Should you buy a battery now or wait?
By Sithum Imarsha Last reviewed
A 13.5 kWh battery signed off by 31 December 2026 gets a $3,367 rebate. Wait until 1 January 2027 and it gets $2,812, so you lose $555. Add the bill savings you miss, and the installed price must fall by about 6.7% for waiting to pay off.
Your result
Rebate you lose by waiting
$555
May – Dec 2026: $3,367 → Jan – Jun 2027: $2,812
- Rebate now
- $3,367
- Rebate if you wait
- $2,812
- Cost after rebate now
- $8,783
- Cost after rebate later
- $9,338
- Bill savings missed
- $261
- Price must fall by
- 6.7%
Waiting costs you about $816 at these inputs. It counts the rebate, the price change you typed and 3 months of bill savings.
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DeadlineHave it signed off by 31 December 2026. Sign the quote by about 19 November 2026. A signed contract does not lock the rebate.
How we calculated this
| Install date | Rebate | Rebate lost | Cost after rebate | Cost of waiting | Price must fall |
|---|---|---|---|---|---|
| May – Dec 2026 | $3,367 | $0 | $8,783 | $0 | 0.0% |
| Jan – Jun 2027 | $2,812 | $555 | $9,338 | $816 | 6.7% |
| Jul – Dec 2027 | $2,590 | $777 | $9,560 | $1,559 | 12.8% |
| Jan – Jun 2028 | $2,294 | $1,073 | $9,856 | $2,376 | 19.6% |
| Jul – Dec 2028 | $2,035 | $1,332 | $10,115 | $3,156 | 26.0% |
| Jan – Jun 2029 | $1,776 | $1,591 | $10,374 | $3,936 | 32.4% |
| Jul – Dec 2029 | $1,517 | $1,850 | $10,633 | $4,717 | 38.8% |
| Jan – Jun 2030 | $1,295 | $2,072 | $10,855 | $5,460 | 44.9% |
| Jul – Dec 2030 | $1,036 | $2,331 | $11,114 | $6,240 | 51.4% |
| After 2030 (no rebate) | $0 | $3,367 | $12,150 | $7,797 | 64.2% |
Rebate on each date
The rebate uses the same maths as our battery rebate calculator: usable kWh, weighted in bands, × the STC factor for the install period, rounded down, × the STC price. The date that counts is the day the certificate of electrical compliance is issued, not the day you sign.
$3,367 now, $2,812 later
Rebate you lose
Rebate now − rebate later.
$3,367 − $2,812 = $555
Price later
Price today × (1 + price change a year) ^ (months waited ÷ 12). With 0% it stays the same.
$12,150 → $12,150 after 3 months
Bill savings you miss
While you wait, you pay for grid power the battery would have covered. We use the same saving as the rebate calculator: 365 × (kWh discharged a day × import rate − kWh charged a day × feed-in rate), then × months waited ÷ 12.
$1,042 a year → $261
Cost of waiting
(Cost after rebate later − cost after rebate now) + bill savings missed. Above zero, waiting costs you money.
$9,338 − $8,783 + $261 = $816
Break-even price fall
The price must fall by the rebate you lose plus the savings you miss. As a share of today's price, that is the fall that makes waiting come out even.
$816 (6.7%)
Deadline
The install must be signed off by the last day of the period. We take your quote to sign-off weeks off that date. The CER says to confirm the install is possible and the quoted price will be honoured before you rely on a date.
31 December 2026, order by about 19 November 2026
| Index month | 10 kWh | 20 kWh |
|---|---|---|
| Aug 2025 | $8,260 | $14,120 |
| Feb 2026 | $8,650 | $14,700 |
| Aug 2026 | $7,784 | $14,972 |
Industry figures from an installer network, not official, and already after the rebate. They moved with the rebate cuts, so they are not a price trend. We show them so you can judge your own price change figure.
| Value | Default | Source | Checked |
|---|---|---|---|
| Price change a year | 0% | No official trend for home batteries. Type your own. | Our choice |
| Quote to sign-off | 6 weeks | No official or dated source found | Estimate |
| Installed price | $900 per kWh | Same default as the rebate calculator | Estimate |
| Home battery price (CSIRO) | $1,100 | $11,000 for a 5 kW / 10 kWh system, installed, before subsidies. CSIRO GenCost 2025-26 Final Report, 15 Jul 2026, p 45 | Official source |
Sources
- Clean Energy Regulator: Solar batteries
- Clean Energy Regulator: Battery rebates are changing 1 May 2026
- DCCEEW: Cheaper Home Batteries Program
- DCCEEW: Small-scale technology certificates for batteries
- Canstar: electricity cost per kWh
- EnergyPlans: solar feed-in tariffs July 2026
- OTTER: Tasmanian feed-in tariffs
- WA legislation: Synergy A1 tariff, charges amendment by-laws 2026 (SL 2026/140)
- Solar Choice: Battery Price Index
- CSIRO: GenCost 2025-26 Final Report
The rebate steps down every six months
The federal battery rebate is paid in STCs. The number of STCs per kWh falls on 1 January and 1 July each year until the end of 2030. So the same battery gets a smaller rebate each time you cross a step date.
Waiting costs more than the rebate you lose
- The rebate you lose. The difference between the rebate now and on the later date.
- The bill savings you miss. Every month without the battery, you buy grid power it would have covered.
- The price change. If prices fall far enough, waiting can still come out ahead. If they rise, waiting costs more.
The calculator adds all three. The “price must fall by” figure is the one to check. It is how far the installed price has to drop by the later date for waiting to break even.
Nobody knows the price trend
There is no official figure for how home battery prices change. CSIRO reports falling costs for grid-scale batteries, which is a different market. Installer surveys show prices after the rebate moved with each rebate cut. So the calculator starts at 0% and lets you type your own view.
The date that counts
The install date is the date on your certificate of electrical compliance. A signed contract does not lock the rebate. Before a step date:
- Ask the installer when the job will be signed off, not when it will start.
- Leave extra weeks. Installers were several times busier than normal before the May 2026 change.
- Compare the same scope on both dates. A new inverter or switchboard work changes the price.
Check before you decide
The rebate rules come from the Clean Energy Regulator and DCCEEW, linked under “How we calculated this”. Rules can change. This page shows them as at the “Last reviewed” date below.
Questions
How much will the rebate drop on 1 January 2027?
For a 13.5 kWh battery, from $3,367 to $2,812: $555 less. The rebate falls by a set step every six months, so the drop is known in advance.
When is the deadline to get the rebate before the 1 January 2027 drop?
The install must be signed off by 31 December 2026. Allow for installer lead times: the calculator shows when to order.
Does signing the contract before the drop lock in the rebate?
No. The rebate uses the date your certificate of electrical compliance is issued, not when a contract is signed. The CER says to confirm the install is possible and the quoted price will be honoured before the change.
Will battery prices fall if I wait?
Nobody publishes an official price trend for home batteries. CSIRO reports falling costs for grid-scale batteries only. Installer surveys show prices after the rebate moved with the rebate cuts. So the price change starts at 0%. Type your own if you have a reason to.
Why does waiting cost more than the lost rebate?
While you wait, you keep paying for grid power the battery would have covered. The calculator adds those missed bill savings to the rebate you lose.
Are installers busy before each drop?
They were before the May 2026 change. CER data shows over 85,000 batteries installed in April 2026, several times a normal month. Leave extra weeks if you are close to a step date.
What if my quote changes the scope?
Compare the same job on both dates. A hybrid inverter or switchboard upgrade can be in one quote and not the other.