What is a multi-split?

Multi Split systems consist of one outdoor unit running multiple indoor units


We are often asked about installing multi split system air conditioners. Most people who have not yet done their research are quite rightly under the impression that they will be saving on cost compared to the price of buying multiple single head systems.

Makes sense. Having less out door units should save on cost right?

Well, that is not the case.


Check out our multi-split system installation video. It will make clear why these units cost more to install.



You can get an online air conditioning quote here


Lets look at a price example,

mutli split system installation


Mitsubishi Electric brand – multi split system option

You want air conditioning in 4 bedrooms

4 x 2.5 kw MSZGE25VA indoor units

1 x 8.0 kw MXZ-4D80VA outdoor unit

Unit prices excluding installation – $4960 inc GST


Mitsubishi Electric brand – single split system option

You want air conditioning in 4 bedrooms –

4 x 2.5 kw MSZGE25VA  indoor units

4 x 2.5 kw outdoor unit

Unit prices excluding installation – $3915 inc GST

Difference in price – $1045 inc GST


As you can see the product it self is more expensive to have what seems to be three less out door units. Why?

Is it possible that manufactures charge more for the multi-splits because it is a “specialty item”?  Multi splits generally cannot be purchased through bulk stores such as Harvey Norman or the Good Guys.

Is it possible that the single head units sell much more than multi splits making them cheaper to manufacture?

Either way, a multi split will cost you more to buy, and we haven’t even factored in the installation yet.


Why does the installation cost more?

Well, this answer does make some sense. With a single head split the most cost effective way to install the air conditioner is  back to back.

A nice simple install. Indoor unit is located on an external wall and the outdoor unit sits directly behind it on the ground. Generally no more than 3 meters of pipe, electrical and duct cover is needed. This can vary depending on your particular situation but it is a price starting point.

Essentially, the closer the indoor unit is to the outdoor unit the cheaper the costs will be.

But with a multi split system the outdoor unit needs to be located hopefully in a central point in relation to the locations of the indoor units. So if 2 or even 3 indoor units are located on the other side of the house for example, that is going to add costs. The pipes would most likely need to be ran through a pitched roof or even more expensive, through a flat tin roof ( see video on this page).

As a guide, extra pipe is charged around $60 per meter


Lets look at an example,

3 x indoor units with an extra 8 meters of pipe per unit at $60 per meter.

8 x $60 = $480

3 x $480 = $1440

Difference in price – $1440 inc GST


Installation costs $1440 more and the multi units cost $1045.

Total extra cost to install multi-split system – $2485

Of course this is a guide only. Split system air conditioner installations have many factors depending on each unique situation, but you get the idea.


Combinations of multi splits:

Multi splits allow a combination of KW sizes to connect to the outdoor unit.

Some brands allow up to 8 indoor units to be run off one outdoor unit. What you need to do is very simple when deciding what size outdoor unit you will need.


2 x 2.5 kw indoor units will need a 5.0 kw outdoor unit

3 x 2.5 kw indoor units will need around 7.5kw outdoor unit

1 x 2.5 indoor and 1 x 5.0 kw indoor will need around 7.5 kw outdoor unit


Also, if you were to use 4 x 2.5 kw indoor units to service 4 bedrooms you could use an 8.0kw outdoor unit

But 4 x 2.5kw = 10kw…… I hear you say.

If all 4 units are running at there maximum capacity, the out door unit will give each unit only 2.0kw of output. But generally speaking, the indoor units are rarely running at full capacity. Plus, you may only need to run 3 units most of the time. Maybe the 4th unit is in a spare room and only need from time to time.


Pros and cons of multi split systems.


  • Only requires one outdoor unit.

Particularly handy for people who live in apartments and literally don’t have space for any more than one outdoor unit.


  • If the outdoor unit ever has a problem and stops working, all the indoor units will stop working too.

If this happens in summer, having separate units will mean you will at least have air conditioning units working while waiting for a service.

  • Costs more to buy and install.