to work harder in summer, reducing its energy efficiency.

Take into account windows and doors when positioning your indoor unit, because cold draughts, warm air and sunlight will have an impact on your heating and cooling.

The Advantages of Split System Air Conditioning

While there are a number of choices in heating and cooling systems, there are many good reasons why split system air conditioning is the most popular choice for Australian homes.

Most households only need one or two living spaces heated and cooled, making a split system air conditioning system ideal.

Split system air conditioners are versatile and have a number of other advantages, including:

  1. Heating and cooling – a split system reverse cycle air conditioner is effective in any season.
  2. Easy to maintain – with one outer unit and one or more indoor units, a split system doesn’t have a lot of working parts and is easy to maintain.
  3. Heat or cool more than one roomMulti-head split systems allow for several internal units in different rooms to be connected to the one compressor and they can all run independently.
  4. It can power a ducted system – a split system can be hooked up with ducted heating and cooling if desired.
  5. Cost effective to install – unlike various other systems, a split system air conditioning unit doesn’t have high upfront costs.
  6. Suited to any home – a split system air conditioner can be installed in virtually any kind of home, unlike some other kinds of systems.
  7. Energy efficient – Split systems use less electricity than other climate control options, reducing your running costs.
  8. Improves air quality – Split system air conditioning filters the air and removes harmful contaminants and allergens.

Making the Right Choice

So, what size split system do you need? When you know the size of the space and number of the areas you want to heat or cool, you can choose the right size air conditioner for your home.

Speak with a heating and cooling specialist from Metropolitan Air Conditioning to work out the correct split system power for your space and arrange for professional installation.

Please note: This information is provided for advice purposes only. Regulations differ from state to state, so please consult your local authorities or an industry professional before proceeding with any work. See our Terms & Conditions here.

Published: 2022-10-13

Air Conditioning Specialists You Can Trust

Our Promise Going Further

Our specialists pride themselves with honest reliable services


Our fixed pricing structure guarantees transparency. You will always be quoted the complete costs before work can commence, and our expert technicians will guide you through the process.

Our specialists pride themselves with honest reliable services


Not all jobs are created equal, but all jobs are equally important. Whether it's a simple repair or ducted air conditioning install, we apply the same high levels of dedication and service no matter the scope of the work.

Professional Expert Technicians


Home is your castle. Your pride and joy. Our well-spoken technicians will show respect towards you and your property and always clean up after themselves.

Technician Zip Pay Payment Options Image
Technician Zip Pay Payment Options Image

Now Available!

Interest free Air Con with trusted pay later options

What Our Happy Customers Have to Say

Better service starts here

5 stars rating

I called them in the morning, and they were at my doorstep within a few hours. The technician was quick to identify the problem, had the necessary parts, and repaired my AC unit in no time.

Marion Minguillon - WA
5 stars rating

My AC was acting up, and I was worried about a hefty repair bill. However, the technicians quickly identified a minor issue, fixed it, and didn't overcharge me. I appreciate their honesty and expertise in troubleshooting the problem.

Sara Cribbs - VIC
5 stars rating

Thorough filter cleaning left no room for concerns, resulting in cleaner air and AC that requires less maintenance. Our home's air quality has improved dramatically, and we couldn't be happier with the outcome.

Lorenzo Rodriguez - SA
  • Mitsubishi Heavy Industries Air Conditioning Logo

    When looking for a leading supplier of wall mounted split systems, Mitsubishi Heavy Industries air conditioners offer reliable, high-quality heating and cooling perfect for Australian family homes.

  • Temperzone Air Conditioning Logo

    Temperzone is the award-winning global manufacturer of air conditioners and leaders in climate innovation with a wide range of systems suitable for Australian homes and commercial applications.

  • Bonaire Air Conditioning Logo

    Bonaire heating and cooling systems are economical, yet high performance. Their reliable air conditioners are manufactured in Adelaide and expertly designed to withstand year-round weather extremes.

  • ActronAir Air Conditioning Logo

    For incredible home comfort, you want ActronAir. Ducted systems or wall hung splits, ActronAir air conditioning has the best residential cooling solutions. You'll never complain about the heat again.

  • Fujitsu Air Conditioning Logo

    Stay comfortable all summer long thanks to Fujitsu air conditioning. Fujitsu ducted air conditioning units are perfect for Aussie homes so when you need repairs or servicing, call Metropolitan.

  • Sharp Air Air Conditioning Logo

    With over 100 years in the industry, Japan’s Sharp Air Conditioning is known for luxury products. Sharp air cons provide convenient and effective cooling performance, to deliver year round comfort.

  • Hitachi Air Conditioning Logo

    Are you ready to discover the incredible range of Hitachi air conditioners? We’re talking split systems, wall mounted, ducted heating and cooling and more. So plenty of options for achieving comfort.

