2 storey houses: 1 air/con unit or two?

Hi guys

We are thinking of getting two air/con units. One for each floor. I know it will cost more initially but it would save money in the long run, right? What do you guys think? Is it worth having two or would you just get the one?

How large is the double storey house in terms of area?

Ground floor = 178sqm and the upper floor is 150sqm

thats a big house.

Automatically I would be going for the biggest three phase unit(maybe 21kwatt i think). Just have one, and then have zoning to reduce the cooling area and to save on running costs.

Thanks for that borg

Sorry, just to confirm.
If for example the air con is on in every single room, it uses $5 per hour. Does this mean that if only 50% of the house is being cooled it will only use half of $5?

for the brivis add on units the output of cool air for example is\ either on or off. If you close half the house or one zone for example, the house will cool down about twice as quick. Therefor unit turns off much earlier and runs for a less percentage on the house. So yes it easily could reduce running cost. Definatley worth doing as refridgerated is expensive to run.

In situation like this we quote on either one ducted unit for around $16K or two smaller separate units for around $22K total. 2 units works better as each unit is smaller, and you can really choose what you want to run. If you have only one big unit, you will need to run lots of outlets at once. For example, you cannot just run your master bed as the airflow to this room mill be too much. With the smaller unit this is less of a problem.

If you have the money the 2 separate units are a better option.

Thanks for that TheBoatMan

Which one were your prices based one? How about a Daikin? How much would you normally quote?