Ducted vs Split System: What Actually Decides It When You're Cooling a New Melbourne Home
In short
Choose ducted when you want most of the home cooled from one hidden system and the build has the ceiling space to run ducts. Choose split or multi-split systems when you mainly cool a few rooms at a time, want the most efficient option room by room, or the design leaves little room for ducts.
In a new build, make the call before the frame and ceilings are locked in, and make it together with your heating plan.
Key takeaways
• Ducted reverse cycle air conditioning cools the whole home from one indoor unit hidden in the ceiling, through a vent in each room.
• A split system cools one room or open-plan area; a multi-split runs several indoor units from one outdoor unit.
• The Australian Government's YourHome guide says ducted systems are less energy efficient because fans have to push the air through the ducts.
• Zoning lets you switch off the rooms you are not using, which is the main way to keep a ducted system efficient day to day.
• From January 2027, all new homes in Victoria must be built all-electric, so your cooling choice and your heating plan now belong in the same conversation.
Most people building a new home in Melbourne ask us the same question once the floor plan is settled: ducted or split? The honest answer is that neither is better in general. One of them is better for your home, the way you live in it and the way you plan to heat it. Here is what actually decides it.
What is the difference between ducted and split system air conditioning?
A ducted system has one indoor unit hidden in the ceiling space (or under a suspended floor), with insulated ducts carrying air to a flush vent in each room and one outdoor unit outside. A split system has a wall-mounted indoor unit in the room it serves, connected to its own outdoor unit by refrigerant pipes. A multi-split sits in between: one outdoor unit running several indoor units, each with its own temperature control. Energy Victoria's buying guide describes a single split as suited to one room or open-plan area, and ducted as suited to the whole home.
All three are refrigerated systems, and reverse cycle models heat as well as cool. Every split system we install is reverse cycle. You can see how each format looks and fits on our ducted system and split system pages.
What actually decides it?
Five things settle it in almost every new build we see.
1. How many rooms you cool at the same time
If the whole household is home on a 38 degree afternoon and you want every main room comfortable at once, ducted does that from a single system. If cooling mostly means the living area during the day and bedrooms at night, two or three splits, or one multi-split, will usually do the job with less equipment running.
2. Ceiling space and the design of the house
Ducted needs room above the ceiling for the indoor unit and the duct runs. A single-storey home with a generous roof space is straightforward. Cathedral ceilings, a concrete slab above, or an upper floor sitting directly on the lower ceiling make ducting much harder. The advantage of building new is that ducts are far easier to plan in at frame stage than to retrofit later, so this is the moment to check it. If ceiling space is tight but you still want clean walls, a bulkhead systemhides the indoor unit in a plasterboard soffit.
3. Whether you will zone it
A standard ducted system treats the house as one zone: turn it on and every vent opens. Zoning changes that. With a system like MyAir zoning, you can switch rooms on and off and set temperatures from your phone, so you are not cooling empty bedrooms in the middle of the day. Energy Victoria recommends zones for ducted systems and describes them as the more efficient option for ducted heating and cooling. If you are leaning ducted, plan the zones with the floor plan, not after.
4. How it looks
Ducted is the least visible option: only flush vents show. A split leaves a white indoor unit on the wall of each room it serves. For some homes that is fine; in a feature living room with a lot of glass it can be the deciding factor.
5. How it fits your heating plan
This is the factor most people miss. From January 2027, all new homes in Victoria must be built all-electric, which rules out gas heating in a new build. If your heating will be reverse cycle, your cooling system is also your heating system, so it needs to be sized and zoned for July as well as January. If you are heating with hydronic radiators or underfloor heating running from a heat pump, you may only need cooling in the living areas and bedrooms, and well-placed splits or a multi-split often make more sense than a full ducted system.
Which costs less to run, ducted or split?
Room for room, a split system is generally the more efficient choice. YourHome, the Australian Government's guide to sustainable homes, notes that ducted systems are less energy efficient because they need fans to push air through the ducts, and that ducts lose energy if they are not well insulated and sealed. Zoning narrows the gap by only cooling the rooms you are using.
Beyond the format, two things drive running costs: efficiency and sizing. Reverse cycle air conditioners carry a zoned energy rating label, and the more stars a product has, the less energy it uses. YourHome's advice is simple: choose a high efficiency model of the correct size. We do not quote a running cost figure until we have seen your plans, because the size of the rooms, insulation and glazing change the answer.
Why does sizing matter so much?
A system that is too small cannot keep up on a 38 degree day, and one that is too large costs more than it needs to. Energy Victoria says the best way to size a reverse cycle air conditioner correctly is for the installer to do an onsite load assessment and calculation. That is why we work out capacity room by room from your plans, not from a rule of thumb.
When should you decide in a new build?
Before the frame goes up, or at the latest before the ceilings are lined. By then your builder needs to know where ducts run, where the indoor unit sits, where outdoor units go and where power and drainage are needed. Changing your mind after plasterboard is possible, but it costs more and limits your options. If you are a builder specifying for a client, see how we work with architects and builders.
A quick way to decide
• Lean ducted if you want most of the house cooled at once, you have good ceiling space, clean walls matter, and you will use zoning.
• Lean split or multi-split if you mostly cool two or three rooms, your heating is hydronic, ceiling space is limited, or you want the most efficient option room by room.
• Talk it through if your home is two storey, has raked ceilings, or you are still deciding how to heat it. That is where a site-specific design earns its keep.
Cooling also books out early in Melbourne. Our crew explains why in book your cooling now, not in December, and if you are weighing up incentives, read the Victorian air-con rebate landscape after the July 2026 changes.
Frequently asked questions
Is ducted or split system better for a new Melbourne home?
Neither is better in general. Ducted suits homes where most rooms are cooled at once and there is ceiling space for ducts. Split or multi-split systems suit homes that mainly cool a few rooms, have limited ceiling space, or heat with hydronic.
Are split systems more energy efficient than ducted?
Room for room, generally yes. The Australian Government's YourHome guide says ducted systems are less energy efficient because fans have to push air through the ducts. Zoning a ducted system reduces the gap by only cooling the rooms in use.
Can a ducted system cool only some rooms?
Yes, if it is zoned. A zoning system such as MyAir lets you switch rooms on and off and set temperatures from your phone, so you are not cooling empty rooms.
Do ducted and split systems also heat?
Reverse cycle air conditioners, whether ducted or split, heat and cool with the same equipment. In an all-electric new build, that means your cooling system may also be your main heating system, so it should be sized for winter too.
When should I choose my cooling system for a new build?
Before the frame goes up, or at the latest before the ceilings are lined. Your builder needs to know where ducts, indoor units, outdoor units, power and drainage go.
Your next step
Building new and not sure which way to go? Send us your plans and book a free assessment. We will check the ceiling space, calculate the right capacity room by room, and tell you straight whether ducted, split or multi-split is the right call. Not ready to talk yet? Take the 2-minute system finder first, or call 1300 139 177.
