CHOICE membership

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

My preferred strategy. But only because of where we live.

Have done this for 3 instances (MHI x 2, Fujitsu x1) in the previous 5 years plus once used a specialist (Daikin) to supply and install.

For anyone in a big city with numerous companies specialising in air conditioning systems, it may be competitive to shop around for a one stop supply and install from a local specialist. It is worth noting the specialist installers usually have a preferred brand and likely price advantage with that brand for their area.

We did one install two years back and another this time last year. In both these instances we managed to purchase MHI splits. Choice reviews are very helpful. Also scored due to timing discounted pricing plus MHI cash backs. The Goodguys in one instance and surprisingly for the other on a hot tip from the MHI distributor rep, Bunnings. We priced the same units including supply and install from a number of suppliers and specialists to confirm we had the best prices.

As none of the suppliers were local 30-50km distant we paid for delivery in one instance and picked up from Bunnings in the other.

We have several local electrical contractors who have refrigeration licenses (dual trade). The difference in quotes between them has been minimal. Also easy to obtain reliable quotes as there is minimal travel required for them to check the job out. We have used our locals both times. In the instance of warranty, if it is an install fault they fix. If it is a unit fault usually they charge us only time to drop in. $100 call out for a 2km drive on the way past to home seems a little rich. We have never needed to make the next call to the retailer for an aircon, so that remains untested. Although the further you are from their nearest service agent the more likely they are to talk to your installing electrician and do a deal. Have experience of that first hand on other items.

It is worth considering any new install will require electrical cabling and work in the household meter box. Getting the power cables to the air con location can be a big part of the labour cost and challenging for some homes. It is worth noting some specialists and the retailers such as HN, the GG etc quote a standard install price (with a list of exclusions/variations). Their install quotes always seemed a little cheaper. We were not game enough to dip that toe in the water.


Very useful information - thank you. I am intending to purchase soon - would appreciate detail of the timing of the discounts: am assuming it is probably related to end of season and/or new model rollout…??
Have been watching the catalogues/CHOICE tests for a couple of years & managing the heat the old fashioned way (ie < AC), but it is time to bite the bullet…

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I looked into this recently and have some connections who are fridgies …

Essentially I stayed with evap and partially rebuillt my own evap - circumstances were not relevant to this topic entirely.

The relevance for me was this - having an installer recommend a product seemed loaded with things like kick-back and product margin and that seemed quite apparent when asking certain installers whether they could supply ‘product X’ - no, ‘we use product Y’ … Having connections who were fridgies dissolved this illusion and took me to what ‘seemed like’ a more honest approach. Of course that still had a good does of ‘opinion’ but it came from people who had the coal-face experience and more to lose than just a sale if they did me over.

There is also the sense that one can pay more for the install if there is no margin in product sale. This has to be balanced against the buying power of ‘Big Corp’ vs the local guy. Big buying power can save a lot - or sometimes not.

It seems like a minefield if you don’t have contacts … but what industry isn’t like that?


We always do that.

We use the most professional installer and service person we have ever come across to install replacement units and service existing ones, and when he finishes the job, they are alwys working perfectly.

In comparison, the cowboys we had install 3 Fujitsu inverters at our previous residence failed to ensure the PVC conduit drain pipes actually sloped downhill and muck would build up until water would flow down the inside walls.

Our current person found the problems and rectified the installations.

He also sells residential and commercial aircons to anyone who wishes to buy from him but he does not expect anyone to buy from him and will say to go get the aircon and call him afterwards to have them installed.

I expect he would not make much on the sale of an aircon and he is obviously better off getting well paid for professional installations.


When getting initial quotes I found the ‘standard installation price’ was predicated on the outside unit being mounted on the wall ‘behind’ the inside unit. It included piping for that scenario and a mounting footer that went onto the exterior wall. The ‘standard’ electrical work was a maximum distance to the breaker box as a wire could be run, and a standards conforming breaker box with an open position for the additional switch. Anything deviating would be additional costs.

In my area the vast majority of A/C units seem to fit that, although the electrical work is not so obvious, especially in older houses. If one has an ‘old school’ wire fuse box it will usually need to be brought up to standard for anything to be added - think $1,000-1,500 although those costs can be minimised by doing only the bare essentials rather than doing it ‘right’ for the future.


