Why Your Ducted Air Conditioner Might Not Be Working as It Should

You’ve had ducted air conditioning installed, but something’s not right. One room’s freezing, another is barely touched, and the system seems to run for hours without doing much. These are common issues — and more often than not, they come down to one small but crucial detail: the setpoint.

At Artarmon Air Conditioning, we regularly investigate underperforming ducted systems. One of the most common causes we find? Poor sensor placement or limited zone control.

What Is a Setpoint?

A setpoint is the temperature you ask your system to maintain — usually set via your wall controller. If you set it to 22°C, the system runs until it senses that this temperature has been reached.

But the system can only respond based on where that temperature is being measured — and that’s where things often go wrong.

Where Is Temperature Measured?

Most ducted systems measure temperature from either:

• The wall controller, or

• A sensor located in the return air grille

In many homes, the return air is installed in a central hallway — and that hallway typically doesn’t have any nearby supply vents. It’s a dead zone for airflow, and it tends to stay warmer in summer and cooler in winter compared to the rooms you’re actually using.

That means the system may run for far too long trying to hit a target temperature in a space that isn’t being directly heated or cooled.

Why It Matters

When your air conditioner is measuring from the wrong place, the result is poor comfort — and high running costs.

• Rooms feel too hot or cold despite the system running

• The system runs longer than necessary, spiking your power bills

• You constantly adjust the controller to try to fix it — but it never quite works

• Your system wears out faster from overuse

What Needs to Be Done

Unfortunately, setpoint and zoning issues aren’t something homeowners can resolve themselves. To fix it properly, Artarmon Air Conditioning needs to inspect your system and assess what options are available based on your setup and controller.

Depending on the system, we may be able to:

• Reconfigure the system to use a more accurate temperature sensor (e.g. at the controller instead of the return air)

• Install a remote temperature sensor in a key room like your lounge or bedroom

• Upgrade your controller to something more advanced

• Install a smart zoning system like AirTouch, which gives you full room-by-room control, better temperature sensing, scheduling, and app-based control

We’ll walk you through the options and only recommend solutions that are genuinely worthwhile based on how your home is laid out and how you use your system.

Ducted air conditioning should be efficient, quiet, and comfortable — but if your system doesn’t seem to be keeping up, it might not be the unit itself that’s the issue. It could be the way it’s reading and responding to temperature — and that’s something that can be fixed.

At Artarmon Air Conditioning, we’re here to get your system working properly — not just ticking boxes. Whether it’s relocating a sensor, reconfiguring airflow, or installing an AirTouch system for smarter zoning, we’ll give you honest advice and long-term solutions.

Want your ducted AC to actually work the way it should?
Book a diagnostic visit and let us take a proper look.