Buying a split-system air conditioner: buy in store, or via an installer?

I used a calculator when we installed Fujitsu 7.4kw splits in the kitchen and dining room and a Fujitsu 3.7kw split in the master bedroom at our previous residence which seemed to fit the bill despite the “installer” saying he did not believe they would be adequate.

They were expensive to run, but the open plan kitchen, dining room and lounge room were all large and the internal staircase allowed air to spill downstairs and/or hot air to rise.

The house was on the North side of the hill and missed the prevailing breezes from the SE.

It had insulation under the colorbond but no rotary ventilators.

The house was a hot box.

When we bought our current home some 5 years ago, it already had the same aircons in the kitchen and master bedroom and a non-inverter Fujitsu split in the lounge room which promptly failed the first time we turned it on, and was replaced with the same Fujitsu split as the kitchen has.

The rooms are smaller than our previous residence, the house is single storey, there is insulation under the colorbond and Rudd’s batts above the ceiling, with 2 rotary ventilators on the roof.

The house faces South and the prevailing SE breezes come straight up the hill.

When we inspected the house before buying it, it was around 5:00 PM in mid January, and it had been locked up all day as the owner had moved out.

We could not believe how cool it was.

Even during the high heat and humidity during the past few weeks, all 3 aircons do not use more than 2kw of power in total in the middle of the day, and will be only be drawing around 1kw at cooler times.

When we get up in the morning, the bedroom aircon is usually only drawing around 200 watts or less.

So 2 different residences with exactly the same aircons but with very different efficiencies and power usuage.

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This version worked well in a comparison I ran against our recent new aircons. That it considers climatic regions as well as wall and floor configurations plus windows and shading makes for a more detailed assessment. There was one exception.

The one minor weakness is it has no provision to account for rooms such as kitchens which have additional heat loads from appliances. It suggested 5.5kW cooling for our kitchen sized room. But with no allowance for intermittent heat loads from the fridge and dishwasher, leaky old fashioned joinery, gas cooking and an exhaust fan for the stove top. Our installed inverter split system is sized for 7.0kW. It is more than adequate for SE Qld rural heat and humidity.

In addition to @Fred123 prior comment that slightly oversize may have some other benefits of not working as hard, inverters are very efficient. They adjust how hard they work and therefore the power consumed to match the actual cooling or heat load. Hence for our kitchen with a quality inverter split system, having extra installed capacity does not result in a similar increase to power consumption. It will only consume as much power as is necessary to do the job.

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The purpose of installing a split is relevant. If it is to be the primary heating and cooling unit it should be sized accordingly. If it is to ‘backfill’ on a few hot days it just needs to be able to do the job. 10-20 days operation over a year is going to be a different ‘problem’ than if it is going to be used 180 days+.

In my case I have an evap system that is adequate most of the summer, and a hydronic heating system that is very nice, and added the split for the increasing number of hot and humid days where the evap could not cope. Running the split ‘hard’ for a few days? Additional capacity would have required another unit, essentially doubling the installed price, since the 9.4 KW was the largest on the market and it has shown it can cope at ‘much less than flat out’. Heating? Not so important and seldom used.


That’s referred to as a ‘back to back installation’, and when you see a supply and install price quoted in advertising, that’s what it will be for. Nothing wrong with that at all, but if you need a more complex installation the price will be higher.


Quite understandable as there is more copper tubing, more cable, more ducting, more conduit and more labour including creating 90 degree bends on the copper tubing.

