The Clean Energy Regulator’s STC factor falls from 6.8 certificates per kWh (May–December 2026) to 5.7 from 1 January 2027 and 5.2 from 1 July 2027.[1] At the $40 clearing house price, a 13.5 kWh battery earns about $3,672 now, about $3,078 in early 2027 and about $2,808 after July — roughly $864 less.[2]
That is the home battery rebate 2027 step-down, in dollars. The rest of this piece walks the chain in the order a buyer with a quote on the kitchen table actually asks it: what the cut costs at each common size, which date locks the rate, whether rushing December pays, whether a bigger battery earns more per kWh, whether state money stacks on top, and when the scheme stops entirely.
We have not installed or bench-tested any battery named here. This is an editorial synthesis of the regulator’s published factor schedule, manufacturer capacity figures and a named independent price index, checked on 16 September 2026.
What the cut costs on a 10 kWh, 13.5 kWh and 20 kWh battery
Every figure below values a certificate at $40 excluding GST, the fixed price of the STC clearing house.[2] That is the practical ceiling, not a guarantee. Open-market STC pricing fluctuates and is not regulated by the Clean Energy Regulator, so the amount an installer passes through to your invoice can sit below $40.[2]
| Usable capacity | May–Dec 2026 (6.8/kWh) | 1 Jan–30 Jun 2027 (5.7/kWh) | 1 Jul–31 Dec 2027 (5.2/kWh) | Lost across 2027 |
|---|---|---|---|---|
| 10 kWh | 68 certificates, about $2,720 | 57, about $2,280 | 52, about $2,080 | about $640 |
| 13.5 kWh | 91.8 certificates, about $3,672 | 76.95, about $3,078 | 70.2, about $2,808 | about $864 |
| 20 kWh (14 kWh full rate + 6 kWh at 60%) | 119.68 certificates, about $4,787 | 100.32, about $4,013 | 91.52, about $3,661 | about $1,126 |
Figures calculated from the Clean Energy Regulator’s factor table at the clearing house price.[1]
None of this is new information arriving suddenly. The battery factor under the Small-scale Renewable Energy Scheme has already stepped twice: 9.3 per kWh across 2025, 8.4 for January to April 2026, then 6.8 from May 2026.[1] The schedule was published in advance each time.
Is it the contract date or the installation date that locks in the rate?
The installation date, not the quote or deposit date. The Clean Energy Regulator calculates battery certificates from usable capacity and installation date, monitors those dates, and warns that improperly created certificates can attract enforcement action.[1] A December signature commissioned in January earns 5.7 per kWh.
Solar PV has a deeming period that smooths its rate across a calendar year. Batteries do not, which is why the battery number steps mid-year on 1 July as well as on 1 January.[1]
On a 13.5 kWh unit, a commissioning slot that slides from 29 December to 6 January costs about $594 of certificate value. Ask for the commissioning date in writing, and ask the installer to state on the quote which factor the rebate line assumes. If they have written 6.8 against a job their crew cannot energise until February, the shortfall lands on you.
Should you rush an install before 31 December 2026?
For most households, no. Sign in December because the quote is good, not because a calendar page turns.
The regulator’s own wording matters here. It says the factor is “adjusted in line with falling battery costs over time” so that the discount stays at around 30% of the upfront cost of installing a battery.[1] Read that plainly: the cut is designed to track hardware getting cheaper, so a buyer in mid-2027 paying less for the same kilowatt-hours can land at a similar net price. That is design intent, not a price guarantee, and nothing obliges manufacturers to drop prices in step. Treat it as a reason not to panic rather than a reason to wait.
Now put the $594 next to the numbers a rushed decision actually moves. A retrofit onto existing solar without a hybrid inverter carries an inverter swap of roughly $3,000 or more, unless the battery has an inverter built in.[5] That single line item is five times the December-to-January rebate gap, and it is the one most commonly missing from a headline quote.
Installer and hardware choice moves more again. On the SolarQuotes battery price index, a Tesla Powerwall 3 with Gateway is listed at $10,000 after the federal rebate, a Sungrow SBR HV 12.8 kWh at $8,100 and a Fox-ESS CQ7 13.92 kWh at $3,900, all excluding installation.[5] That is a spread of more than 2.5 times for near-identical usable capacity. Choosing the December-available installer over the right one can cost thousands. The rebate step costs hundreds.
And in one state, waiting is arithmetically better. More on that below.
Does a bigger battery earn a bigger rebate per kWh?
No. The factor applies at 100% for the first 14 kWh of usable capacity, at 60% for every kWh from 14 to 28 kWh, and at only 15% for every kWh from 28 to 50 kWh.[1] The last kWh of a 40 kWh system earns roughly a seventh of what the first kWh earns.
That changes how you should hear an upsell. Capacity above 14 kWh is not buying subsidy at the headline rate, so judge it on your evening load and your export limits instead.
The eligibility bounds are wider than the subsidy bounds. Batteries of 5 to 100 kWh nominal capacity qualify, with the payment calculated on the first 5 to 50 kWh of usable capacity, and the unit must connect to new or existing solar and be VPP-capable. Joining a virtual power plant is optional for the federal rebate.[4]
Households planning past 28 kWh mainly to harvest certificates are the group this taper punishes. Stopping at 28 kWh, or splitting capacity across two addresses, keeps more of every kWh inside the 100% and 60% tiers.