I suppose the other purchase option is to select the preferred split system and then find a installer which can supply and install the preferred system. It is a bit of a mash of option 1 and 2.


I did my (Choice) research and the CSIRO calculations and chose two Mitshubishi Heavy, Split System Inverters. I found that various installers only dealt with certain brands. It took another year to have them installed. We were not in a rush, as we were not buying their brand we took our place at the end of the queue. Our installer was a mate of the electrician who wired our place. The deal was quite reasonable, although he had to come back to rectify some work as he was suffering from sleep deprivation at the time and messed up a couple of things.

The installer said he would have put a much larger system in the lounge, however the CSIRO calculations have proven correct for the sized unit I bought, thus saving me over $1,000.

  1. You may have to use the installer’s brand and size choice.
  2. If you buy your unit, it might be difficult to get an installer

I bought my first split system from Saverys and installation was included in the price. The installer made a real mess of the job, leaving ugly cables visible down the front of the house. I was told that because installation was included, and because the job was ‘difficult’, I just had to put up with it. I’m sure the installer simply took the cheapest and easiest alternative because he was being paid a set price for the job. My next system was installed by a local tradie whom I had used several times for repairs. He got me a special deal from the manufacturer (whom I contacted directly). The system was delivered free of charge and installed the next day. The tradie did a wonderful job for a price that was similar or less than other quotes that I received. I would definitely go the tradie route in the future.


That reflects my experience. I had all ‘on site quotes’ and 2 of them said I needed two systems totalling 14.5KW; 2 of them said no worries with 1 at 9.4KW. The latter was installed and is adequate to keep it ‘too cool’ even on 44C days. The former used industry equations for area, ceiling height, windows, and insulation; the latter used their experience.

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Whilst the larger model/s may cost a little more, they may not be working as hard as the smaller units thus reducing power usage, which may actually to be more economical in the long term.


With regard to power consumption, ours doesn’t use much. Our power often goes off (rural SWER line) so we have the house wired for generator power (start it, plug into the switchboard). The generator can’t handle the stove or dishwasher and struggles with the microwave and electric kettle. Mr Z absent-mindedly started our largest split system and the generator didn’t even change tune. He was impressed! We now use it more often, mainly to reduce the humidity and have it set at 27 degrees, or at least 10 degrees below outside if it is high 30’s or 40’s. We did have an old portable air-con, but the power consumption was like boiling the kettle all day.


Great conversation - thanks everyone. The conclusion so far is that it can be well worth buying the unit yourself and engaging an installer separately, provided that you have a trusted and willing installer to work with.

Also, it’s good to have some more evidence that there’s a tendency for installers to quote for larger capacity than necessary (though @Fred123 does make a good point that a larger model won’t have to work so hard, which may be a long term benefit. My view, as I’ve said in the CHOICE buying guide, is that you do the sums and choose a model with equal or slightly greater capacity for the room.)


My cousin who is a Refrigeration & AC mechanic (who works on both commercial and residential systems) often is one who uses the calculations to determine capacity. If it is either too large or too small they become inefficient. Too small they run almost constantly and often do not control the temp well, too large and they over cool too quickly so often it bounces between too cool and as it slips below desired temp it over cools again which runs up a bigger bill than needed. My family now always get him to calculate capacities needed and have always found the units then chosen based on that to be the best economy of use. We have had other installers when he couldn’t be used that guesstimated the capacity and we often found those not the best decisions after a period of use. In those bad cases sadly a waste of good money.

Proper calculations take into account the direction walls face, what the walls are made of, and insulation used as well as dimensions to establish a range of values for appropriate AC sizes. There will be an upper and lower limit (not a big difference eg 6 to 7 kW) so often getting something towards the middle to account for unexpected outside temp ranges is probably best.

NB These calculators are produced by the AC industries and some can be obtained for free but others are only available to those in the industry.


Is it possible to access the format your cousin uses, in a simple “for dummies” version please?


Some examples have been added to my post above. Try to avoid those that calculate just on room size alone as they do not take into account insulation, sun direction and thus impact on walls, and they do not account for wall construction materials eg brick vs wood.

From the Mitsubishi Heavy Industry pdf this is their recommendation “MHIAA recommend a heat load survey should be conducted by a licensed air conditioning installer”, the ranges they give in the pdf are based on general recommendations so are a guideline if you don’t get the survey done.


This is the size calculator I’ve used in the past:


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.