Also worth noting that often, suppliers and installers will be very closely linked. Installer’s vehicle (and/or advertising materials) covered in branding from one manufacturer? the manufacturer likely paid for it for the installer. Also, manufacturers often offer spivs and other incentives for installers to encourage them to buy their product (free family holidays, sorry, international study tours for example, rebates, or even subsidised business services). As such installers are more likely to a) recommend the brand that’s going to offer them the best holiday at the end of the year, and b) not be keen to take on installations for systems you’ve purchased themselves - the amount of work’s about the same, but it won’t count towards their targets from the manufacturer. Does this mean that going with an installer supplied unit means you’re stuck with a brand that the installer likes? absolutely not - there’s plenty of installers out there, aligned with all sorts of brands - choose the air conditioner you like, then find an installer that supplies that particular brand - then take advantage of their experience and expertise in choosing the size of air conditioner you need and to plan the installation and locations.
Finally, and I can’t stress this enough, regardless of whether you source your own unit or go with one supplied by the installer, check they have the necessary qualifications to do the work - ALL the qualifications. Fridgies should all have an Arc Tick qualification, but that only covers working with refrigerants - they should also have an electrical certification in order to wire the air conditioner in legally and correctly - many don’t, and while wiring an air conditioner is ‘relatively’ simple, an unlicensed installer means you won’t have warranty support on the electricals, just the compressor and refrigerant. And if the drain pipe needs to be plumbed into the stormwater then the person doing the work needs to be a licensed plumber too.
All these qualifications take time and money to get, and there are various other costs of running a business too - insurance for example, and paying employees and the tax man correctly. While you should always shop around for the best price, if a price seems too low then ask yourself what the installer is doing without…


That’s what you pay the expert for - not to bend the pipe to 90 degrees, but to bend the pipe to 90 degrees in such a manner that it doesn’t kink and block the flow of refrigerant, and to bend it in a way that’s safe, secure and unobtrusive on the side of your home. ie, any fool can bend a pipe, but not everyone can bend it well…


As someone who is a supplier to the refrigeration industry I would always say to purchase the unit yourself and engage a installer. The problem with the buying a unit with installing is the price quoted will only cover basic install. So you will pay extra for a bracket, extra if the unit is not back to back, extra if the distance from the meter box exceeds 3-5 metres and this where charges become excessive. My industry tells me the installers make very little money and do cut costs in order to be profitable. This does not apply to ducted units only wall hung split systems.

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Industry tells me that the professional air conditioning suppliers have two options when quoting and installing.

One is to quote the job profitably using their own employees. Trade on a positive reputation over lower cost.

The alternative is to offer the job to their pool of sub contractors seeking the lowest cost. This is a risk as the “subie” did not quote the job, and there is a second profit grab in the process. Can we assume this is the focus of your advice?

Some businesses operate on the basis of the second option only.

Either way you can pay a fair price and get a great well done job, or an inflated price and get a rubbish install. If like us you have moved homes often enough you soon learn it is more about good installers and bad installers over any other consideration.

Not that I know the reasons, it seems counter intuitive the outcomes with residential ducted system installations are any different. There are reliable competent installers who do the job properly, and those who are likely to falter. Perhaps the typical residential customers able to afford ducted systems have different needs and expectations.

We tried Daikin directly and two other local independent airconditioning companies. Unhappy with the variety of quotes as to cost and recommended size of unit, then contacted a recommended electrician who was prepared to supply and fit or just fit. He gave me the price of a few units he recommended. I took one of those to a buyers service (Union Shopper) and obtained a price for the unit which was at least $100 cheaper. Electrician was happy to install if I purchased separately and so we did. Its an 8 kW split system inverter, Panasonic unit which was one of only a couple that fitted the available space. It was in for 6 years without trouble but required sealing and regassing just lately.

Using the Choice article I sort detailed quotes from local South Coast companies to remove old, supply and fit 2 new systems Mitsubishi Heavy Industry split systems and the quotes were higher than I expected.
A web search revealed GOLD ie air-conditioning Even paying $90 freight their prices for 2.5 Kw and 7 kw split systems were seriously discounted to the prices in the Choice article and local suppliers. I negotiated with a local company to do the removal and installation and saved 25% overall.
If you are in Sydney or Central Coast you should do better because they will quote to supply and fit systems.
I can drag out the hard figures and delivery times if needed.
As suggested by the Choice article the new units are quieter, more efficient which is showing up in the electricity bills.
I selected one to be 2.5kw system because in times of blackout/grid failure it can be run off a 2.8kw generator. I have in mind that during a 24 hour period I’d switch the generator between the fridge, freezer, washing machine, dryer and aircon. Cheers, John