The Ultimate Guide to Buying Air Conditioning: Part 1

Types Of Air Conditioning

When you are faced with the plethora of air conditioning brands (let alone types), it can seem easier to just sweat it out through the summer rather than buying one. We don’t wish that upon anyone, especially in Australia, so we decided to put together The Ultimate Guide to Buying Air Conditioning.

This article is the first of a four part guide on everything you need to know to make an informed decision about your air conditioner. This first part outlines the types of air conditioner available for Australian homes. The second part addresses the key features of each air conditioner and how you can determine the best one to suit your home, budget and needs. The third instalment helps you compare brands of air conditioner, and the fourth how to choose the air conditioner retailer and installer to provide you with the perfect air conditioning system.

This guide is written for home owners looking to install air conditioning for the first time. To keep the guide short and easy to understand brief explanations are provided and not all angles are covered. An air conditioning specialist should be able to provide further detail.


Types of Air Conditioning

There are four types of residential air conditioner used in Australian homes:

How Air Conditioners Work

Air conditioners use refrigerant to add or remove heat from the air. When refrigerant changes state between being  a liquid or gas it causes a transfer of heat. On cooling mode the heat in the air is absorbed by the refrigerant and a fan distributes the now cooler air into the home. With a reverse cycle system, the flow of refrigerant can be reversed causing heat to be released from the refrigerant gas and the now warmer air to be blown into the home by the fan.  With a split system this process is split between two units: a noisier outdoor unit (containing a condenser and compressor) and a quiet indoor unit (containing a fan coil and a fan) which are linked by two pipes containing the refrigerant in a gas and liquid state.

Types of Split System

There are many types of split system. In general they are designed to heat or cool one room, while ducted reverse cycle systems are designed to heat or cool your whole home. For split systems to work most effectively, you should close the windows and doors of rooms that  require cooling (or heating).

Wall split systems are the most popular choice as they are the most affordable and easiest to install. This type of system is mounted high on the wall and is efficient at cooling because the cool air can sink through the room. Wall splits are designed to treat one room, with the indoor unit (fan coil) placed indoors on an exterior wall. The outdoor unit (condenser) is typically placed adjacent to the indoor unit but outside –  this is referred to as a back to back installation.

wall-split-system-installationFloor splits (also known as floor consoles) are like wall split systems but the indoor unit is installed at ground level rather than on the wall. Floor splits are more compact and are used where there is no space for a wall split. They can be semi-recessed into the wall, installed under or in front of a window or in an unused fireplace.

Cassette air conditioners are like wall splits but they are mounted centrally in the ceiling providing even air flow in four directions. They are fitted flush to the ceiling with the unit concealed in the roof space.

Bulkhead air conditioners are fitted in a bulkhead and are used where there is no wall space to fit a wall split and there is no ceiling space to install a cassette air conditioner.

Multi-head split systems are purpose built room split systems designed to be run by one outdoor unit. They are a better aesthetic choice than installing several wall split systems because you don’t have multiple outdoor units cluttering your outdoor area. Multi-head systems are very versatile as they can combine different types of indoor heads (wall, floor, cassettes, bulkhead or mini-ducted split systems). Each indoor unit has its own controller so the temperature in each room can be individually controlled. It’s not possible to join or convert standard split systems into a multi-head system.


Ducted reverse cycle air conditioners are the second most popular split system as they can cool or heat your whole home. The indoor unit is placed in the roof space and the cooled / heated  air is distributed to each room via ducting which releases the air into the rooms through ceiling outlets. The air is then recycled back to the indoor unit via the return air grille, which is located centrally in the home. They are a more attractive option than wall splits because they only require one outdoor unit and the ceiling outlets and return air grille sit close to the ceiling. Ducted reverse cycle air conditioning is operated by one controller so there is no need to turn controllers off in each room. (More controllers can be installed for convenience). Ducted reverse cycle systems are the most expensive to buy and run so they need designing correctly to suit your home and lifestyle. Zones are used to reduce running cost and system size.


Window Wall Units

Window wall units operate like split systems, using refrigerant to heat or cool the air. The air conditioner is a single unit which is installed in the wall making it cheaper to buy. These units are noisy because the compressor is installed in the wall. They are also inefficient and so nowadays are only used to replace existing systems where the occupant doesn’t want to brick up the hole left by the previous unit. However modern units are typically smaller than old units making the installation difficult. Falling popularity has meant limited brands are now available.


Portable air conditioners are cheap to buy and require no installation. However, when you look at the amount of cool and warm air generated compared to a wall split, they are relatively expensive to buy and run because they do not have the same efficiency, power or system life. Portable air conditioners suit people looking for a quick and temporary solution.

Evaporative Air Conditioners

Evaporative air conditioners are not “true” air conditioners because they do not use heat transfer to refrigerate the air. Their correct name is evaporative coolers. They work by drawing in large volumes of air through water soaked pads. When water evaporates it requires heat and that heat is drawn from the air going through the pads thereby making the air cooler. Air movement arises as some of the air evaporates. The combined effect is like being by the ocean in a pleasant breeze. Their performance drops in humid conditions because the air already has large amounts of water vapor and this reduces the amount of evaporation possible, hence cooling.

The evaporative unit is placed on the roof. A dropper box is attached to the underside of the evaporative air conditioner and from this ducting is attached. The air is drawn into the evaporative unit, travels through the ducting and vents into the rooms via ceiling outlets. Unlike split systems, the air is not recycled and instead it is expelled outside through open windows and doors.


 Read on for Part 2: Choosing the best Air Conditioner for You