How Much Does Heating Duct Replacement Cost in Melbourne?
Your gas ducted heater works hard through a Melbourne winter. The ducts behind your ceiling vents work just as hard. They carry warm air from the heater to every room in your home. Over the years those ducts can sag, leak, or age out of their best condition. When that happens, a duct replacement brings your warmth back and can lower running costs too.
How much heating duct replacement costs in Melbourne depends on the size, insulation quality, and length of ductwork needed. We’ve put together this guide with some pricing estimates.
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What Does Heating Duct Replacement Cost in Melbourne?
Most Melbourne homeowners pay somewhere between $1,400 and $5,600 to replace the ductwork on an existing gas ducted heating installation. The figure is based on:
- The size of your home
- The length and number of duct runs
- The quality of the duct you choose
- How easy the roof space or subfloor is to reach
A fresh ductwork install in a home that has never had ducts sits a little higher, often $2,400 to $6,600, because the job adds plenums, distribution boxes, and new outlets from scratch.
Here is a quick snapshot to help you budget.
| Job | Typical Melbourne price range |
|---|---|
| Duct inspection or assessment | $40 – $100 |
| Single duct run replacement | $270 – $500 |
| Full ductwork replacement (existing system) | $1,400 – $5,600 |
| New ductwork install (home with no ducts) | $2,400 – $6,600 |
These ranges are a guide. The honest answer for your home comes from an onsite assessment, where we measure your runs, check your roof space, and match the duct to your heater. At ExtrordinAir, we are happy to provide a free quote.
A full replacement usually takes one to two days. Good ductwork then serves you well for 10 to 20 years.
Why the Price Range Varies
A duct replacement is more than a length of silver tube. The price reflects a full system of parts working together:
- Insulated flexible duct runs from the heater to each room.
- Plenums and distribution boxes split the airflow evenly across the home.
- Fittings, reducers, and dampers balance the air so every room warms at a similar pace.
- Register boots and ceiling vents deliver the warm air where you want it.
- Labour to remove the old ducts, fit the new system, seal every joint, and test the airflow.
Tidy workmanship is where a lot of the value sits. Sealed joints, properly strapped runs, and balanced airflow keep the heat moving to your rooms rather than escaping into the roof.
R Ratings & Duct Quality
Duct insulation is measured by its R rating. A higher R number means stronger resistance to heat loss, which keeps more warmth inside the duct on its way to your rooms. The common tiers in Australia are:
- R0.6 – the lightest option, suited to mild settings and short runs.
- R1.0 – a strong everyday choice for Melbourne heating ducts.
- R1.5 – the standard for many new installs, and the pick for ducts that handle both heating and cooling.
- R2.0 – premium insulation for long runs, exposed roof spaces, or homes wanting maximum efficiency.
Melbourne sits in climate zone 6 under the National Construction Code. For heating ducts, R1.0 insulation is the usual baseline. Ducts that carry both heating and cooling step up to R1.5. Choosing a higher R rating adds to the upfront price. In turn, you generally get lower running costs and steadier room temperatures year after year.
Quality also shows in the duct material itself:
- Insulated flexible duct is the everyday choice for Melbourne homes. It is light, quick to fit, and available in every common size. Look for products that meet AS4254, with insulation rated to AS/NZS 4859.
- Semi rigid aluminium duct holds its shape and allows smooth airflow. It suits tight or awkward spots where a fixed form helps.
- Sheet metal duct is the most durable option and the most costly. It is common in commercial work and premium home builds.
When you compare quotes, check the R rating and the duct brand. Trusted names such as Polyaire, Bradflo, and Safe-T-Flex carry clear certification, so you know the insulation performs as stated.
Duct Sizing & Lengths
Heating ducts come in a range of diameters, usually from 250mm up to 500mm, and they are sold in 6m lengths. The size and number of runs your home needs impacts the final price.
Here is how it works. A main trunk line leaves the heater at a larger diameter, often 350mm to 400mm. It then splits into smaller branch runs of 250mm to 300mm that feed each ceiling vent. A larger home has more rooms, longer runs, and more outlets, so it calls for more ducts and more labour.
Your heater capacity guides the sizing too. Gas ducted heaters range from around 15kW for a small home up to 35kW for a large one. A higher capacity heater moves more air, so it pairs with larger ducts and a greater number of outlets to spread the warmth evenly.
This is why two homes on the same street can receive different quotes. A compact three bedroom home might use six to eight outlets on modest runs. A larger family home might use twelve or more outlets across long runs, which increases both the materials and the install time.
