How Ducted Air Conditioning Works in Melbourne Homes

If you’re a homeowner in Melbourne, you’ve probably considered upgrading your home’s climate control from outdated ducted gas heating to ducted air conditioning. Naturally, there’s going to be a learning curve when switching from gas heating to electric heating and cooling. In this post, we’ll discuss how ducted air conditioning works, and whether it’s the right choice for your Melbourne home.

What Is Ducted Air Conditioning?

Ducted air conditioning is a whole-home climate control system that uses a network of ducts hidden in your ceiling or under the floor to distribute conditioned air throughout your entire house. Unlike split systems that heat and cool individual rooms, ducted systems provide central heating and cooling from a single outdoor unit and indoor unit, delivering consistent temperatures across multiple rooms or zones.

The beauty of ducted systems is their discretion. You won’t see bulky wall-mounted units in every room. Instead, you’ll only notice subtle vents in your ceiling or floor, while the main components work quietly out of sight. This makes ducted air conditioning popular for Melbournian’s building new homes, or renovating existing ones.

How Ducted Air Conditioning Works

At its core, ducted air conditioning uses the same refrigeration cycle that keeps your fridge cold. It’s based on a simple principle: when a liquid evaporates, it absorbs heat, and when a gas condenses back into a liquid, it releases heat. By manipulating this cycle, your ducted system can either cool or heat your home using electricity.

Here’s how the refrigeration cycle works in ducted air conditioning:

Compression

The process starts at the outdoor unit, where a compressor pressurises refrigerant gas. When you compress a gas, it heats up (just like how a bike pump gets warm when you’re inflating a tyre).

Condensation

This hot, high-pressure gas flows through the condenser coil in the outdoor unit. As Melbourne’s outside air flows over these coils, the refrigerant releases its heat to the outside environment and condenses into a high-pressure liquid. This is why you’ll feel warm air coming from the outdoor unit on a hot day.

Expansion

The liquid refrigerant then passes through an expansion valve, which suddenly drops the pressure. This is like releasing air from a compressed can. The refrigerant becomes extremely cold as it expands.

Evaporation

This cold refrigerant enters the evaporator coil located in your indoor unit (typically in the ceiling space). As warm air from your home is drawn over these cold coils, the refrigerant absorbs the heat and evaporates back into a gas. The now-cooled air is then pushed through the ductwork and into your rooms.

The cycle then repeats, continuously moving heat from inside your home to outside (in cooling mode) or reversing the process to bring heat inside (in heating mode).

The Different Parts of a Ducted Air Conditioning System

These are the main parts of a ducted air conditioning system and how they work together to heat and cool your home:

Outdoor Unit

This houses the compressor and condenser. In Melbourne homes, you’ll typically find this mounted on a concrete slab beside the house, on the roof, or occasionally tucked away on a side return. It’s the part that does the heavy lifting of actually heating or cooling the refrigerant.

Indoor Unit

Hidden in your roof space or under the floor, this contains the evaporator coil and a powerful fan. It’s responsible for cooling or heating the air and pushing it through your ductwork.

Ductwork

A network of insulated ducts that distribute the conditioned air throughout your home. In most Melbourne homes with existing ceiling space, these ducts are installed in the roof cavity. Two-storey homes require special consideration for ducted air conditioning installation, with ductwork running through bulkheads or internal walls to service the ground floor.

Supply Vents

These are the grilles you see in your ceiling or floor where the cooled or heated air enters each room. Modern systems allow you to close vents in rooms you’re not using.

Return Air Grille

Usually a larger grille centrally located in your home (often in a hallway), this is where air is drawn back into the system to be reconditioned. Think of it as the system “breathing in” your home’s air. It is sometimes located vertically on a wall also.

Thermostat/Controller

This is your command centre. Modern ducted systems use sophisticated HVAC controllers that let you set temperatures, create zones, and even schedule operations.

Zoning Dampers

Inside the ductwork, motorised dampers can open and close to direct airflow only to the zones you want to heat or cool. This is essential to avoid heating or cooling unused spaces and helping with energy efficiency.

What We Consider When Installing Ducted Air Conditioning in Melbourne Homes

Melbourne has a diverse selection of homes that never ceases to challenge us – a bit like the weather! Here are some things to keep in mind when considering installing ducted air conditioning.

Roof Space

Most Melbourne homes have excellent roof spaces for ducted system installation. Edwardian homes (1900s-1920s) like those throughout Brunswick and Northcote, Victorian-era homes (1840s-1900s) common in Carlton and Fitzroy, and Californian bungalows (1920s-1930s) prevalent in Coburg and Essendon all feature pitched roofs that provide ample room for the indoor unit and ductwork. This makes installation relatively straightforward compared to homes with flat roofs or limited ceiling cavity space.

Home Insulation Makes a Difference

Melbourne’s temperature variations means good home insulation is vital. It also has a big impact on how efficiently your ducted system operates.

If your roof space is lacking proper insulation batts, your ducted air conditioning will work overtime trying to combat heat gain in summer or heat loss in winter. The Australian standard measures insulation effectiveness using R-values. The higher the number, the better the insulation. For Melbourne’s climate (Zone 6), ceiling insulation of R4.0 to R6.0 is recommended.

If you’re installing air conditioning in Melbourne and your ceiling has poor or no insulation, it’s worth adding quality batts like polyester or glasswool at the same time. Good ceiling insulation can reduce your cooling and heating costs by 45-55%, meaning your ducted system won’t have to run as hard or as long to maintain comfortable temperatures throughout your home.

Zoning for Melbourne’s Layout

Many inner Melbourne homes have the classic layout of living areas at the front, bedrooms down a central corridor, and kitchen and dining at the rear. Zoning your ducted system to match this layout means you can cool or heat the bedrooms at night while keeping the system off in the living areas, or vice versa during the day.

