For decades across Melbourne, Canberra, and regional New South Wales, central gas ducted heating was the undisputed king of winter comfort. Plumbers connected 80 to 120 Megajoule (MJ/hr) units to roof spaces or subfloors, and families enjoyed instant, scorching airflow on frosty mornings.
That financial reality has turned upside down. Sharp spikes in wholesale gas export parity pricing, compounding pipeline network distribution tariffs, and dramatic efficiency breakthroughs in DC inverter reverse cycle heat pumps have completely rewritten Australian home heating economics.
Today, burning natural gas to heat an Australian home is frequently two to three times more expensive per hour than warming that exact same floor plan with an energy-efficient reverse cycle split system or ducted heat pump.
Is Gas Heating Cheaper Than Electric in Australia?
No, gas heating is no longer cheaper than reverse cycle electric heating in Australia. A modern reverse cycle heat pump produces 3.5 to 5.0 units of thermal heat for every 1 unit of electricity consumed, delivering heat at 6¢ to 9¢ per thermal kWh, compared to 14¢ to 18¢ per thermal kWh for standard 4-star gas ducted heating.
The economics shift even further in favor of electric heat pumps when you examine real-world billing realities across typical Australian homes:
- Seasonal Dollar Savings: An average 3-bedroom Victorian or ACT home saves between $600 and $1,100 per winter season simply by running an electric reverse cycle system instead of central gas ducted heating.
- Hourly Running Cost Gap: Running an 85 MJ gas ducted heater costs between $2.10 and $2.85 per hour at average Australian gas rates, whereas an equivalent 12.5 kW ducted inverter heat pump costs between $0.85 and $1.35 per hour to run.
- The Rooftop Solar Multiplier: Australia has the highest per-capita rooftop solar uptake on earth. Running a reverse cycle system during sunny daytime hours offsets grid power entirely, generating free space heating that gas infrastructure can never replicate.
- Eliminating Daily Supply Charges: Households that decommission gas ducted heating, cooktops, and storage hot water can abolish their gas meter completely, pocketing an extra $300 to $420 each year in avoided connection supply fees.
Gas Ducted vs Reverse Cycle Comparison Matrix
Comparing space heating technologies requires looking past upfront unit prices and analyzing delivered thermal heat efficiency. A 6-star condensing gas heater uses cutting-edge engineering, but physical combustion limits its maximum thermal delivery to around 91% of fuel input.
In contrast, reverse cycle heat pumps do not create heat by burning fossil fuels. Instead, they use a refrigeration cycle to collect ambient warmth from outdoor air and compress it into the living space, regularly achieving 350% to 500% thermal efficiency under Australian Standard AS/NZS 3823.2.
| Heating System Type | Energy Source | Thermal Efficiency | Delivered Cost / kWh | Average Winter Bill | Summer Cooling? |
|---|---|---|---|---|---|
| 3-Star Gas Ducted Heating Older pilot-light / pilotless unit | Natural Gas (~80–95 MJ/hr) | 66% Thermal (AS 4556) | 16.8¢ / thermal kWh | $1,700 – $2,250 | No (Heating only) |
| 4-Star Gas Ducted Heating Standard electronic ignition | Natural Gas (~80–95 MJ/hr) | 77% Thermal (AS 4556) | 14.5¢ / thermal kWh | $1,450 – $1,850 | No (Heating only) |
| 6-Star Condensing Gas Ducted Secondary stainless heat exchanger | Natural Gas (~70–90 MJ/hr) | 91% Thermal (AS 4556) | 12.2¢ / thermal kWh | $1,200 – $1,550 | No (Requires add-on coil) |
| Standard Inverter Ducted Heat Pump Zoned central reverse cycle | Grid Electricity (COP 3.8) | 380% Heat Pump Efficiency | 7.5¢ / thermal kWh | $750 – $950 | Yes (Full Refrigerated AC) |
| High-Efficiency Multi-Split System Dedicated bedroom & living heads | Grid Electricity (COP 4.5) | 450% Heat Pump Efficiency | 6.3¢ / thermal kWh | $620 – $800 | Yes (Individual Room Zoning) |
| Solar-Offset Reverse Cycle Heat Pump Inverter ducted with 30% solar offset | Rooftop Solar + Grid (COP 3.8) | 490% Effective Efficiency | 5.1¢ / thermal kWh | $480 – $660 | Yes (Powered by Summer Solar) |
If you are sizing a ducted system from scratch or calculating room thermal losses, verify your home's total peak heating kilowatt requirement with our Residential Heat Load Calculator before finalizing equipment quotes.
How to Calculate Heating Costs: Megajoules vs Kilowatt-Hours
The primary reason Australian homeowners struggle to compare gas and electric heating costs is that utility providers bill them using completely different units of measurement: gas in Megajoules (MJ) and electricity in Kilowatt-hours (kWh).
To level the playing field, fridgies and building services engineers convert both fuels to delivered thermal heat energy. The critical conversion constant is: 1 kWh = 3.6 MJ.
The Gas Ducted Heating Cost Formula
Gas heaters lose heat up the flue. To calculate the effective cost per kilowatt-hour of thermal heat delivered into your living room:
Delivered Gas Cost ($/kWh) = (Gas Tariff in $/MJ × 3.6) ÷ Thermal Efficiency Percentage
Example: At a Victorian gas tariff of 3.1¢/MJ ($0.031/MJ) and an average 4-star heater efficiency of 77% (0.77):
($0.031 × 3.6) ÷ 0.77 = $0.1449 per thermal kWh (14.5¢/kWh).
