Ducted air conditioning - your experiences

Hi CHOICE Community

I am currently looking into updating our ducted air conditioning buying guide at

We don’t test ducted air conditioning systems, as people’s experiences are all quite different. But what we can do is guide people on the journey. I thought including a few real-life scenarios would help bring the topic to life - along with some diagrams which could better explain the topic.

Has anyone here has an experience of installing a ducted air conditioning unit in their existing home? Can you elaborate on the experience, and perhaps explain the process – what went right? what would you do differently next time? did it cost more or less than anticipated? why did you choose a ducted solution over a split system and do you think it ended up being the best option for your home?

Any input would be greatly appreciated as the page does need a refresh. I am still only in the planning stages but would you also be willing to be a case study for the article?

Thanks in advance!

Kim Gilmour
team leader, household


Couldn’t afford the Roller when I retired so purchased a quick steer mower and a ducted air conditioning, Seasonal temperature since I have lived here (30 years) between - 6 to 40 + Air con is 6 years old and only gets used about 50 days a year., about 10 when it is cold 40 when it is hot. When its cold it is used mainly when our grandchildren sleep over but occasionally just because we can. The hot weather is getting harder for me to cope (69) as I get older so I really enjoy chilling out, the main benefit is the speed with which the system can make temperatures bearable. We have ceiling fans in four rooms which assist in running the system less. A very well shaded house on three sides and part of the day on the other.

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I had one installed around 2004 - there are a couple of things I remember well from the experience:

  • Got 3 quotes. They were all quite different. Two of the companies sent out what could be best described as ‘sales droids’. In the case of the third company, the owner came out - he also supervised and was involved (hands on) with the installs. Under detailed questioning, guess which one came through with the well thought out answers? You don’t have to know the business yourself, just ask lots of “why” questions about every detail and see how they answer. It becomes obvious fairly quickly who knows their stuff and who doesn’t.
  • A vendor can’t quote without a good look around your house, inside and out, every room, meter box and in the ceiling space unless they are either padding the price for a heap of what-if’s or they are making assumptions that could lead to corner cutting or a second grab at your wallet down the track.
  • Ask for a couple of references, one recent, one a couple of years old and one from a number of years ago.
  • Do your online research. Wasn’t as big a thing when I did it as it is now, but still useful.

Our job quotes were in the $15k range to put reverse cycle with multiple zones in a large 5br house with formal and informal living areas (casual dine, formal dine, casual lounge, formal lounge, family room and long hallways - we’d have needed at least 9 split systems to cover it - thankfully I live in a much smaller house now and only need a ducted swampy !).

The guy who got the job was the one I mentioned above who worked his own installs - amazing attention to detail and everything worked extremely well - Oasis in the Yarra Valley from memory and it was the middle price of the three. Would definitely do ducted again in this scenario and it as definitely worth being a bit particular in making the decision on who to go with. I reckon the only failure we had was a duct flap motor not long after install, which was quickly replaced.


This is very useful. Thanks @draughtrider - love the tips, especially ensuring that the vendor takes a proper look around.


I would like to hear more opinions. It seems my 11 year old ducted air con is nearing the end of its life. It was great for a long time and was used mainly in winter as we have reasonable passive cooling design. However, Brisbane summers are significantly worse than they used to be and winters milder so it has been a complete turnaround and the unit struggles I think, to keep us cool. I also have 5 bedrooms, an office and open plan living areas over 2 storeys. The unit is zoned and it manages better when we are able to switch off some of the house.
I don’t think the split system option would be good here. I would need quite a few and they are ugly in my opinion.
I have been told that newer air conditioners are more efficient. At the moment my electricity bills are high and I hope to be able to get solar. It seems that a new system would cost between $15 and $17k. A recent service guy told me that you have to replace the entire thing, ducts and all, due to mould. No one has looked to see if we have mould etc. Surely you can re use all the stuff in the roof?
The average life span of ducted air con is 10 and a quarter years.


Check the cassette split systems whereby you can have multiple cassettes with a single compressor. They have some cost but are relatively unobtrusive and lend to zoning. google ‘multizone cassette split system air conditioning’ An example casesette.


Ducted air conditioning was already in place when we bought our home 12 years ago. At that time the system was already about 6 years old. Three bedroom, double-brick home, configured as two zones.

We recently had a serviceman in to have a look at the general health of the system. He said we should expect it to last around 30 years altogether. So it should be good for about another 12 years.

We use it on perhaps a dozen days during summer, and almost every day in winter. Recently, I checked the specifications of the system and discovered that the outdoor unit was advertised as a system suitable for small business use, rather than domestic. I don’t know whether that would lead to it being longer-lasting…


Lived in Houston TX USA for many years. The climate is similar to Cairns some years and SE Qld others, and sometimes there can be a nasty cold winter in the single digits (F) for weeks. Life is running from an A/C house to an A/C car to an A/C job for most people. The point is the systems are run hard.

The typical life of the compressors there is 10~12 years. Sometimes a fan motor will wear out. Each is a discrete repair. The inside and outside coils usually last decades. Over my last 12 years there the A/C required nothing more than 1 fan motor replacement and service checks to make sure it remained gassed w/no leaks.

What is the basis for the ‘average life span is 10 years’?


Mostly for a good lifespan it is keeping the filters clean so the flow of air is at it’s best rate, & perhaps a yearly or two yearly maintenance check (depends on your usage). Ducting on it’s outside will get dusty but this is purely cosmetic, and if you keep your filters clean the inside will remain pretty pristine.

