Multi Head Split System Air Conditioners May Not Be Best

Reverse cycle split system air conditioners are a popular choice for cooling.

They are also one of the cheapest heating systems to run.

Single Head Split System

These are the most common units, that you will see in most big box electrical stores, consist of a matched outdoor unit and an indoor unit.

Fine if you want the cooling in one room, but it can look a bit messy with lot’s of outdoor units if you have got several rooms to cool

There is however an alternative

Multi Head Split System

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

In some cases up to 8 indoor units to be run off a single outdoor unit.

The indoor units don’t have to be all the same KW capacity so they can be matched to the room size

The outdoor unit can also be a little smaller than the sum of the indoor units

For instance if you had a 3 bedroom house you may have 2 x 3.0kw indoor units in family rooms and 3 x  2.0kw units in the bedrooms a 10.0kw outdoor unit may be adequate/

If all 5 indoor units are running at maximum, the out door unit will only deliver 11kw of output rather than 12kw.

However the indoor units are rarely all running at full capacity,

Also most people are unlikely to run all 5 units at the same time.

Advantages and Disadvantages of Multi Split system


  • Good for people who have limited space
  • Much neater than having several units


  • If the outdoor unit fails all the indoor units stop and you have no cooling.
  • Usually costs more to buy and install.

Why are Multi Head Systems more expensive?

Although it seems that having less out door units should save on cost there are a few reasons why that isn’t the case.

  • With the majority of systems being single head systems that makes multi head systems a special order.
  • Multihead systems are normally sold by specialist companies rather than the big box stores so there is less competition.
  • Longer pipe runs and cable runs are required rather than the typical back to back installation of the single head systems.
  • In some cases the indoor units might also require drainage pumps rather than a simple gravity drain through the external wall.