Per room conditioned, the two are broadly comparable. Ducted air conditioning uses more energy than a split system because it cools the whole house, not just one room. A single split system running alone is always the cheaper option, but ducted becomes competitive once you’re cooling several rooms at the same time, and zoning determines the difference.
Split systems and ducted air conditioning are two of the most common setups in Adelaide homes, and running costs is part of the decision-making process. Below is what each actually consumes, what that costs per hour, and how to work out which is cheaper for the way you live.
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How Much Electricity Does a Split System Use?
A typical 2.5kW split system draws around 0.7kW of electricity, which works out to roughly 22 cents per hour at current South Australian electricity rates. Larger units scale up from there. Canstar figures put average Adelaide household consumption at about 180kWh per year per split system, or around $58 annually.
Split systems are a popular cooling choice across Adelaide for good reason: they’re compact, affordable and flexible enough to install in most rooms. For cooling a single room or a smaller space, they’re one of the cheapest options outside of evaporative cooling.
The catch is that the figure above covers one small unit. Cooling three rooms means three units and roughly three times the cost, and cooling a whole house this way gets expensive quickly.
How much yours uses depends on its age, its efficiency rating, the size of the space it’s working on, and how well insulated that space is.
How Much Electricity Does a Ducted System Use?
A ducted system with 7kW of cooling capacity draws roughly 2kW of electricity, or about 65 cents per hour to run. Larger whole-home systems of 14kW to 20kW draw around 4kW to 6kW, putting them in the range of $1.30 to $1.90 per hour at full output.
Run a 7kW ducted system two hours a day across summer, and you’re looking at somewhere near $115 for the season. That figure climbs with system size and with how much of the house you’re conditioning.
Zoning is what keeps that number down. Modern ducted systems let you section off parts of the house and send cool air only to the rooms in use, so you’re not paying to condition empty bedrooms during the day. A ducted system running two zones out of six costs a fraction of the same system running wide open.
Ducted vs Split System
| Feature | Split system | Ducted system |
|---|---|---|
| Typical cooling capacity | 2.5kW – 8kW | 7kW – 24kW |
| Typical power draw | 0.7kW – 2.3kW | 2kW – 7kW |
| Approximate cost per hour | 22c – 75c | 65c – $2.20 |
| What it cools | One room or open space | Whole home, zone by zone |
| Cheapest when | You’re cooling one or two rooms | You’re cooling most of the house at once |
| Main cost | How many units you run | How many zones you open |
Is Ducted or Split System Air Conditioning Cheaper to Run?
A single split system is cheaper to run than a ducted system, but ducted becomes the cheaper option once you’d otherwise be running three or more splits simultaneously, because one larger compressor operating efficiently beats several small ones all working at once.
The deciding question is how much of your home you actually use at once. A couple who spend their evenings in one living area will spend less with a split system. A family of five with people in different rooms will usually spend less with a zoned ducted system than with four or five splits running in parallel.
Other factors worth weighing:
- How many hours a day the house is occupied
- Whether the home is insulated, and how well
- Whether you need heating as well as cooling
- The size and layout of the home
- Upfront installation cost
How Can You Reduce Your Air Conditioning Running Costs?
Keep the system serviced, clean the filters regularly, use zoning or close doors to limit the space you’re conditioning, and set the thermostat to a moderate temperature rather than the lowest one available. Heating and cooling accounts for around 40% of household energy use in Australia, so small improvements here make a big difference to your bill.
Air conditioners contain plenty of parts that all need to stay clean to run efficiently. A yearly service should cover:
- Cleaning or replacing filters
- Cleaning the condenser
- Cleaning and clearing drains
- Checking the refrigerant system, which must be done by an ARC-licensed technician
- Inspecting and testing motors and components
A clogged filter or a dirty condenser forces the system to work harder for the same result, which shows up directly on your power bill.
Need to Service Your Air Conditioning? Contact Air Conditioning Doctor Today!
Whichever system you have, how well it’s maintained affects what it costs to run. Dirty filters, blocked condensers and low refrigerant all make a system work harder for the same output.
Air Conditioning Doctor services air conditioning systems across Adelaide, and we can tell you whether your system is running the way it should be. If you’re weighing up a new installation, we’re happy to talk through what suits your home and how the running costs compare.
Get in touch with us today to book a service or arrange a quote.
Frequently Asked Questions
Is ducted air conditioning cheaper than running multiple split systems?
It can be, once you’re running three or more splits at the same time. Below that, split systems are cheaper because you’re only powering the rooms you’re in.
Does zoning actually save money?
Yes. Zoning reduces the volume of air being conditioned, and the system draws less power as a result. It’s the single biggest lever on a ducted system’s running costs.
What temperature should I set my air conditioner to?
24 to 25 degrees in summer. Every degree lower increases the work the system has to do, so a moderate setting costs noticeably less than the lowest one available.
Does a bigger air conditioner always cost more to run?
Not necessarily. An undersized unit running flat out can use more power than a correctly sized one cycling comfortably. Sizing the system to the space matters more than choosing the smallest option.
Stephen Maitland is the Director of Air Conditioning Doctor and has over 20 years of experience in the refrigeration and air conditioning industry. He founded the company in 2007 to be Adelaide’s leading air conditioning repair, replacement and installation specialist.
As a certified Refrigeration Mechanic with a full unrestricted ARC license, his technical knowledge and years of experience allow him to diagnose problems quickly and offer practical and efficient solutions for his customers.
