Split System Air Conditioners: Everything You Need To Know

Fujitsu Air Conditioning Newcastle & Lake Macquarie

If you’re looking at buying a new split system air conditioner you may have noticed there are many different types of systems, designed to do pretty similar things. How do you know what air conditioning system is right for your home? 

In this post we cover everything you need to know about split system air conditioners including what is a split system air conditioner, pros and cons, how split systems work, what size unit you need, how much to install and how to clean your air conditioner. 

What is a split system air conditioner?

A split system air conditioner has two components, an indoor and outdoor unit. The indoor unit absorbs heat, while the outdoor unit cools and pumps cold air into the indoor unit. The two units are connected by insulated tubes which are piped through a small hole in the wall.

Pros and Cons of Split Systems

Split system air conditioners are the most popular air conditioning units in Australia. However, there are some disadvantages of split systems, especially for larger homes with open plan layouts. 


  • Can be installed in selected rooms in optimum positions
  • Additional units can be added at any time
  • Cheap to install
  • Cost-effective
  • Easy to maintain
  • Runs quietly and efficiently


  • The units can be unsightly
  • They can only push air so far, meaning that they struggle with larger rooms


How does a split system air conditioner work?

A split system air conditioner works by pumping refrigerant gas through the unit’s cooling circuit. As the gas pumps through the condenser, it cools down and vaporises into a liquid. The liquid refrigerant is then pushed into the evaporator, expanding and changing back into a gas. As the gas rapidly expands, the temperature drops dramatically. The gas then passes back to the condenser to repeat the process. 

Air from the room is drawn into the unit and passes over the evaporator coils, which cools the air. The cooled air is blown back into the room. The air continues to circulate until the desired temperature (set by the thermostat) is reached. When the desired temperature is reached, the unit shuts down automatically.


Do split systems heat and cool?

There are reverse cycle split system air conditioners, which provide heating and cooling from the same unit.

For cooling, the unit draws in the hot air and cools it, before pumping it back into the room. On the reverse cycle, the unit draws in ambient air and heats it before pumping it back into the room.  

The refrigerant travels through the system’s chambers before flowing to the condenser. Once the refrigerant is compressed, it begins to warm. Once heated to the desired temperature, it will flow through to warm the inside of your home. 

Read more about the heating benefits of reverse cycle air conditioning here.


What size split system do I need?

Choosing the right size air conditioner is extremely important to maximise performance and minimise running costs. Air conditioners that are too big will use more energy, while air conditioners that are too small will not cool the room sufficiently. 

The four biggest things that impact the size of the split system you need include:

  1. Room size
  2. Insulation
  3. Location 
  4. Orientation

Room size

Floor space and total volume of the room are one of the most important factors in determining the size of the air conditioner you will need. Rooms with higher ceilings will require more energy to cool.

Generally speaking, the following applies:

A 10m2 to 20m2 room will need a 2.6kW unit 

A 20m2 to 30m2 room will need a 3.5kW unit 

A 30m2 to 45m2 room will need a 5-6kW unit 

A 45m2 to 65m2 room will need a 7-8kW unit

However, it’s always a good idea to seek expert advice before making a decision. 


Ceiling insulation is one of the biggest factors in making your home thermally efficient. High quality insulation will help retain the cold air, helping your air conditioner run more efficiently and cost-effectively. 


Australia’s climate is so diverse. If you live in Darwin, you will need a much more powerful air conditioner compared to Hobart.

While we don’t get freezing cold or boiling hot temperatures here in Newcastle, we recommend reverse cycle split system air conditioners to provide you with ultimate comfort all year round. 


Which way does the room face? A large north or west-facing window can let in a lot of heat in summer, whereas a shaded, south-facing window will be a lot cooler. 


How much to install a split system air conditioner?

Split system air conditioners require installation by licensed professionals to safely handle gas refrigerant, conduct electrical wiring and plumbing into your home’s stormwater system. 

The outdoor unit is fitted on the exterior wall of the room that requires cooling. The indoor unit is then mounted on the wall in the room. Generally speaking, it’s better to install the air conditioner on a long wall of the room and not directly above a window.  

Installing a split system air conditioner usually takes about half a day. NewAge Air offers split system supply and installation from $1721. Read more in our post, Air Conditioner Installation Cost.


How to clean a split system air conditioner

You should clean your air conditioner twice a year. Regular cleaning and maintenance will help the unit run more efficiently and prevent costly repairs. 

Before you clean any part of your split system air conditioner, make sure it’s completely turned off.

The Indoor Unit

The indoor unit has dust filters that need regular cleaning. The more you use the air conditioner, the more often you will need to clean the filters. When the dust filters get clogged, the air conditioner has to work harder to push cool air through it, resulting in higher running costs.

To clean the dust filters, simply pop open the plastic cover and remove the filters. Take them outside and give them a good brush or shake, or vacuum with the dusting brush head. If the dust filters are really dirty, you can wash them in warm soapy water. Just make sure they are completely dry before putting them back in the air conditioning unit. 

You may also be able to remove the louvres (blades) inside the air conditioner. If so, clean them and the space behind them inside the unit thoroughly with a cloth or vacuum cleaner. 

The Outdoor Unit

Keep the outdoor unit clear of grass and plants and brush away dust, leaves and cobwebs regularly. 

You can run a vacuum cleaner over the air intake to help clear dust from the outside. But, leave cleaning the internal components to the professionals.

You find out more tips and tricks in our post, How To Clean Your Air Conditioner.


Split system air conditioners are the most cost-effective and versatile home air conditioning systems. No wonder they are the most popular air conditioning systems in Australia! If you’re looking to buy a new air conditioner, call our air conditioning specialists for expert advice and check out our range of split system air conditioners here.

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