Reverse Cycle Capability

Melbourne’s cold winters make reverse cycle air conditioning essential. The same system that cools you during those 30+ degree February days efficiently heats your home during June’s frosty mornings. The refrigeration cycle simply reverses direction, pulling heat from the outside air (yes, even cold air contains heat energy) and bringing it inside.

Suitability for Your Home Size

Ducted systems make most sense for homes over 100 square meters. For apartments, smaller homes, or terrace houses, individual split systems or a multi head split system installation is worth considering.

The Benefits of Ducted Air Conditioning for Melbourne Homeowners

Whole-Home Comfort

Unlike portable units or single split systems, ducted air conditioning provides consistent temperatures throughout your entire home. No more hot spots in the back bedroom or freezing when you move from the living room to the hallway.

Aesthetics and Property Value

Melbourne’s inner suburbs are full of period homes and character properties where maintaining aesthetic appeal matters. Ducted systems are virtually invisible from inside the home, preserving your interior design and architectural features. This discretion often adds more value to your property than visible wall-mounted units.

Take a look at a recent air conditioning installation in Essendon below. During this home renovation, the owners wanted a discreet upscale look that complemented the period features of the home:

Zoning Flexibility

With a correctly zoned hvac system, you’re not locked into cooling or heating your entire home. Run just the bedroom zone overnight, or just the living areas during the day. This flexibility is valuable in Melbourne’s variable spring and autumn weather when you might only need climate control in parts of your home. It also helps with energy efficiency and keeping your bills lower.

Quiet Operation

The noisiest components (the compressor and outdoor fan) are located outside your home. Inside, the system operates quietly, with just the gentle sound of airflow through the vents. This is a significant advantage over window units or even some split systems.

What Ducted Air Conditioning Costs in Melbourne

Upfront Investment

Ducted systems require a higher initial investment than split systems, but also attract the biggest VEU rebates on offer when replacing ducted gas heating.

At ExtrordinAir, we offer a basic Hisense 12.5kW ducted aircon installation from $6595 after VEU rebates have been applied. Our most popular ducted offer is a Panasonic 18kW ducted installation, priced from $13,795 (also after rebate).

Why such a price difference? Panasonic is a premium brand with Japanese engineering. It has built in air purification, is a larger system (18kW vs 12.5kW), includes 6 zones (whereas the Hisense has no zoning), 10 outlets (vs 6 for the smaller Hisense system). Panasonic also has smart temperature sensors and a premium iZone wall controller with WiFi connectivity allowing you to control your ducted air conditioning from an app on your phone.

If you need to finance your ducted air conditioning system, we also offer interest free air conditioning packages.

Running Costs

Modern ducted reverse cycle systems use inverter technology and heat pump principles that make them remarkably efficient. These systems have a Coefficient of Performance (COP) typically between 3 and 4, meaning they produce 3 to 4 units of heating or cooling for every unit of electricity consumed. This makes them more efficient than traditional gas heating, which has a COP of around 0.9, or electric resistance heaters with a COP of 1.

For a mid-sized ducted system (around 16-20kW cooling capacity) serving an average Melbourne home, the actual power input will be approximately 5-7 kW. Based on Melbourne’s current electricity rates of 25-35 cents per kilowatt-hour, expect running costs of approximately $1.50 to $2.50 per hour.

Running the system for 6 hours daily throughout summer (December to February – 90 days) could cost around $800 to $1,350 for the cooling season.

Many Melbourne homeowners are also choosing to install solar panels to offset electric heating and cooling costs during daylight hours.

While zoning helps manage energy use by cooling or heating only occupied areas, the key to controlling costs is strategic operation. Setting thermostats to moderate temperatures (24-25°C for cooling, 18-20°C for heating) makes a big difference. Every degree cooler in summer or warmer in winter can increase energy consumption by up to 10%.

It’s worth noting that evaporative cooling systems have the lowest running costs overall (around 20 cents per hour). As they only provide cooling and work best in dry conditions, they are less versatile than reverse cycle systems for Melbourne’s variable climate.

Maintenance Costs

Ducted air conditioners require regular servicing. We recommend budgeting $250-$350 annually for a professional ducted air conditioning service. This includes:

Cleaning the housing
Cleaning and flushing the evaporator
Flush of the internal draining system
Cleaning of air filters
Sanitising and deodorising the evaporator
Cleaning the condenser coils
Checking the outdoor pipe insulation and replacing if needed
Removal of any vegetation around the outdoor unit
Checking the fan for any obstructions
Pressure testing of refrigerant gases and airflow
Testing the wall controller and running the system

cleaning and servicing a ducted split system air conditioner in keilor east home

Is Ducted Air Conditioning Right for Your Melbourne Home?

For Melbourne homeowners with adequate roof space, period homes where aesthetics matter, or larger properties requiring whole-home climate control, installing ducted air conditioning offers modern comfort and discretion.

The ability to zone different areas, provide both heating and cooling, and maintain your home’s aesthetic appeal makes it very well-suited to Melbourne’s inner suburbs. While the initial investment can be higher than other options, the combination of property value increase, energy efficiency through zoning, and year-round comfort makes ducted air conditioning the most popular choice for Melbourne homes.

If you’re considering ducted air conditioning for your Melbourne property, consult with our team at ExtrordinAir. Located in Melbourne’s Airport West, we are within easy reach of western suburbs, inner north and north east Melbourne. Serving our community for 20+ years, you can rely on honest advice, expert installation from our licensed trades, and 6 year guarantees on all new installations.

Let us help you design a system that keeps you comfortable through all four of Melbourne’s seasons, even when they all happen on the same day!