Hot water rebates and running costs in South Australia
The dearest electricity in Australia and the cleanest mainland grid.
What a hot water system costs to run in South Australia, what you can claim towards replacing it, and the local facts that change the answer here — the tariff structure, the climate and the grid.
What you can claim in South Australia
Federal Small-scale Technology Certificates
$800–$1,200 off an eligible heat pump or solar thermal system
Available in every state. The installer claims the certificates and discounts your quote, so there is nothing for you to lodge. South Australia sits in STC Zone 3. Gas and electric resistance systems create no certificates.
Administered by the Clean Energy Regulator. Official scheme page. Last verified 5 September 2026.
Retailer Energy Productivity Scheme (REPS)
Roughly $300–$600 through a participating energy retailer
- Delivered through participating retailers rather than claimed from government.
- The amount varies by retailer and by the system installed.
Administered by Government of South Australia. Official scheme page. Last verified 5 September 2026.
Why South Australia is different
South Australia pulls in two directions at once. Its electricity is the most expensive in the country at 41.9c per kilowatt hour — 52% above Victoria — which makes every electric option look worse on running cost. Its grid is also the cleanest on the mainland at 0.22 kg CO₂-equivalent per kilowatt hour, roughly a third of Victoria's, which makes every electric option look far better on emissions.
The result is the only mainland state where a heat pump loses to gas instantaneous on running cost. On our figures a heat pump costs about $524 a year in Adelaide against $474 for gas instantaneous, for a household that also cooks with gas — and it stays behind over ten years too, because it costs about twice as much to install.
That flips if hot water is the only thing you use gas for. Then the whole daily supply charge is part of what hot water costs you, gas instantaneous rises to about $650 a year, and the heat pump wins on both running cost and the ten-year total. Whether you also cook or heat with gas is genuinely the deciding question in South Australia, which is why the calculator asks it.
On emissions there is no ambiguity. South Australia is the one mainland state where a heat pump comfortably beats gas — 249 kg of CO₂-equivalent a year against 476 — because the grid it draws on is so much cleaner than the national average.
The Retailer Energy Productivity Scheme is delivered through participating energy retailers rather than claimed from government, and is typically worth $300 to $600 depending on the retailer and the system. Because it comes through the retailer, it is worth asking more than one.
Every system at South Australia prices
A three-person household using 120 litres of hot water a day, at South Australia's reference rates and the Adelaide climate. On these assumptions the cheapest system to run in South Australia is solar thermal with gas boost at about $348 a year.
| System | Cost per year | Rebates | 10-year total | CO₂e a year |
|---|---|---|---|---|
| Solar thermal with gas boost | $348 | −$1,100 | $8,880 | 161 kg |
| Gas instantaneous | $474 | — | $7,094 | 476 kg |
| Heat pump | $524 | −$1,100 | $8,792 | 249 kg |
| Gas storage | $582 | — | $8,222 | 688 kg |
| Solar thermal with electric boost | $642 | −$1,100 | $11,818 | 305 kg |
| LPG instantaneous | $716 | — | $9,511 | 558 kg |
| LPG storage | $1,026 | — | $12,660 | 809 kg |
| Electric storage | $1,187 | — | $13,773 | 623 kg |
A three-person household in South Australia using 120 litres of hot water a day, at 41.9c/kWh and 3.05c/MJ for gas, with the Adelaide climate and the South Australia grid's emissions factor of 0.22 kg CO₂e per kWh. Change any of it in the calculator.
Your own household will differ. Put your bill figures into the calculator and every number above recalculates.
The certificate value is falling every January
The federal scheme is winding down on a fixed schedule. Certificates are deemed over a period that shortens by one year every 1 January, and the scheme ends in 2030 — so the same system installed in South Australia in December earns about a fifth more than it would a few weeks later.
| Install year | Deeming period | Indicative value |
|---|---|---|
| 2025 | 6 years | — |
| 2026 (now) | 5 years | $800–$1,200 |
| 2027 | 4 years | $640–$960 |
| 2028 | 3 years | $480–$720 |
| 2029 | 2 years | $320–$480 |
| 2030 | 1 years | $160–$240 |
The certificates a heat pump creates are deemed over a period that shortens by one year every 1 January until the scheme ends in 2030. Waiting from December to January costs about a fifth of the discount, for exactly the same system. It is the one piece of timing advice on this site that is worth acting on.
How South Australia compares
Victoria's grid is the dirtiest in the country — the clearest possible contrast with South Australia's, which is the cleanest on the mainland. New South Wales runs a comparable-sized incentive through a fixed scheme rather than retailers, which is the more usual way state programs work.
Frequently asked questions
What's the cheapest hot water system to run in Adelaide?
Solar thermal with a gas boost, at roughly $348 a year for a three-person household on 120 litres a day. It carries the highest install cost of the options here too, so the ten-year column is worth a look before deciding.
How much is South Australia's heat pump rebate worth?
$1,100 to $1,800 in total, combining the federal certificates with the Retailer Energy Productivity Scheme (REPS) — REPS specifically is delivered through your energy retailer rather than government, so the number varies by who you ask and is worth comparing across more than one.
What does electricity cost for hot water in South Australia?
The reference rate is 41.9c per kilowatt hour with a daily supply charge of $1.80, from the AER's 2026–27 Default Market Offer (DMO 8) effective 1 July 2026. A controlled-load circuit for hot water is available at 22.2c. Retailer offers often beat this reference rate, so use your actual bill in the calculator.
Does a heat pump make sense in Adelaide's climate?
Yes, and more so than the running-cost figures alone suggest — an effective coefficient of performance around 2.29 against a 3.2 nameplate, close to the national middle, on a grid that is also the cleanest on the mainland. It still uses under half the electricity a resistance element would.