To make your usage as efficient as possible ensure your roof cavity is well insulated and if getting ducting installed go for the better insulated ones rather than the cheap. If you already have the not so well insulated ducting try getting as much as possible of it covered in batting to increase its insulation. I think what you are possibly noticing is that as the temps increase in summer your roof cavity is much hotter and you are losing efficiency due to you cooling the roof cavity so ensure you have good insulation in your roof and if needed around your ducting.

Ducted when it is used may keep your power bill higher even with zone control, partly due to where your temp sensor is located, and the much larger amount of power consumption when running for only a small number of areas eg 3 rooms at 12 Kw or using 3 splits at 3 Kw. With the splits each room has it’s own temp sensor and are thus running at their most efficient, cycling appropriately. With the ducted usually only having one sensor and it is perhaps quite distant from the rooms you are cooling the system probably will run closer to peak output all the time. If you don’t like the look of the outside units you can get or have built/made cosmetic coverings that “pretty” them up and don’t impede airflow.


Hi BBG, it’s just what the repairer told me, however just googling, there seems to be some basis to that claim. I think they start to break down and need expensive repairs at around that time at least.


Thanks, grahroll. I will have to look into the insulation in the roof. This is not something I had considered.


Fan motors and compressors are not cheap, though less than replacing a system every 10 years. But I understand where the advice comes from. Thanks,


I suspect you probably have the basic flexible ducting, it is a silvered polyester over a wire coil or similar product. It gets a rating of R 0.6, and since 2012 the BCA building code now requires a minimum R 1.0 for all duct work, and this R value increases based on your climate zone rating.

Max rating is R 2.4 for most spaces but is R 3.4 if ducting is exposed to direct sun. The R rating of the ducting can be reduced by 0.5 if used under a suspended floor with an enclosed perimeter or in a roof space that has insulation of not less than R 0.5 directly beneath the roofing.

Brisbane currently receives a Climate Zone rating of 2 (but I prefer to err on the side of caution and went with 3 on our house but it makes no difference to the duct R rating just the roof space R rating) so ductwork in an enclosed roof space must be at least a total R rating of R 2.0. If your current ducting is R 0.6 you should get a glasswool (or similar) product with a rating of at least R 1.5 to insulate it. You can go to a higher R rating if you like but a total rating of R 2.0 should make a decent difference to how much energy is lost from your ducting.

Just as a interesting note Toowoomba and related areas get a Climate Zone rating of 5 as they tend to have cool winters but Dalby and West of there get a rating of 3 as they tend to have warm winters.

For reference:

Zone 1  High humidity summer, warm winter
Zone 2  Warm humid summer, mild winter
Zone 3  Hot dry summer, warm winter
Zone 4  Hot dry summer, cool winter
Zone 5  Warm temperate
Zone 6  Mild temperate
Zone 7  Cool temperate
Zone 8  Alpine

What is the best all round ducted air conditioner for a 3 bedroom house?


Welcome to the community @Trelamina,

I moved your topic to this existing one. Full house ducted A/C seems a distant second to proponents for split systems (discussed in another topic) but you might find something here of interest, and forum indexing will bring this up to the top in ‘latest’.

Most related community discussions focus on efficiency, practicality, and costs, but many have other priorities, eg comfort, where central ducted wins hands down most of the time.

The Choice buying guide may also be useful.

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It’s worth considering installing a solar PV system at the same time if you do not have one. This will reduce the power costs and offset the total cost if you can export any surplus. It applies equally to homes with a split system option. This assumes you have the roof and sunlight for an effective PV install.


I’m trying to decide whether to spend a lot of money on airconditioning my home. I would like to know about other people’s experiences. also feedback on ducted vs split systems.

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Welcome to the Community @crusty,

I merged your topic into this existing one that while a bit old is germane.

For other replies to be a useful as possible, could you add your value system? Is it weighted toward operating costs? comfort? installation costs? Where are you located? Do you have a PV system?


It depends on so many things, here are some that come to mind straight away.

  • Do you need to heat/cool the whole home? Some find a smaller system in the bedroom is all they need, others not.
  • What is your climate? The more extreme the temperature range the more you need to control it. Is the problem more heat in summer, cold in winter or both? I once lived near the ocean and the winters were very mild and in summer the sea breeze came up nearly every day. Aircon would have been a luxury. We used a cheap fan heater a few nights in winter.
  • How well is the house insulated? Roof insulation and movable sunshades (or deciduous plants) on sun-facing windows may do much to manage your heat and there are no running costs. Even with aircon proper insulation will save a great deal of power. There is much good information here for free.
  • Do you have your own solar power? Where I live now the winter can get down to - 5C and summer up to 45C. The house is sun oriented and very well insulated and selectively shaded. I have solar panels and the aircon costs me little to run, mainly heating on cold winter nights. Mostly the aircon is on while the sun shines so I am using my own power which is the most economical use of the panels and the aircon.

Continuing the discussion from Ducted air conditioning - your experiences:

I live in Ipswich QLD. IThe most important thing to me is weighted towards comfort, now that I have decided to spend the money. Then it would be energy costs. I have a small solar array, around 5kw. It seems that the temperature in an individual zone, say bedroom, can’t be different to the “control room”, and the control room always has to be on, even if you only want to cool one bedroom?