Can you stack a state battery rebate on top of the federal one?
In Western Australia, yes. Elsewhere the state money is usually a virtual power plant payment rather than a rebate, which changes both the size and the strings.
The WA Residential Battery Scheme pays $130 per kWh to a maximum of $1,300 for Synergy customers and $380 per kWh to a maximum of $3,800 for Horizon Power customers, stacks with the federal rebate, and is capped at 100,000 rebates released in rounds.[4] WA’s scheme does require joining a VPP.
South Australia is the timing exception. The REPS VPP incentive of up to $2,050 ran out of funding for most households in May 2026 and stayed open only to priority groups such as pensioners and health care card holders, with a top-up expected at the start of 2027.[4] If that $2,050 is what makes your payback work, a January install at 5.7 per kWh beats a December install at 6.8 by roughly $1,456.
NSW pays peak reduction certificates worth about $60 per kWh for batteries of 2 to 28 kWh, but households typically keep only around 60% after compliance and administration costs, which caps the realistic payment near $1,000.[4] Your total depends on postcode at least as much as on date.
When does the federal battery rebate scheme end altogether?
After 2030. The factor falls twice a year from 2027: 4.6 then 4.1 in 2028, 3.6 then 3.1 in 2029, 2.6 then 2.1 in 2030, and the small-scale scheme concludes.[1]
A glide path with every step published years ahead is not a closing-down sale. That is exactly what makes “sign before the rebate drops” a sales line rather than news.
One thing the wind-down does not do is show up on your power bill. Battery STCs are bought by the Department of Climate Change, Energy, the Environment and Water rather than by liable entities, and are excluded from the small-scale technology percentage, so no battery subsidy cost is passed to retailers or households.[3]
The settings do keep moving, though. On 5 August 2026 the government announced small-scale solar PV eligibility expanding from 100 kW to 1 MW for installs from 1 October 2026 subject to regulations, with applications opening mid-to-late November 2026.[3]
Which batteries sit where on the rebate curve
Prices below come from the SolarQuotes battery price index, after the federal rebate and excluding installation, checked 16 September 2026.[5] A delivered figure is materially higher.
| Battery | Usable capacity | Where it sits on the curve | Index price after rebate | Where to buy |
|---|---|---|---|---|
| Tesla Powerwall 3 | 13.5 kWh | Entirely in the 100% tier; integrated inverter | $10,000 incl. Gateway | Check price on Amazon |
| Fox-ESS CQ7 | 13.92 kWh | Sized almost exactly to the 14 kWh ceiling | $3,900 | Check price on Amazon |
| Sigenergy SigenStor | 13 kWh | 100% tier; integrated inverter | $8,000 | Check price on Amazon |
| Sungrow SBR HV | 12.8 kWh | 100% tier; needs a hybrid inverter priced separately | $8,100 | Check price on Amazon |
| AlphaESS Smile-M5 | 10 kWh | 100% tier, smaller certificate count | $3,700 | Check price on Amazon |
Sized to the 14 kWh full-rate ceiling
The Tesla Powerwall 3 at 13.5 kWh and the Fox-ESS CQ7 at 13.92 kWh both sit under the 14 kWh line, so every kWh earns the top factor. On that 13.5 kWh figure the support falls from about $3,672 to about $2,808 between now and the second half of 2027.[1]
Retrofits with no hybrid inverter
If your existing string inverter has to be replaced, that is roughly $3,000 or more on top.[5] The Sigenergy SigenStor 13 kWh and the Powerwall 3 carry integrated inverters and avoid it. The Sungrow SBR HV 12.8 kWh at $8,100 does not, so its $8,100 index price is not comparable to the SigenStor’s $8,000 until you add the inverter.[5] On a retrofit, Sungrow is the one that loses here.
Smaller, and across the taper
The AlphaESS Smile-M5 at 10 kWh draws about $2,720 in federal support now and about $2,280 from January 2027.[1] Smaller in dollars, identical in proportion. Above the line, a 20 kWh unit such as the Sungrow SBH200, listed at $11,700 on the same index, splits into 14 kWh at the full factor plus 6 kWh at 60%.[5]
So should you sign in December or wait for January?
Sign in December only if the quote stands up without the deadline. The regulator adjusts the factor as hardware prices fall to hold the discount near 30%, so a 2027 install can land at a similar net price — and a $3,000 inverter swap or a reopening state scheme moves more money than $594.
By postcode: Horizon Power customers in WA with a rebate in hand and a commissioning slot before 31 December have the clearest case to move now, because $3,800 of state money plus 6.8 per kWh is the best combination on offer. South Australian households counting on the REPS top-up expected at the start of 2027 have the clearest case to wait. Everyone else should price the delivered total with the inverter in it, then pick the installer, then take whichever commissioning date that installer can honestly hold.
The home battery rebate 2027 cut is a published schedule, not a closing-down sale. Judge the Tesla Powerwall 3 and Sigenergy SigenStor on the inverter they save you, the Fox-ESS CQ7 and AlphaESS Smile-M5 on delivered price, and the Sungrow SBR HV only once its hybrid inverter is quoted in full.