  • Stadt Air Conditioning Logo

    STADT air conditioning is synonymous with high quality Australian owned ducted heating and cooling. For any STADT air conditioning service and repair, we are your Australian experts.

  • Haier Air Conditioning Logo

    With over 30 years in the industry, Haier is known internationally for its energy efficient and smart heating and cooling solutions. Haier heating and cooling is just a tap away.

  • Vulcan Air Conditioning Logo

    When you're after a Vulcan air conditioning service, you want Metropolitan. We're experts in Vulcan climate control, providing repairs and servicing for air conditioners.

  • Kelvinator Air Air Conditioning Logo

    Australians have enjoyed Kelvinator's cooling reliability for over 80 years. Whether you have a Kelvinator window air conditioner or Kelvinator split system, Metropolitan is here to help 24/7.

  • York Air Air Conditioning Logo

    For optimal year-round comfort from your AC unit, York is the name to know. Distributed by Bonaire, York air conditioners Australia offer superior AC solutions perfect for our Australian climate.

  • Lennox Air Conditioning Logo

    Lennox is a globally recognised brand with a great range of energy-efficient HVAC systems. Choose a Lennox air conditioner when craving that desirable climate control and year-round comfort.

  • LG Air Conditioning Logo

    LG is a world leader in consumer electronics, and its air conditioners are no different. From smart split systems to energy efficient ducted air conditioning, LG air conditioning does it all.

  • Midea Air Conditioning Logo

    Midea is an Australian giant with an international reputation for quality split system air conditioning. You can also find portable coolers and window boxes among the Midea air conditioner range.

  • Mitsubishi Electric Air Conditioning Logo

    Mitsubishi Electric supplies premium residential air conditioners in Australia. Their sophisticated designs, including their sleek wall split system models, are built to offer long-term comfort.

  • Panasonic Air Conditioning Logo

    The latest and greatest Panasonic air conditioners go beyond heating and cooling with air purifying features for healthier breathing. Sounds good, doesn’t it?

  • Rinnai Air Conditioning Logo

    Rinnai is a trusted household name in all things heating and cooling. From the Rinnai gas heater to inverter splits and reverse cycle ducted systems, there's a Rinnai solution for every Aussie house.

  • Samsung Air Conditioning Logo

    Samsung Air Conditioning is known for its reliability and performance. These efficient climate systems are as highly regarded as Samsung’s TVs, home appliances and popular Galaxy smartphones.

  • Brivis Air Conditioning Logo

    Brivis by Rinnai has been a titan in the air conditioning game for 50 years. With an impressive heating and cooling system range, the Brivis name goes hand in hand with quality and longevity.

  • Braemar Air Conditioning Logo

    Braemar has all your heating and cooling needs sorted. Evaporative cooling, ducted gas heating, space heaters, wall heaters, split systems and reverse cycle - Braemar has you covered year-round.

  • Carrier Air Conditioning Logo

    The Carrier air conditioning range is known for sustainability and affordable prices. As a leading Australian AC supplier, Carrier strives to improve the industry through innovative cooling solutions.

  • Breezair Air Conditioning Logo

    Are you after a market leader in evaporative cooling? You need Breezair. Breezair evaporative coolers are manufactured in Australia so you know you're getting cooling to stand the Aussie heat.

  • Kaden Air Conditioning Logo

    Simple solutions are the foundations of Kaden heating and cooling. Products like the Kaden split system are perfect for the ever changing Australian climate so you can always remain content at home.

  • Celair Air Conditioning Logo

    Celair is a leader in ducted evaporative air conditioning with over 40 years of experience behind them. Manufactured right here in Australia, Celair heating and cooling supports local Australians too.

  • NEC Air Air Conditioning Logo

    Beat the heat with a NEC split system. NEC has a heating and cooling solution that will keep you comfortable in all seasons. Experience superior energy efficient heating and cooling with NEC.

  • Coolair Air Conditioning Logo

    As an Australian owned and operated manufacturer, Coolair evaporative air conditioning makes a great high performance companion for anyone looking to escape the harsh heat of our great southern land.

  • Sanyo Air Conditioning Logo

    Sanyo air conditioning models were known for providing trusted AC performance. Although Sanyo no longer operates, Metropolitan can still offer expert 24/7 service to your existing Sanyo system.

  • Toshiba Air Conditioning Logo

    Toshiba air conditioning makes use of innovative DC Hybrid Inverter technology which automatically provides high capacity heating and cooling when necessary and minimises running costs when it’s not.

  • TECO Air Conditioning Logo

    TECO has been heating and cooling Australian homes for over 30 years. With split systems, multi splits, window/wall air conditioners and ducted air conditioning, TECO has the whole home covered.

Metropolitan Air Conditioning Service Reviews Metropolitan Air Conditioning Service Reviews