The Reverse Cycle Heat Pump Cost Formula
Because reverse cycle heat pumps transfer outdoor heat rather than combusting energy, their thermal output is multiplied by their Coefficient of Performance (COP):
Delivered Electric Cost ($/kWh) = Electricity Tariff in $/kWh ÷ System COP Rating
Example: At a Victorian electricity tariff of 28.5¢/kWh ($0.285/kWh) and an inverter COP rating of 3.8:
$0.285 ÷ 3.8 = $0.075 per thermal kWh (7.5¢/kWh).
Notice that while raw grid electricity looks much more expensive on paper than raw gas (28.5¢ per kWh versus 3.1¢ per Megajoule), the heat pump's 3.8× energy multiplier cuts the delivered heating price in half. For standalone split system cooling calculations, compare hourly summer rates on our AC Running Cost Calculator.
Heating Running Costs Across Australian States
Heating running costs vary widely across Australia depending on local climate severity, winter heating degree days, and retail electricity versus gas supply pricing:
Victoria (VIC)
Victoria has Australia's highest domestic gas consumption, with Melbourne experiencing over 100 cold winter heating days per year. With Victorian retail gas hovering around 3.0¢ to 3.4¢/MJ and flat electricity tariffs averaging 28.5¢/kWh, switching a standard 160m² home from 4-star gas ducted heating to a 3.8 COP reverse cycle ducted system saves roughly $750 to $950 per winter. Adding rooftop solar into the mix pushes seasonal savings past $1,100.
New South Wales (NSW)
While Sydney's coastal fringe enjoys milder winters, Western Sydney and regional NSW (Orange, Bathurst, Southern Highlands) experience bitter overnight frosts. Domestic gas tariffs in NSW are among the highest in the country (averaging 4.0¢ to 4.5¢/MJ). Running gas ducted heating in Sydney or regional centers is particularly expensive, with reverse cycle heat pumps delivering 55% to 65% lower running costs across the heating season.
Australian Capital Territory (ACT) & Alpine Highlands
Canberra and alpine tablelands endure sub-zero winter temperatures, with severe frosts dropping ambient temperatures below -4°C. Older fixed-speed heat pumps struggled in these conditions, but modern low-ambient inverter heat pumps maintain their rated thermal output with automated coil defrost cycles. Because ACT winters are long and severe (120+ heating days), switching from expensive bottled LPG or natural gas ducted heaters delivers the highest dollar savings in Australia, frequently exceeding $1,200 to $1,500 per year.
South Australia (SA)
South Australia has the highest grid electricity prices in the country (averaging 42.5¢/kWh), but also leads the globe in residential rooftop solar installation rates. Homes with solar arrays that pre-warm living areas between 11:00 AM and 3:00 PM capture dramatic savings, bypassing both high evening power tariffs and expensive South Australian natural gas rates.
Trade Pros and Cons: Gas Ducted vs Heat Pumps
When fridgies and licensed gasfitters quote heating replacements on site, customer discussions involve more than just raw power bills. Both systems have real physical trade-offs:
| Heating Technology | Practical On-Site Advantages (Pros) | Practical On-Site Drawbacks (Cons) |
|---|---|---|
| Gas Ducted Heating |
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| Reverse Cycle Heat Pump |
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2026 Government Rebates and Electrification Incentives
Federal and state governments across Australia offer official decarbonisation incentives and energy efficiency rebates that substantially subsidise replacing residential gas heating with reverse cycle electric heat pumps:
- Victoria – Victorian Energy Upgrades (VEU) & Solar Victoria: Victorian households replacing a central gas ducted heater with an approved high-efficiency reverse cycle ducted system or multi-split heat pump can access $1,000 to $2,800 in direct discounts through accredited providers. Administered by the Essential Services Commission (ESC). Official program details: Victorian Energy Upgrades (energy.vic.gov.au) and Solar Victoria Heating & Cooling Rebates.
- New South Wales – Energy Savings Scheme (ESS) & PDRS: NSW residents can access Peak Demand Reduction Scheme (PDRS) and ESS Energy Savings Certificates when replacing older gas heating or low-efficiency systems with high-star inverter reverse cycle units, reducing supply and installation costs by $500 to $1,500. Administered by the NSW Government and IPART. Official program details: NSW Climate and Energy Action (energy.nsw.gov.au).
- Australian Capital Territory – Sustainable Household Scheme: Eligible Canberra homeowners can access zero-interest loans of up to $15,000 (repayable over up to 10 years) to finance reverse cycle heating upgrades, rooftop solar systems, and complete gas disconnection. Administered by the ACT Government. Official program details: ACT Climate Choices (climatechoices.act.gov.au).
- South Australia – Retailer Energy Productivity Scheme (REPS): South Australian households upgrading from gas heating to high-efficiency reverse cycle air conditioners can access discounts delivered through participating electricity and gas retailers. Administered by the Department for Energy and Mining and ESCOSA. Official program details: SA Energy & Mining REPS (energymining.sa.gov.au).
- Federal – Clean Energy Regulator (STCs): Air-source heat pump hot water units installed concurrently generate Small-scale Technology Certificates (STCs) under the Renewable Energy Target, cutting thousands off whole-home gas abolition projects. Official authority: Clean Energy Regulator (cleanenergyregulator.gov.au).
Before replacing an existing gas unit, inspect your current duct layout with a licensed refrigeration mechanic or check sizing specifications on our Gas Ducted Heating Size Calculator to ensure your ceiling registers can support modern airflow requirements. Building compliance and energy performance are governed by the National Construction Code (ABCB NCC) and Standards Australia (AS/NZS 3823 & AS/NZS 5141).