Heater Brand Doesn’t Impact Ducting, But Sizing Does
A common question is whether brands such as Brivis, Braemar, or Bonaire each need their own special ducting. Flexible duct fits across all major heater brands. The duct itself comes from dedicated duct manufacturers rather than the heater maker.
What your heater brand and model do shape is the sizing. Each unit has a rated output in kilowatts and a recommended airflow. Your installer matches the trunk and branch sizes, the number of outlets, and the return air setup to that output. A premium high output unit guides larger ducts and more outlets, while a compact unit has a leaner layout.
So the brand on your heater influences the design of the duct system, even though the duct components themselves work happily with any of them. When you replace your ducts, the installer reviews your current heater and tailors the new ductwork to suit it.
Signs Your Heating Ducts Might Need Replacing
Many Melbourne homes run on ducts fitted during the housing boom of the 1990s and 2000s. After 15 to 20 years, the materials reach the end of their best life. Here are the signs that duct replacement may be better than duct repair:
- Cold rooms or uneven warmth. When one end of the house stays chilly while another feels toasty, a sagging or disconnected run is often the cause.
- Rising heating bills. Worn ducts let warm air escape into the roof before it reaches you, so the heater runs longer to keep up.
- Visible damage. Cracks, torn insulation, crushed sections, or joints that have pulled apart all point to ducts past their prime.
- Mould in flexible duct. The porous insulation holds spores, so replacement is the clean, lasting fix.
- Pest damage. Rodents and possums can chew through runs and leave contamination, which makes a fresh duct system the healthiest choice.
- Asbestos in older homes. Homes built before 1990 may carry asbestos in the original duct insulation. A licensed professional handles removal safely, followed by modern, safe ducting.
- A poorly designed original layout. Some homes carry comfort problems from day one because the ducts were undersized. A redesigned, balanced system solves this.
- A change of system. Moving from gas heating to reverse cycle air conditioning usually calls for ductwork sized to the new unit.
A duct replacement turns these everyday frustrations into a warm, even, efficient home. Many homeowners notice the difference on the very first cold evening after the work is done.
How Gas Heating Ducts Differ from Air Conditioning
If a reverse cycle changeover is on your mind, this is a useful point to understand. Heating ductwork and air conditioning ductwork come from the same family of product, yet they are specified for different jobs. A few elements set them apart.
Insulation rating. In Melbourne, heating ducts run on a baseline of R1.0. Once a duct carries cooling as well, the standard is R1.5. Cooling pushes air well below room temperature, so the extra insulation is important.
Condensation control. A cooling duct turns cold on the outside. When warm, humid air meets that cool surface, moisture can form. A sound foil outer jacket and the higher R rating keep the duct dry and the roof space healthy. A heating duct runs warm, so its surface sits above the surrounding air and stays dry with ease.
Airflow and sizing. Cooling usually moves more air than heating to deliver the same comfort. So a reverse cycle system often calls for larger ducts and more outlets than a gas heater of a similar rating. This is why you usually can’t use heating ducts for air conditioning.
Where the ducts run. Many older Melbourne gas systems run underfloor with floor vents, which suits heating beautifully because warm air rises. Cooling works the other way, since cool air falls. That makes ceiling outlets and roof space ducting the natural home for a reverse cycle system. If that isn’t possible, you can get floor consoles for air conditioning.
VEU Rebates Don’t Apply for Ductwork Upgrades Only
The discount rewards the full switch from gas to an efficient reverse cycle system. Many Melbourne homeowners pair a duct upgrade with a switch to a ducted reverse cycle system. One system then heats your home in winter and cools it in summer.
This is where the Victorian Energy Upgrades program helps. Eligible households can receive up to $5,530 off when they replace a ducted gas heater with an efficient ducted reverse cycle air conditioner. The Victorian Government reports energy bill savings of up to $1,140 a year from the same change. We provide the discount upfront, so you enjoy a lower price from day one.
A reverse cycle changeover from gas heating usually requires new ductwork, with the exception of the Braemar Dominator Series 2.
How to Get an Accurate Price For Your Home
The ranges above give you a solid starting budget. Your real figure depends on your home, and the clearest way to find it is a quick onsite assessment. An installer will:
- Measure your duct runs and count your outlets.
- Check the roof space or subfloor for access and condition.
- Review your heater capacity and recommend the right duct size and R rating.
- Give you a written quote with the parts, the labour, and the timeline laid out clearly.
With that detail in hand, you can compare quotes with confidence and choose the option that suits your home and your budget.
