Getting the right size ducted air con can mean the difference between keeping things cool in your home and in your energy bills.

Ducted systems offer convenience because they can deliver consistent cooling throughout a home with a single system. However, the biggest problem that comes up with these systems is when they are not right sized for the space they’re responsible for cooling. Too small, and you’re looking at hot summers and swollen energy bills. Too big, and you’re going to be paying for much more than you actually need in the long run.

But how can you tell what size system your Sydney home needs, and does it really, truly matter when it comes to performance?

Let’s take a closer look together.

What makes a ducted air conditioning unique?

One of the reasons that size absolutely matters in a ducted system is their overall approach to cooling your home. Unlike a split system aircon that’s just responsible for the room that the blower is placed in, ducted systems are required to cool entire homes, if not a bevy of select rooms, making it a much bigger space that requires cooling and dehumidifying throughout the warmer months.

A single compressor and evaporator run the entire system, which delivers cooled air to the specified rooms through an elaborate system of duct work, hence the name. The size of ducted air con comes down to home much power the unit can put out through the air handling unit, which indicates its cooling prowess along with its ability to deliver the air to the designated rooms efficiently through forcing the air along the duct work. Its also a matter of how much power is needed to cool the rooms uniformly since a single system is responsible for cooling an entire home versus a single space.

Because of this, and the fact that every Sydney home has a unique orientation and size, no two ducted systems are necessarily the same. Duct work is custom fabricated to bring air (hot or cold) to the rooms designated through unobtrusive vents in the walls or floors. The air handling unit is (usually) a single unit that is placed outside or in an out of the way place like a basement or utility room. And the right size of ducted air con will be one that effectively meets your cooling needs without under or over serving the space needed.

How to calculate the size of ducted air con

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Now it’s time for a bit of math.

After all, there’s no other way to get an accurate idea of how much power you’ll need in your air con if you don’t know how much space you’re working with.

To start with, you’ll have to calculate how much floor area requires cooling. You can do this by multiplying the width and length of a room to get its floor area. Then add up the floor area for all of the rooms that require servicing. That will be your total area to be cooled. Save that number.

Now consider your ceiling height. Your rooms are not flat spaces, so we need to get a volume measurement. Most homes in Australia have an average ceiling height of 2.7 metre high ceilings.

With this information ready to go, you can do your calculation.

  • If your ceiling height is 2.7 metres: Multiply your total floor area by 0.16
  • If your ceiling height is 2.4 metres: Multiply your total floor area by 0.15

Let’s do an example together. Say your home has a total livable floor area of 95 square metres that you need cool. And your ceiling height is 2.7 metres. That looks like: 95 x 0.16 = 15.2

And what is 15.2? That’s the number of kilowatts your system will need to have in order to effectively cool the area you measured. So you’re looking for a 15.2kW system or something very close to it.

Can I really trust this math?

For the most part, absolutely!

As long as you measured correctly and multiplied like we showed you, you should have an accurate idea of exactly how much power your ducted unit will get.

Except life isn’t like a math problem, and sometimes there are other factors that can affect how much cooling you will, or won’t need.

You might need a little more power for your air con if:

  • Your roof is not insulated (or not insulated very well).
  • You use a lot of space during the day (like work from home).
  • You have a lot of windows that get a lot of sun during the day.

That said, you might need a little less power if:

  • You don’t use a lot of the rooms in your livable areas often during peak times.
  • You have a highly insulated and energy efficient home.
  • You have a well-ventilated roof system.

Why the right size of ducted air con really matters

Aside from not keeping the temperature quite right and leaving you and your family either way too hot or much too cold, what does it really matter if your air con is not quite the right size of ducted air con?

Actually, this can affect more than you might realise. For example, proper cooling also addresses the humidity in the air, which can cause mould and mildew, unpleasant smells, and even cause damage to everything from the wallpaper to your electronics.

Undersized air cons will leave the home never quite cooled off, which also means that your system might never stop running on the hottest of days. Not only does that mean discomfort but also extra wear and tear on your system, which can shorten its lifespan, and higher energy bills.

Oversized air cons face similar problems with longevity, though you might not expect it. That’s because these units will turn themselves on and off with short cycling, which can wear out the parts in the system much more quickly than normal usage.

Wondering if you can DIY your installation? Find out here

Choose the best ducted air conditioning provider in Sydney

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Of course, there’s something to be said for having experience in an area of business to help customers make the best decisions. And when it comes to choosing the right size of ducted air con system for your home, no one will be better at helping you than HunterCON. Our experienced team has been helping Sydneysiders keep cool for over 10 years with licensed electric and air con specialists on staff and ready to consult with homeowners.

We’ll help you do the math on your house as well as the less tangible factors that can affect the temperatures in your home to choose the right size unit for your cooling needs. And every project comes with a 5-year installation warranty so you don’t have to worry about keeping things cool moving forward.

For a fast free quote including an estimate on your system size, call us on 02 8283 1105 or request assistance online today!