Ducted Gas Heating Costs: What You Can Expect to Pay (A Real Answer, Not a Runaround)
You have probably searched this question, clicked three websites, and still have no idea what you are actually going to pay. That is because most answers online are written to rank on Google, not to help you. This one is different. We are going to walk you through the real costs of ducted gas heating in Australia, what drives those costs up or down, what it actually costs to run per hour, and whether it is worth it for your home. No fluff. No bait and switch.
What Does a New Ducted Gas Heating System Cost to Install?
Let us start with the number most people are after. A fully installed ducted gas heating system in an average Australian home typically costs between $3,500 and $9,000, with most homeowners landing somewhere in the $4,500 to $7,000 range. That is a wide range, and for good reason. The price depends on the size of the unit, the size and layout of your home, how much ductwork is needed, and who installs it. Here is a rough breakdown to give you a clearer picture:Small Home
$3,500 – $5,000
Up to 3 bedrooms, minimal ductwork, existing gas connection
Medium Home
$5,000 – $7,000
4–5 bedrooms, standard duct layout, new installation
Large Home
$7,000 – $9,000+
6+ rooms, zoning, complex duct runs or two-storey layout
These figures are for supply and installation in the Sydney and surrounding regions. Prices vary by location, brand, and complexity. The only way to get an accurate number for your home is a site assessment — not a quote over the phone.
What Affects the Price?
If you have had two quotes that are $2,000 apart, this section explains why. The price of a ducted gas heating system is not just about the unit itself. Here is what actually moves the number:| Factor | Impact on Cost | What to Know |
|---|---|---|
| Unit size (kW output) | High | Bigger home needs a more powerful unit. Undersizing is a false economy — your system will run constantly trying to keep up. |
| Brand and model | Medium-High | Brands like Braemar, Brivis, and Ducted Airflex vary in price and efficiency rating. Higher star rating = lower running costs long term. |
| Amount of ductwork | High | More rooms, longer runs, and awkward roof cavities all add to labour and materials. A two-storey home costs more than a single-level. |
| Zoning system | Medium | Zoning lets you heat specific rooms only. Adds $500–$1,500 but can significantly reduce your running costs over time. |
| Existing gas connection | Medium | If your home already has a gas line, great. If not, connecting to mains gas adds cost and requires a licensed gas fitter. |
| Access and installation complexity | Variable | Tight roof cavities, unusual home layouts, and older homes with no prior ductwork all affect labour time and cost. |
Worth Knowing
Always ask your installer if zoning is available for your layout. Heating only the rooms you are using can cut your gas bill significantly over a winter. The upfront cost usually pays for itself within a few seasons.
How Much Does Ducted Gas Heating Cost to Run Per Hour?
This is the question that really matters for most homeowners. You can stomach a big upfront cost if the ongoing bills are manageable. So here is the real number. A ducted gas heating system typically costs between $0.20 and $0.60 per hour to run, depending on the size of the unit, your home's insulation, the outside temperature, and current gas prices in your area. For context, a standard 5-star rated 18kW unit running in a well-insulated 4-bedroom home might cost around $0.30–$0.40 per hour in moderate winter conditions.Per Hour (Typical)
$0.25 – $0.45
Moderate winter conditions, average-sized home
Per Day (8 hrs)
$2 – $4
Assuming 8 hours of use on a cold day
Per Season (Est.)
$300 – $700
Full winter usage, average home, no zoning
Running Cost Reality Check
If your ducted gas heating system is more than 10 years old, it is almost certainly running at a much lower efficiency than when it was installed. An ageing unit can cost significantly more per hour to run. A service check or replacement assessment can quickly tell you whether you are wasting money every time you switch it on.
Replacing an Old Ducted Heating Unit: What to Expect
If your existing system has packed it in or is simply underperforming, a ducted heating unit replacement is often more cost-effective than you think, because the ductwork is already in place. You are essentially just swapping the unit itself. A straight unit replacement (same brand, similar size, existing ducts in good condition) typically costs between $2,000 and $4,500 depending on the unit spec. If the existing ductwork needs repair or partial replacement, add $500–$1,500 on top.- Unit only replacement (ductwork reused): $2,000 to $4,500 supply and install
- Unit plus duct repairs or partial re-run: $3,000 to $6,000 depending on extent
- Full system replacement (unit and all new ductwork): $5,000 to $9,000+
If your system is between 12 and 15 years old and starting to need regular repairs, a replacement is almost always the better financial decision. You stop spending on repairs and start saving on running costs at the same time.
