Worked Estimates and Checklists
Going all-electric: a worked example of replacing gas heating, hot water and cooking
An illustrative whole-home gas-to-electric budget for an Australian house, covering reverse cycle heating, heat pump hot water, induction cooking, gas disconnection and the yearly saving.
Replacing every gas appliance at once costs more upfront than swapping one, but it is the only way to stop paying the daily gas supply charge, which is often the deciding number. In the illustrative example below, a three-bedroom house replaces ducted gas heating, gas storage hot water and a gas cooktop. The gross budget is about $20,850; after illustrative incentives about $18,050; and the yearly energy saving, including the gas supply charge, is about $1,580, before any gas disconnection or abolishment fee. Whether this makes sense for you depends on the age of your gas appliances, your tariffs and the incentives you qualify for. This guide is part of the heating and cooling quote checklist.
All prices, tariffs and savings are illustrative examples to show the method.
The house and its current gas use
- Three-bedroom single-storey house, ceiling insulation in reasonable condition.
- Ducted gas heater, about 15 years old.
- Gas storage water heater, 10 years old.
- Gas cooktop.
- Illustrative gas use: 40,000 MJ a year for heating, 15,000 MJ for hot water, 2,000 MJ for cooking.
- Illustrative gas tariff: 4 c/MJ usage plus $1.00 a day supply.
Current yearly gas cost: 57,000 MJ × $0.04 = $2,280, plus 365 × $1.00 = $365 → $2,645.
The replacement plan
| Item | Replacement | Illustrative price |
|---|---|---|
| Heating | Ducted reverse cycle, 14 kW, re-using sound ductwork after inspection | $11,500 |
| Remove old gas ducted heater, cap gas line | Licensed gasfitter | $600 |
| Hot water | 270 L heat pump | $4,200 |
| Cooking | Induction cooktop (supply and install) | $1,800 |
| Electrical | Switchboard upgrade and new circuits | $2,000 |
| Gas meter | Disconnection or abolishment (see below) | $750 |
| Gross total | $20,850 |
The ducted price sits within the installation cost estimator's illustrative range for re-using ductwork (14 kW × $500–$850 + $1,500 = $8,500–$13,400). The switchboard line is explained in switchboard and circuit costs.
Incentives (illustrative)
| Incentive | Applies to | Illustrative amount |
|---|---|---|
| STCs | Heat pump water heater | −$800 |
| State discount for hot water (e.g. VEU or NSW ESS) | Heat pump water heater | −$600 |
| State discount for space heating (where offered) | Reverse cycle | −$900 |
| State hot water rebate (e.g. Solar Victoria, if eligible) | Heat pump water heater | −$500 |
| Total incentives | −$2,800 |
Net cost: $20,850 − $2,800 = $18,050.
Incentive availability, amounts and stacking rules depend on your state, property and the products chosen. See the guides to STCs, Victorian rebates and the NSW scheme.
The new running cost
Converting the gas use to useful heat and then to electricity, using the method in the running-cost guide:
| Use | Gas MJ | Useful energy | Electric system | Electricity kWh | Cost (illustrative tariff) |
|---|---|---|---|---|---|
| Heating | 40,000 at 80% | 32,000 MJ = 8,889 kWh | Ducted reverse cycle, effective COP 3.5 incl. duct losses | 2,540 | 2,540 × $0.32 = $813 |
| Hot water | 15,000 at 70% | 10,500 MJ = 2,917 kWh | Heat pump COP 3.5 | 833 | 833 × $0.20 = $167 |
| Cooking | 2,000 at about 40% | 800 MJ = 222 kWh | Induction at about 85% | 261 | 261 × $0.32 = $84 |
| Total | 3,634 | $1,064 |
Yearly saving: $2,645 (old gas bill) − $1,064 = about $1,581. The electricity supply charge does not change because you already pay it.
Simple payback and financing
- Net cost $18,050 ÷ $1,581 a year ≈ 11.4 years, before energy price changes.
- If prices rise 3% a year, payback shortens to roughly 10 years.
- If the gas ducted heater still had years of life left, part of the cost is replacing equipment early; if it was about to fail, compare against the cost of a new gas heater instead.
Comparing with like-for-like replacement. If the old ducted heater and hot water would need replacing anyway (say an illustrative $9,000 for new gas equivalents), the extra cost of going electric is $18,050 − $9,000 = $9,050, and the payback on that extra is about 5.7 years.
If you borrow, use the upgrade loan calculator and read the Home Energy Upgrades Fund guide. Borrowing $18,050 over 7 years at an illustrative 7% p.a. would cost about $272 a month — more than the monthly energy saving of about $132, so the loan only pays off over its life if the system outlasts it by several years.
Disconnection, abolishment and timing
Once the last gas appliance is capped, ask your retailer to close the account. You will be offered a disconnection (meter left in place) or abolishment (meter and service removed permanently). The fee is set by the gas distributor and can differ a lot between the two and between networks; the $750 above is purely illustrative (on the Victorian networks the AER-approved abolishment charge for 2023–28 is about $250, while networks with cost-reflective charges can be much higher). Ask for the current fee and what charges apply until the work is done, in writing. In Victoria, read the gas rules guide for the end-of-life hot water rule from 1 March 2027.
Order of work that tends to avoid problems:
- Electrical assessment and switchboard upgrade.
- Heating and hot water installation.
- Cooktop.
- Gasfitter caps all appliances.
- Retailer arranges disconnection or abolishment; final gas bill.
Frequently asked questions
Can I switch in stages?
Yes. Many households replace each gas appliance as it fails. You keep paying the gas supply charge until the last one goes, so stage the most expensive-to-run appliances first.
Will my electricity bill go up?
Yes, but by less than the gas bill falls in most cases. The example shows electricity use rising by about 3,600 kWh while the gas bill disappears.
Is induction cooking necessary?
Not for heating and hot water savings, but you cannot close the gas account while a gas cooktop remains.
Does rooftop solar help?
Yes, especially for hot water and daytime heating or cooling. Running loads during solar hours reduces grid purchases.
Official sources
- energy.gov.au — household electrification guidance
- Victorian Government energy website — gas substitution and electrification
- Energy Made Easy — compare offers after switching
- Energy and Water Ombudsman NSW and Energy and Water Ombudsman Victoria — disputes with retailers about disconnection and fees
