Picking the right air conditioner isn’t complicated, but it’s one of those decisions where getting it wrong is expensive. An undersized system will struggle. An oversized one will short-cycle and waste energy. The wrong type for your home can leave you regretting the install for years.

The short version: split systems suit single rooms, small homes and apartments. Ducted suits whole-home cooling in larger family homes with the roof space to support it. The detail behind that decision, including what to look for in any system and why the install matters more than most people realise, is below.

Ducted air conditioning

Ducted systems cool or heat the entire home from one central unit, with conditioned air pushed through hidden ducts in the ceiling and out through vents in each room. They’re the go-to for larger homes or anyone who wants consistent comfort across the whole house.

A few things ducted systems do well. Zoning lets you run only the rooms you’re using, which keeps running costs reasonable even on a 38°C afternoon. The system is mostly hidden, so you see slim ceiling vents and a controller rather than a wall head in every room. And a single unit handles the whole property, which keeps maintenance simple, one service visit covers everything.

The trade-off is upfront cost (typically $9,000 to $14,000 for a competent install in a four-bedroom Sydney home) and the need for adequate roof space for ductwork. Federation homes and some inner-city terraces often can’t accommodate ducted at all.

Split systems

Split systems are the better fit for single rooms, smaller homes, or properties where running ducts isn’t practical. You get an indoor wall unit connected to an outdoor compressor, and each system runs independently.

They’re cheaper to install (typically $2,200 to $3,500 for a quality 7.1kW split, fitted), faster to fit (often a one-day job), and modern inverter splits are extremely efficient. The downside is that if you want to cool multiple rooms, you’re either installing several individual units or stepping up to a multi-split system that runs a few indoor units off one outdoor compressor.

Multi-split sits in an interesting middle ground. Less invasive than ducted, more capable than single splits, and often the right answer for renovated terraces or homes where ducted isn’t practical but you need cooling across several rooms.

Which one for your home?

It comes down to three things: how much of the house you want to cool, your budget, and whether you’ve got the roof space for ducting.

Single rooms or one open living area are split system territory. Three rooms or fewer with one main living area, splits still usually win on total cost. Once you’re past four rooms in regular use, especially in family homes where everyone’s home in the evenings, ducted starts earning its keep.

For larger Western Sydney homes (the four and five-bedroom builds across Oran Park, Leppington, Edmondson Park, Box Hill and similar growth-corridor estates), ducted is now the default for good reason. The temperature consistency across rooms is the thing most homeowners notice first, and it’s the thing splits can’t quite replicate.

What to look for in any system

Energy efficiency matters more in Sydney than most places, especially out west where summer days regularly push past 40°C. The energy rating label tells you how efficient a unit is at its rated capacity. The difference between a 3-star and a 5-star system on a typical Sydney home running aircon for half the year works out to a few hundred dollars a year on the power bill, which compounds to real money over the 15 to 20 year life of the system.

Look for inverter technology specifically. Older non-inverter systems run at one speed (full) and cycle on and off to maintain temperature, which is hard on the components and expensive to run. Inverter systems modulate continuously and use significantly less power across most operating conditions.

Smart controls and Wi-Fi connectivity are worth having if you want to run the system from your phone or set programmable schedules. Pre-cooling the house before you get home on a 38°C day is genuinely useful and a feature most modern systems support natively.

Brands matter too

We install ActronAir, Daikin, and Mitsubishi Electric most often because they hold up over the long term. The compressor warranties on these brands (5 to 7 years on quality models), the parts availability past the 10-year mark, and the day-to-day reliability are noticeably better than what we see on cheaper alternatives.

Cheap units can save you a few hundred dollars on the install and cost you thousands in early replacement. The premium for a quality brand on a typical residential install is usually 10 to 20% of the total job cost, and it’s the part of the spec that pays back most reliably over the life of the system.

The install is half the job

A great unit installed badly will underperform a mid-range unit installed well. Sizing, ductwork design, refrigerant pipe length, electrical work, and zoning setup all affect how the system runs for the next 15 to 20 years. This is the part where it pays to use a licensed installer with proper experience, not whoever quoted cheapest.

“We get called out to fix systems all the time that were installed badly two or three years ago. The unit’s fine, but the install was rushed. Wrong size for the home, ducts that leak into the roof space, refrigerant runs that are too long. The cheapest quote up front almost always costs more in the end.”

Helal, Crown Air

A competent install includes a proper sizing calculation against floor area, ceiling height, insulation and glazing (not a guess from the doorway), refrigerant pipe runs lagged properly and within manufacturer length specifications, electrical work compliant with AS/NZS 3000, and an ARC-licensed technician on the refrigerant work (federally required). The ARC licence number should be on the quote.

Ready for a quote?

If you want a system that’s properly sized, installed cleanly and built to last, the right next step is a site visit. We’ll walk through your home, your usage and your budget, and recommend something that actually fits, including being honest if a split makes more sense than ducted or vice versa.

Frequently asked questions

How long does an air conditioner last in Sydney conditions? With annual servicing, 15 to 20 years for both split and ducted systems. Coastal homes (within a kilometre of the surf) see faster outdoor unit corrosion and may need replacement closer to 12 to 15 years.

How long does installation take? A standard single split: half a day. Multi-split with three or four indoor heads: 1 to 2 days. Ducted in an existing home: 1 to 2 days, sometimes 3 for complex two-storey jobs. Ducted in a new build before plaster goes up is faster than retrofit.

Do I need approval to install ducted? Most freestanding homes don’t need approval. Apartments and townhouses usually require body corporate approval. Heritage-listed properties or properties in conservation areas may need additional consent for outdoor unit placement.

Can I add ducted to an older home? Usually yes, depending on roof space. A site visit is the only way to know for certain. Federation, Edwardian and some inter-war homes are the trickier cases where multi-split often ends up being the more practical answer.