Advice and News •
There’s a few types of air conditioner, and understanding the differences can be confusing. You can choose a split system, multi-split system, ducted system, a window unit, or a portable unit, each working differently, and with their own pros and cons.
In Australia, split systems are the most popular type of air conditioner, installed in millions of homes across the country. But what is a split system air conditioner, exactly? In this article, we’ll explain everything you need to know.
Table of contents
- What is a split system air conditioner?
- How does a split system air conditioner work?
- Where do the units of a split system air conditioner go?
- What is a multi-split air conditioner?
- What is an inverter split system?
- What are the best split system brands?
- What is reverse cycle air conditioning?
- What is the difference between split system air conditioning and ducted air conditioning?
- Is a split system easy to install?
- How much does a split system cost?
- How long do split systems last?
- What size split system air conditioner do I need?
What is a split system air conditioner?
A split system air conditioner is made up of two “split” units—a wall-mounted indoor unit that blows conditioned air into the home, and an outdoor unit that expels the heat gathered from the indoor system. Most people recognise split system air conditioners from the wall-mounted indoor units, which are usually white, between half a metre to a metre wide, and installed roughly two meters above the floor.
Daikin split system air conditioner (US7 model). Image from Daikin
Split systems are a good choice if you want to control the climate for a smaller space, for example a single bedroom, or a small one-bedroom apartment. They are suited to rooms up to 60m2.
How does a split system air conditioner work?
Refrigerant is the magical substance that makes air conditioning work. It can quickly change between gas and liquid, which also changes its temperature in the process. This change of temperature is used to heat or cool air pulled in by the air conditioning system.
In a split system air conditioner, the process starts with the refrigerant gas being fed into the outdoor unit’s compressor, where it becomes pressurised and heats up. The pressurised gas is fed through condenser tubes that turn it into a liquid, and then depressurised, which cools it and turns it back into gas.
As the refrigerant constantly cycles between cool gas and hot liquid, the air conditioner is able to use the changing temperature to cool the air it sucks from the room. As the indoor unit sucks air from the room, it passes it over an evaporator coil that has been cooled by the refrigerant gas, and becomes cold. The cold air is then sent back into the room.
The indoor and outdoor units are connected by electrical wires to provide power, and high pressure gas pipes to circulate the refrigerant through the system.
Where do the units of a split system air conditioner go?
The indoor unit is mounted to the wall, sitting roughly two meters high. It should be placed in a spot that allows balanced air flow throughout the room, as well as being easily accessible for cleaning and maintenance.
The outdoor unit is placed outside, usually next to the room with the indoor unit, to reduce the amount of piping and wiring needed to connect them. Because the outdoor unit expels warm air from the system using a fan, the area surrounding it can be a little noisy and warm. It’s best to place the unit in a corner, as far away as possible from any living space. It’s also important that the unit isn’t touching any walls, as the compressor and fan can cause it to shake, which may vibrate through the walls (or the walls of your neighbour).
What is a multi-split air conditioner?
A multi split-air conditioner is a split system with multiple indoor units. It works in exactly the same way as a standard split system, but can have up to five indoor units, all connected to a single outdoor compressor unit.
Multi-split systems are also suited to smaller properties with one or two indoor units. Anything larger, and a ducted system tends to be more energy efficient.
What is an inverter split system?
An air conditioner’s compressor is what pushes the refrigerant through the system, changing its temperature by pressurising and depressuring it. In a standard split system, the compressor has two modes—full speed, or off. When the compressor is going at full speed, and the desired temperature is reached, it switches itself off. In an inverter split system, rather than going full pelt until the set temperature is achieved, the compressor is able to change its speed, which allows it to pump just the right amount of refrigerant through the system. This makes an inverter split system around 30% more efficient than a standard split system. Most modern air conditioners use inverter technology.
With the inverter split system’s compressor able to cruise at the correct speed, it also tends to be quieter than a standard split system, which cycles between standstill and full speed. This extreme way of operating also wears down the compressor’s parts quicker, shortening its life and increasing servicing costs.
What are the best split system brands?
Mitsubishi Electric, Fujitsu, and Daikin offer some of the best split system air conditioners in Australia. A wide range of sizes are available from the three manufacturers, with various features, energy efficiency, and value for money.
What is reverse cycle air conditioning?
Reverse cycle air conditioners are able to produce both cool and warm air, and are a common feature for modern split systems. The system is able to produce warm air by reversing its refrigeration cycle, with the condenser becoming an evaporator, and the evaporator becoming a condenser.
What is the difference between split system air conditioning and ducted air conditioning?
A split system has two units—the wall-mounted indoor unit that blows conditioned air into a room, and the outdoor unit that compresses the refrigerant. These two units are connected by electrical wires and high pressure gas pipes.
Ducted air conditioning also has two units, but uses ducts to deliver conditioned air throughout a building. In a ducted system, the indoor unit is hidden in the ceiling cavity or underneath the floor, and rather than blowing conditioned air directly into the room, the air is circulated through ducts and released into the building from vents. Because airflow can be controlled from within the ducting, ducted air conditioning is able to designate zones throughout the system, which can be turned on and off individually. This allows you to turn air conditioning off for rooms/zones that aren’t being used, which saves electricity and reduces your power bill. Ducted air conditioning is better suited to homes that require a large amount of space to be cooled/heated, across multiple rooms.
Split systems are controlled with remotes, and ducted systems controlled with panels fitted to the wall. Both systems are able to have smart technology installed, allowing them to be controlled through phones, tablets, and computers.
Is a split system easy to install?
A split system air conditioner should take less than a day to install, and must be installed by a qualified professional. The air conditioning technician will need to create a small hole in the wall for the piping and electrical wiring, with no other changes needed for the building.
How much does a split system cost?
Air conditioning installers usually charge depending on the size of the unit and the electrical circuit required, with a cost between $650 -$850(+GST) for domestic installs.
You’ll need to add the cost of the indoor unit too, which starts at around $900.
How long do split systems last?
Split systems tend to last around ten plus years before needing serious repair, but this depends on the manufacturer. Professional annual servicing is recommended for all split systems, as well as cleaning air filters every couple of months.
What size split system air conditioner do I need?
In a split system, the size/capacity of the indoor unit is determined by several factors including cubic meterage of the room,Glazing, how much afternoon sun it gets, and whether the property has an insulated roof. Fujitsu have created a handy tool for calculating the required size for a split system.