Ducted vs. Multi-split System Air Conditioners: Which is Best?

Are you contemplating whether a ducted or multi-split system is better for your home? Both these systems have their pros and cons and are excellent choices for a central cooling system. There are things you need to keep in mind when deciding which system is best for you.

What to consider when deciding?

There are some limitations to each of these systems that we will discuss later but it is important to consider the following when deciding which system is best for you.

Does your home have a roof cavity? If so, how big is it?
Do you need to cool your entire home? Or only the living area?
How much external space do you have for outdoor compressors?
How much wall space do you have for wall-mounted evaporators?
Do you have any large open-plan areas (e.g. combined open-plan living, dining, and kitchen areas)
What passive cooling strategies can be integrated with an air conditioning system to optimize home cooling performance?

Now we are considering these factors, it's time to discuss what these systems are and the differences between them.

What is a Ducted and Multi-split System?

Ducted Air Conditioning Systems: Ducted systems use a series of pipes (ducts) to pump cool air into every room in your house. This allows for a discrete system as the evaporator (or inside unit) is positioned in the roof crawl space and is connected to a single external compressor.

Ducted Air Conditioner

Multi-split system Air Conditioner: Multi-split systems use a singular external compressor connected to a series of internal wall-mounted evaporators. This allows for select rooms to be cooled and does not require roof space.

Multi-split System Aircon

Pros and Cons of Each System

So what are the benefits and downfalls of each of these systems?

Running Cost: According to data from the Victorian government to cool a large house (220 m2) will cost $88 for a 4-star Multi Split System. They then determined the following (based on running cost estimates):

Ducted (refrigerative non-zoned) systems are 34% more expensive to run.
Ducted (standard evaporative cooling) systems are 267% cheaper to run.
Ducted (inverter evaporative cooling) systems are 440% cheaper to run.
And for a standard, a ceiling fan is 463% cheaper to run.

Cost of Purchase and Installation: Data presented by Canstar states that on average a ducted system will cost anywhere from $9,000 to $20,000 depending on house size. On the flip side, a multi-split system can set you back $3,900 to $4,900 making up for their higher running costs. On top of this, the cost of multi-split systems can be spread out over a longer period as the wall units can be installed as you need them (permitted that the compressor is large enough to support them). Ducted systems are required to be installed at once leading to higher upfront costs.
Zoning: A positive of both these systems is that they can be zoned. This allows for the system to only work in the rooms you need. The only difference between these systems is that multi-split system zoning will turn off the unit in the rooms where it isn’t needed, whereas a ducted system will just close off the ducts to those rooms.
Discreetness: Ducted systems are far more discrete when compared to a multi-split system. The only visible components of a ducted system are the vents that can be placed in walls or ceilings and the external compressor unit. Muli-split systems on the other hand have bulky wall-mounted evaporatetors that need to be in every room you want aircom on top of the external compressor.
Sound: Ducted air conditioning systems are far quieter than a split system.
Ease of Installation: Multi-split systems can pretty much be installed on all houses that have somewhere to store the compressor and walls that can support the evaporators. Ducted systems have a higher demand as they require roof space for the unit and ducts as well as a ceiling that is rated to support the weight of the system making it harder to retrofit into older homes.
Large Room Climate Control: Multi-split systems are not as efficient at cooling larger areas when compared to ducted systems and can be more costly to cool larger areas as you will need extra indoor evaporators which can prove to be more costly than extra ducts for a ducted system.

Both these systems are great options for home climate control systems if you need any more information about these here are some other articles we think you might find interesting:

References:

Ducted Air Conditioning vs Split System: Pros & Cons | Canstar

How much does ducted air conditioning cost? | Canstar

2023 What costs are involved in split system air conditioner installation? | Hipages

Compare Cooling Running Costs | Sustainability Victoria