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What is zoned air conditioning and how does it work?

Ducted air conditioning zones

For countries with scorching climates like Australia, air conditioning is a godsend that has become increasingly popular in the last few decades. A government report² from ten years ago found that three out of four Australian households had some form of air conditioning, a number that is likely to be even higher today.

Air conditioning comes in a wide range of systems, from small portable units designed to cool a single room, to expansive ducted systems that cover an entire property. In this article, we’ll be discussing zoned air conditioning—how it works, its main components, and the pros and cons of this type of system.

How zoned air conditioning works

Zoned air conditioning is achieved when a ducted air con system is divided into areas (or “zones”) which can be cooled or heated independently. It consists of a series of ducts in your roof, which channel air to the various zones in your home. Zones are usually defined by the main living areas of the house, but if you wanted greater control, you could have a zone for every separate room or area.

To create zones in the ducted air conditioning system, ducts must be extended to each unique area and end in an outlet vent where the air is released. To control the airflow of the zone, electrical mechanical valves called dampers are used, with the intensity of the airflow controlled by how much the damper is open. When it’s fully open, the maximum amount of airflow is allowed into the zone, and when it’s fully closed, the zone won’t be receiving any conditioned air. Most zoned air con systems offer varying degrees of airflow for every zone, giving you fine control over the system.

Zoned air conditioning components

A zoned (ducted) air conditioning system has a number of important features and components:

Indoor unit

Usually installed in the roof cavity, this is the main unit that delivers cool or warm air to your home. It’s made up of a heat exchange coil, a fan, filters, and a  Remote Thermostat/Control.

Outdoor unit

This is installed outside, and works with the indoor unit to pump refrigerant between the two units, in addition to rejecting the heat gathered from the indoor unit. It’s made up of a compressor, heat exchange coil and fan. 

Vents 

Air is delivered to each zone through ceiling vents, which come in a range of designs to suit your property.

Zones

Zones are the areas of the property where you want to control the climate, which can be adjusted individually.

Control units 

The air conditioning system is controlled through a centrally located wall-mounted unit controller, and zone controller. Some advanced systems have individual controls in each zone and even allow you to control the climate through your smartphone or tablet.

Sensors 

Sensors measure the temperature of each zone, to regulate the temperature effectively.

Dampers

Dampers (also known as zone motors or volume control dampers) control the amount of airflow into a zone.

Advantages of zoned air conditioning

Energy efficiency

For bigger properties with a large amount of space to cooled or heated, ducted/zoned air conditioning is more efficient compared to a split system with individual units¹

Zoned air conditioning allows you to control the airflow for different areas of the house, which can be shut off for areas that aren’t being used, to save electricity. Many manufacturers (e.g. Daikin) will allow you to set timers for individual zones too, so that you can control the climate to your family’s exact schedule, saving even more money.

In a regular ducted air conditioning system, every kilowatt of electricity creates three or more kilowatts of cooling or heating capacity, but this can vary depending on the energy star rating. To estimate running costs, we can consider the following situation:

  • 20kW ducted air conditioning system, with four zones
  • 10kW average output
  • 21c/kWh electricity cost
  • 500 hours running time per year

With these numbers, the air conditioning system uses 5000kW per year, which at a cost of 21c per kWh, comes to a total of $1050. It’s important to note that this is a rough estimate which that will vary depending on the energy efficiency of the main unit.

Discreet and quiet 

The main cooling unit for a ducted air conditioning system is tucked away in the roof (or under the floor), which makes it much more quiet and subtle than a split system. If you’d like a discreet climate control system that creates a peaceful, quiet environment, then ducted air conditioning is the way to go.

Improved health 

Ducted air conditioning removes dust particles and moisture from the air, which helps people with weak immune systems and asthma. It’s also a healthier choice for the elderly and young children.

Disadvantages of zoned air conditioning

More expensive to install

Zoned air conditioning is more expensive to install when compared to a simple split system. It usually covers a larger surface area, which requires a higher capacity cooling unit, and more ducts and air vents to be fitted. But though the system has an initial higher cost, its higher efficiency means that you’ll end up saving money over time when compared to a split system.

Unsuitable for some buildings

The main cooling unit for a ducted air con system is usually placed in the roof or under the floor of the building, but if neither the roof or floor have cavities large enough to fit the unit, an alternative conditioning system must be considered.


Air conditioning has become an essential part of everyday life in Australia, particularly in the hotter parts of the country. For property owners looking to invest in an air conditioning system for their home, zoned air conditioning is one of the most sought-after solutions, offering climate control that is energy efficient, discreet, and with a high level of control over their own comfort.

References

  1. Rob Schneider, 2020, Ducted Air Conditioning vs. Split System, Hi Pages
  2. 2014, Environmental Issues: Energy Use and Conservation, Mar 2011, Australian Bureau of Statistics

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