Consumer Guide: Essential Advice for Split System Air Conditioners

Essential Advice for Split System Air Conditioners

What is a split system air conditioner?

Split system air conditioners have two parts:

  • An indoor unit that blows the conditioned air into the room, and contains the system’s air filters, return air, and evaporator coil (among other things)
  • An outdoor unit typically called the condenser or compressor. This contains the compressor, condenser, and cooling fan for the system.


The two units are connected together by copper piping, which moves the refrigerant around the system. Refrigerant is the “lifeblood” of every AC system and allows it to turn hot air into cool, and vice versa. The units are also connected with electrical cables.

Split systems are suited for cooling smaller spaces, or properties where there are just one or two rooms to be cooled. They’re popular in apartments and small homes for this reason, or homes where you only want a single space to have air conditioning (typically the living area, but also commonly the master bedroom).

The beauty of split systems is that you can add extra indoor units to other rooms, and connect them to the same outdoor unit. This is called a multi-head split system, and makes expansion much easier.

Typically, the indoor unit of a split system is mounted on the wall, called a “wall-mounted split system.” But there are many other types, including:

  • Floor-standing split systems—these are located on the floor, and are better suited for heating because heat naturally rises, and cool air naturally sinks.
  • Under-ceiling split systems—these systems sit just under the ceiling itself, with the fan blowing directly into the room below. They are suitable for areas that have limited wall space.
  • In-ceiling split systems—these provide a similar solution to under-ceiling splits, and tend to be used when there is limited wall space for a wall-mounted system. They are also called “cassette systems.

What type of air conditioner do I need?

Different spaces have different air conditioning needs, and being informed about these requirements is important when considering a new split system air conditioning system. Things like location (one or two bedrooms, a living room, etc.), size of the area to be cooled or heated, how often it will be used, and electrical ability can affect which system will work best for you.

Split system air conditioning units are becoming increasingly popular in the Brisbane area, and there are many advantages to these units. In Brisbane, we know the weather can go from one extreme to another – freezing cold or uncomfortably hot. Split systems can cater to all temperatures in this range, and are available in single split, multi split and wall-mounted options. These systems are quick to install, easy to maintain and the different styles can fit seamlessly into any home, office, or commercial space. Advances in technology mean these systems have a variety of installation options, simple, user-friendly operation, and unrivalled energy efficiency.

As the most versatile air conditioning option, split air conditioners can also fit in with your working-from-home budget. All home office systems are tax deductible. The electricity used to run these systems can also be claimed on tax, as can the services and any maintenance needs. As working-from-home situations are increasing, this is a great investment if you have a spare room to work from or a home office.

What size split system do I need?

Usually, the bigger your room, the bigger-sized split system you’ll need. But for an accurate measurement, you’ll need to know a couple of things:

  • The square meterage of the space
  • The ceiling height
    • 2.4 metre = 150 watts
    • 2.7 metre = 160 watts
    • 3 metre = 175 watts

To calculate your split system size, you’ll need to multiply the square meterage by the number of watts based on your ceiling height, as shown above. So if your room is 25m2 with a ceiling height of 2.4 metres, the calculation would be 25 x 150, which comes to 3,750 watts. That means you’ll need a split system that is roughly 3.75kW in size.

However, a reputable air conditioning company will be able to recommend the exact split system size you need for your property so that you have a system that functions optimally.

Do I need to replace my split system?

Split system air conditioners, like many appliances, need maintenance to extend their life. This includes regular servicing by an air conditioning expert and cleaning of the filters in between services, especially if you use your split system a lot.

If your unit has stopped working, you can try the following:

  • Check that the isolation switch adjacent to the outdoor unit is turned on—this is more common than you think!
  • Make sure the outdoor unit is clear of debris.
  • Check the circuit breaker for the air conditioner

If these quick solutions don’t work, there may be other issues, particularly if the systems are older. While repairs can be done, it can be more cost-efficient to replace these systems altogether, particularly if the units are more than 10 years old. The team at Mercury are happy to offer advice on whether maintenance, repair or replacement is the best option. For those wanting to install a completely new system, proper installation and electrical work can save you money in the long run—at Mercury, our team of specialists are fully qualified and licensed in electrical work, which takes the hassle out of the process.

We have installed thousands of split systems, and can tailor the system and process to suit your personal needs. The availability and range of split systems can be overwhelming, and it is hard to know which brands to trust, and which is best for your needs—we’re here to take that stress away. Customer satisfaction is our priority, and we can recommend the best system for your space and needs. We use leading brands that are efficient, safe and trustworthy.

What is reverse cycle air conditioning?

Reverse cycle air conditioning allows you to both cool and heat your home. Reverse cycle air conditioning is a great alternative to a heater, even for Brisbane’s milder winters.

What is inverter technology?

Modern air conditioners use inverter technology, which allows the system to control the speed of the compressor. For older systems, the compressor only has two modes: on and off. This means that it has to run at full speed until the set temperature is achieved, before turning off again—an inefficient way of doing things. Inverters allow the compressor to run at the exact speed needed to regulate the temperature, without having to exert itself.

Inverters have allowed air conditioning systems to become around 30% more efficient.

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