Ducted vs Split System Air Conditioning: Which Suits Your Adelaide Home?

The ducted vs split system question comes up in almost every Adelaide home that wants reliable cooling for summer and heating for winter. Both are usually reverse cycle air conditioners, and both use an outdoor unit connected to an indoor unit by refrigerant pipes. The difference is how the cool or warm air reaches you: one wall unit per room, or one hidden unit pushing air through ducts to ceiling vents.

This guide compares the two on comfort, running costs, installation and ducted air conditioning cost drivers, then covers evaporative vs reverse cycle for homes that already have an evaporative cooler. For the services, see ducted air conditioning and split system installation.

What is the difference between ducted and split system air conditioning?

energy.gov.au describes a split system as two units, an exterior compressor and an interior unit, connected by pipes that carry refrigerant. The interior unit can be non-ducted, such as a wall-mounted unit, or ducted in the roof cavity and connected to various points of the home through ductwork.

• Split system (wall-mounted). One indoor unit on the wall of a room, one outdoor unit. Each unit has its own remote.
• Multi-split. Two or more indoor units connected to one outdoor unit.
• Ducted. A larger indoor unit in the roof space, with ducts to vents in each room and a central controller. Zoning lets you choose which areas get air.

Ducted vs split system: side-by-side

Factor	Split system	Ducted system
Coverage	One room or open area per indoor unit	Most or all of the home
Upfront cost	Lower per room	Higher overall, a larger project
Running efficiency	energy.gov.au says wall units are more efficient	Larger fan and duct losses make it more expensive to run
Look	Visible wall unit in each room	Discreet ceiling vents and a wall controller
Control	Each room controlled separately	Central controller, zoning by area
Roof space needed	No	Yes, enough height and access for the unit and ducts
Install time	Often within a day per unit	Several days for a full home
Noise in rooms	Unit fan in the room	Air noise at vents; main unit in the roof
Breakdown impact	One room affected	Whole system affected

energy.gov.au also notes ducted systems are more cost-efficient than gas heating, which is worth knowing if you’re replacing ducted gas heating.

When does a split system make more sense?

Split systems tend to suit:

• Homes where you mainly cool or heat the living area and main bedroom.
• Smaller homes, units and townhouses.
• Older homes with low-pitched roofs, little roof space, or solid brick construction that makes duct work hard.
• Extensions, home offices and granny flats.
• Households that want to add rooms over time rather than all at once.

A few well-placed split systems can cover a typical home, and each room runs only when you need it. Our guide to split system installation cost explains what drives the price of each unit, and what size air conditioner helps with sizing.

When does ducted make more sense?

Ducted tends to suit:

• Larger homes with several bedrooms and living areas used at once.
• New builds and major renovations, where ducts can be planned before ceilings are finished.
• Homes with enough roof space for the unit and ducts.
• People who want one controller and no wall units in each room.
• Households that want even temperatures through the house during long heatwaves.

Zoning is important. Being able to switch off bedrooms during the day and living areas at night stops you conditioning empty rooms, which helps with running costs.

What affects ducted air conditioning cost?

Ducted air conditioning cost is driven by the size of the job and the house. A technician needs to inspect the roof space and plan the layout before quoting.

Cost driver	Why it matters
System capacity	Larger homes need larger units.
Number of outlets	More rooms means more ducts, vents and labour.
Zoning	Each zone needs motorised dampers and control.
Roof space	Low or cramped roof spaces slow the installation.
Two storeys	Getting ducts to the ground floor can need bulkheads or ducts through cupboards.
Controller	Basic wall controllers versus app-controlled or room sensor systems.
Electrical work	Ducted units need a dedicated circuit, which may mean switchboard work.
Removing old systems	Taking out old ducted gas heating or an evaporative cooler adds time.
Return air	The return air grille needs a suitable central location.

What to ask the installer:

• How many zones, and which rooms are in each?
• Where will the return air grille and the controller go?
• What size and type of duct will be used, and how is it insulated?
• Does my switchboard need work for the new circuit?
• Where will the outdoor unit go, and how loud will it be?
• What does the manufacturer’s warranty cover, and what servicing does it require?

Evaporative vs reverse cycle: which suits Adelaide?

Many Adelaide homes already have an evaporative cooler on the roof. energy.gov.au says evaporative coolers work well in low-humidity inland regions. They cool by blowing air over water-soaked pads, need windows or doors open to work, and don’t heat.

Factor	Evaporative	Reverse cycle
How it cools	Evaporating water	Moving heat with refrigerant
Heating	No	Yes
Humid days	Less effective	Works regardless of humidity
Windows	Need to be open	Kept closed
Water use	Uses water to run	No water used for cooling
Efficiency	Low electricity use	energy.gov.au says reverse cycle units range from 300% to 600% efficient

Adelaide’s dry heat suits evaporative cooling on many days, but humid summer spells and the need for winter heating lead many households to switch to reverse cycle ducted or split systems. If you are replacing an evaporative cooler, the existing ducts may or may not be reusable, so ask the technician to inspect them.

What about running costs over time?

Running costs depend on how you use the system as much as which type you choose. A few things make a real difference in either case:

• Only condition the rooms you’re in. With splits, that means switching off units in empty rooms. With ducted, it means using zones.
• Set sensible temperatures. Every extra degree of cooling on a hot day makes the system work harder.
• Keep heat out. energy.gov.au suggests gap sealing, thick curtains, external shading and insulation to reduce heating and cooling loads. In Adelaide, shading west-facing windows helps a lot on summer afternoons.
• Service the system. Clean filters and a checked outdoor unit help either type run as designed. See air conditioning servicing.
• Use solar if you have it. Running cooling during the day while panels are producing can offset part of the cost.

A ducted system that is zoned and used carefully can be reasonable to run, while split systems left on in empty rooms can cost more than expected.

Who can install ducted or split systems?

Both types need licensed trades. The Australian Refrigeration Council says handling fluorocarbon refrigerant without a Refrigerant Handling Licence is an offence, and this includes installing and servicing air conditioning equipment. The electrical connection must be done by a licensed electrician, who should issue a certificate of compliance. Don’t attempt either installation yourself.

When should you call a licensed tradie?

Call an air conditioning technician when:

• You are deciding between ducted and split systems and want a site inspection.
• Your evaporative cooler or ducted gas heater is near the end of its life.
• You’re building or renovating and want ducts planned early.
• Existing units are struggling on 40-degree days.
• A unit is leaking water or not cooling. See aircon leaking or not cooling.

For more help, see our Adelaide air conditioning page.

Getting it sorted

Send one enquiry through our contact page or call 08 6800 6079. We pass it to one local air conditioning technician, who calls you back within 24–48 hours to inspect your home, discuss ducted vs split options and quote before any work starts.