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

I’m curious about how people go about buying and installing a split-system air conditioner. I’ve had some questions come my way lately on this topic. The options are:

  1. Engage an installer to supply and install the unit.
  2. Buy the unit yourself from a retailer (e.g. Bunnings, or online such as Appliances Online) and then have an installer do the actual installation.

I assume option 1 is by far the most common, but option 2 is perfectly feasible these days, and could be attractive if you have a trusted air con installer to use. I’m not convinced it’s a guaranteed cheaper option though, especially if you factor in your own time and transport costs of buying the unit; also, installers can offer competitive prices for the units themselves.

(Of course, if you have the appropriate licences - electrical, and refrigerant handling aka ArcTick - you can do the installation yourself. I daresay there are more than a few unlicensed DIY installations out there, but let’s not encourage that!)

I’m particularly focused on splits here; wall/window models can be done entirely DIY as long as the right electrical circuit is already in place, and ducted systems really are in the professional-only realm.

Just FYI, DIY-installation split-systems are available in the USA.

Has anyone here gone down the path of buying the split system and hiring the installer separately?


I’m going to be buying a split before next year, I think. I know the size of unit I need, but I am not a bit certain of whether it will be suitable, in terms of the location of either indoor or outdoor units. So I have decided to bite the financial bullet and start getting quotes around August/September from supplier/installers. I just don’t feel confident enough to buy it myself and then find an installer (a refrigeration mechanic? An electrician? Both? Arghhh!)

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My personal experience: a couple of years or so ago I replaced a kaput Teco split with a then-new Fujitsu. I shopped around for the model I wanted and went with an installer who offered a decent price for the unit itself. I didn’t want the hassle of buying it myself then finding an installer.

A CHOICE colleague went the other option recently; he brought the unit directly online, then had a (qualified tradie) mate install it. He provided labour for his tradie mate as well. That plus a mate’s rates deal for the installation is certainly a way to save some dollars, but probably isn’t an option for many people.


We bought a split from a specialist installer company in Dec 2018 because the installation was atypical and 'it ’ had to be seen to be quoted. Buying a bit of hardware and an unknown installation cost seemed a step far for me. The quotes varied by 10% installed, but by just a few dollars on the same model unit. If it was a ‘standard install’ all the quotes would have been within $25 - they all freely commented on their standard install prices.

The company I went with made a mad decision to relocate its business office just before Christmas, the week I was scheduled. The weather gods were disruptive and without a functional head office it got ‘interesting’, but to the company’s credit they got it installed and commissioned before Christmas – on Sunday (!!) 23 Dec. I don’t know if a mass merchandiser with contract installers would pull that off if they had a queue of installs as well as disrupted backlog and a serious ‘push’ to get it done.

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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: