Ducted Gas Heating Australia: Costs, Running Costs & Pros and Cons

On a frosty July morning in Melbourne or Canberra, there's not much that beats walking into a house that's already warm in every room. That's the big appeal of ducted gas heating. One central heater, warm air flowing quietly through vents in the floor or ceiling, and no little heaters to drag from room to room.

But gas prices have climbed, the rules around gas are changing, and reverse cycle air con keeps getting better. So is ducted gas still a smart choice in 2026? This guide covers how it works, what it costs to install and run, the honest pros and cons, and how to keep yours safe and efficient.

How does ducted gas heating work?

A ducted gas heating system has three main parts:

• The heater unit. Usually sits outside, under the floor or in the roof space. It burns natural gas or LPG to heat air.
• The ducts. Insulated flexible tubes that carry the warm air to each room.
• The vents and thermostat. Warm air comes out through floor or ceiling vents, and a wall thermostat tells the system when to switch on and off.

The heater pulls in cooler air from inside the house through a large return-air grille, warms it up over a heat exchanger, then a fan pushes it back out through the ducts. The flame and the air you breathe never mix, and the combustion fumes are vented safely outside through a flue.

How much does ducted gas heating cost to install?

For a new system in an average Australian home, expect to pay somewhere between $3,000 and $10,000 supplied and installed. Where you land in that range depends on:

• The size of your home. More rooms means a bigger unit and more ducting.
• Access. Single-storey homes with a roof or subfloor that's easy to get into cost less than double-storey homes.
• Zoning. Being able to heat only the living area or only the bedrooms adds cost upfront but saves money every winter.
• Efficiency. Higher star-rated units cost more to buy and less to run.
• Existing gas. If your home isn't connected to mains gas, the connection can add a lot to the bill.

Swapping an old unit for a new one on existing, good-condition ducts is usually much cheaper than a full new install. Old ducts are worth checking, though. Torn or poorly insulated ducting can leak a surprising amount of heat into the roof.

What does ducted gas heating cost to run?

This is the question that matters most, and the honest answer is: it depends on your heater, your house and your gas rate. Still, some rough numbers help.

Using Sustainability Victoria's figures, a small 100m² home with an unzoned 3-star system costs around $1,960 a year to heat. The same home with a 6-star system drops to around $1,540. Larger homes that run the heating for long winter hours can easily go past $3,000 a year.

Work out your own running cost per hour

You can get a quick estimate with two numbers:

1. Your heater's gas input in megajoules per hour (MJ/h). It's on the unit's data plate or in the manual. Many home systems sit somewhere around 60 to 100 MJ/h.
2. Your gas usage rate in cents per MJ, found on your gas bill.

Multiply them together. For example, an 80 MJ/h heater on a gas rate of 4c per MJ costs about $3.20 an hour when it's running flat out. In real life, it'll cost less than that because the burner cycles down once the house reaches your set temperature.

Quick tip: Your thermostat setting has a big effect on cost. Every degree higher can add roughly 10 to 15% to your heating bill. Around 18 to 20°C is comfortable for most people in winter.

Ducted gas heating vs reverse cycle: which is cheaper?

Here's where things have shifted over the past few years. Modern reverse cycle air conditioners are heat pumps. Instead of burning fuel, they move heat from the outside air into your home, and they can produce three to five units of heat for every unit of electricity they use. That efficiency means a good reverse cycle system is now often cheaper to run than gas, especially if you have rooftop solar.

	Ducted gas	Ducted reverse cycle
Heating	Yes, fast and very warm	Yes
Cooling	No (unless you add a separate system)	Yes, same system
Running cost	Moderate to high, depends on gas price	Often lower, especially with solar
Works with solar panels	No	Yes
Very cold climates	Excellent	Good, choose a model rated for cold weather
Gas supply charge	Yes, a daily fee on your gas bill	No, if you go all-electric

That last point catches people out. Even if you barely use gas, you pay a daily supply charge just to stay connected. If heating is your only gas appliance, switching away can remove that fee altogether.

The pros and cons of ducted gas heating

Why people love it

• Warm, even heat throughout the whole house
• Heats up quickly, even on the coldest mornings
• Quiet, with no units on the walls inside
• Hidden ducts and vents, so it doesn't spoil the look of a room
• Works well in cold climates like Victoria, Tasmania and the ACT

The downsides

• Heating only, so you'll need a separate system for summer cooling
• Running costs are tied to gas prices, which have risen
• Can't take advantage of your rooftop solar
• Floor vents can blow dust around and need regular cleaning
• Needs regular safety servicing

Is ducted gas heating still worth it in 2026?

It can be, in the right situation. Ducted gas still makes sense if:

• You already have a ducted gas system with good ducts and just need a replacement unit
• You live somewhere very cold and want strong, fast heat
• You use gas for cooking and hot water too, so you're paying the supply charge anyway

It's worth looking hard at reverse cycle instead if:

• You're installing heating from scratch
• You want cooling in summer as well
• You have, or plan to get, solar panels
• You'd like to get off gas completely

Rules are also changing. Victoria, for example, has already moved new homes towards all-electric, and several states offer rebates for swapping gas heaters for efficient electric ones. Before you buy, check what applies where you live through your state government's energy website.

How to cut the running costs of ducted gas heating

1. Use zoning. Heat the living areas in the evening and the bedrooms only before bed. This alone can make a big difference.
2. Set a sensible temperature. 18 to 20°C, not 24°C.
3. Use the timer. Have the heating switch on 20 minutes before you get up, rather than leaving it running overnight.
4. Close doors to unused rooms and shut the vents in those rooms if your system allows it.
5. Seal draughts around doors and windows. Warm air escaping is money escaping.
6. Check your insulation and ducts. Good ceiling insulation and well-sealed ducts keep the heat where you want it.
7. Keep the filter and return-air grille clean so the system doesn't have to work harder than it should.

Safety and servicing: don't skip this

Any gas heater burns fuel, and a faulty one can leak carbon monoxide, a gas you can't see or smell. That's why regular servicing matters.

• Have your heater serviced by a licensed gasfitter at least every two years, or as the manufacturer recommends.
• Ask them to test for carbon monoxide spillage as part of the service.
• If you rent, check with your landlord about when the last gas safety check was done. In some states, such as Victoria, regular checks are part of rental requirements.
• Consider installing a carbon monoxide alarm near living and sleeping areas.

Warning signs that your heater needs attention straight away include a yellow or orange flame instead of blue, soot or staining near the heater, a strange smell, or headaches and nausea that ease when you leave the house. If you notice any of these, turn the heater off, open windows and call a licensed gasfitter. Never try to repair a gas appliance yourself.

How long does a ducted gas heater last?

With regular servicing, many ducted gas heaters last around 15 to 20 years. If yours is getting close to that age, is noisy, struggles to heat the house or needs frequent repairs, it's worth getting quotes on both a new gas unit and a reverse cycle system so you can compare properly.

Frequently asked questions

Is ducted gas heating expensive to run?

It can be. A small, efficient system might cost around $1,500 a year to run, while a large home with an older unit can pass $3,000. Zoning, sensible thermostat settings and good insulation all help bring that down.

Can I zone an existing ducted gas system?

Often, yes. A heating technician can usually add motorised zone dampers to the existing ducts so you can heat different areas separately.

Is ducted gas cheaper than reverse cycle air con?

Not always. Modern reverse cycle systems are very efficient and are often cheaper to run, especially in homes with solar. Ducted gas can still compete in very cold areas or where gas is already used for other appliances.

How often should ducted gas heating be serviced?

At least every two years by a licensed gasfitter, including a carbon monoxide test. Clean the filter and return-air grille more often, ideally at the start of each winter.

The bottom line

Ducted gas heating still delivers some of the most comfortable whole-home warmth you can get, and if you already have a decent system, replacing the unit can make a lot of sense. But if you're starting from scratch, want cooling too, or have solar on the roof, a ducted reverse cycle system deserves a serious look.

Whatever you choose, get a few quotes, ask about star ratings and zoning, and keep up with the safety servicing. A warm house is great. A warm, safe house that doesn't blow out your winter bill is even better.

Costs and running figures are general estimates as of October 2026 and will vary with your home, climate and energy prices. Always get quotes from licensed installers and check current rules and rebates in your state. See our disclaimer for more.