What Does a Ducted Gas Heating Service Cost?
A professional ducted gas heating service typically costs between $150 and $300 in the Sydney region, depending on the complexity of the system and whether any parts or repairs are required during the service visit. Here is what a standard annual service covers:- Cleaning and inspecting the burner assembly
- Checking the heat exchanger for cracks or corrosion (a cracked heat exchanger is a carbon monoxide risk — not something to skip)
- Inspecting and cleaning the flue system
- Checking gas pressure and combustion settings
- Inspecting ductwork connections and grilles for leaks
- Testing the thermostat and controls
- Filter check and clean (if accessible)
How Often Should You Service It?
Annually is the industry recommendation for ducted gas heating, and it is not just to keep your system running efficiently. Gas appliances carry a safety obligation. A cracked heat exchanger can leak carbon monoxide into your home with no warning. An annual service is cheap insurance against something far more serious.
Is Ducted Gas Heating Expensive to Run? The Honest Answer
The short answer: not necessarily, but it depends on your setup. Gas ducted heating gets a bad reputation for running costs, and some of it is earned, but most of the complaints come from systems that are:- Old and inefficient (pre-5-star rating era)
- Incorrectly sized for the home
- Running without zoning (heating the whole house when only one room is occupied)
- Operating through leaky or damaged ductwork
- Not serviced regularly, causing the burner to work harder than it should
Advantages of Ducted Gas Heating
- Heats a whole home quickly and evenly
- Not affected by cold outdoor temperatures (unlike reverse-cycle heat pumps in very cold climates)
- Generally lower upfront cost than ducted reverse-cycle
- Gas prices are relatively stable compared to electricity in many areas
- Zoning options allow efficient room-by-room control
- Comfortable, dry warmth preferred by many households
Considerations to Be Aware Of
- Requires an existing gas connection or cost of new connection
- Older units can have poor energy star ratings
- Does not provide cooling — you need a separate system for summer
- Annual servicing is a must, not optional
- Running costs increase significantly if the system is poorly maintained
- Gas prices can vary by region and season
Not Sure If Gas Heating Is Right for Your Home?
We can walk you through your options based on your home's layout, your existing setup, and what will actually give you the best result for your budget. No sales pressure. Just a straight conversation. Book a free assessment here.Frequently Asked Questions
How much does ducted gas heating cost to install in Sydney?
In the Sydney region, a fully installed ducted gas heating system typically costs between $3,500 and $9,000 depending on the size of the home, the unit selected, and how much ductwork is involved. Most average-sized homes fall in the $4,500 to $7,000 range. The only accurate way to know what your installation will cost is a site visit and assessment.
How much does ducted heating cost to run per hour?
A typical ducted gas heating system costs between $0.25 and $0.45 per hour to run in moderate conditions. On a very cold day with a large home and no zoning, you could be closer to $0.60 per hour. A modern, well-maintained system with zoning in a well-insulated home sits at the lower end of that range.
How much does a ducted heating unit replacement cost?
If the existing ductwork is in good condition, a straight unit replacement typically costs between $2,000 and $4,500 for supply and installation. If the ducts need partial repair or replacement, budget $3,000 to $6,000. A full system replacement including all new ductwork can reach $9,000 or more for larger homes.
Is ducted gas heating expensive to run compared to reverse-cycle?
Not necessarily. A modern ducted gas heating system is cost-competitive with reverse-cycle electric heating for most Australian homes, particularly in colder climates where heat pumps work less efficiently. The biggest factors are the age and star rating of the unit, whether you have zoning, and how well the ductwork is sealed. An old, unzoned gas system will be expensive to run. A new, zoned system generally will not be.
How much does a gas ducted heating service cost?
A standard annual gas ducted heating service in Sydney typically costs between $150 and $300. The service covers burner cleaning, heat exchanger inspection, flue check, gas pressure testing, duct inspection, and controls testing. If any parts need replacing, those are quoted separately. Annual servicing is strongly recommended for both performance and safety reasons.
Can I get a ducted gas heating quote without a site visit?
You can get a rough ballpark over the phone, but an accurate quote requires a technician to assess your home in person. The layout of your home, roof cavity access, existing gas connection, and duct requirements all affect the final price significantly. Any installer quoting you a firm price without seeing your home is guessing, and you could end up with a surprise bill on installation day.
