The battery rebate gets smaller on 1 January 2027. Here is what that means for your quote

If you are pricing a battery, 1 January 2027 is a date worth understanding before a salesperson brings it up. That is when the federal discount gets smaller: roughly $560 to $600 less off the price of a 13.5 kWh battery. The catch is that the date deciding your rate is not the day you sign.

What is changing

On 1 January 2027, the STC factor in the Cheaper Home Batteries Program falls from 6.8 to 5.7. For a battery with 13.5 kWh of usable capacity, that means 15 fewer certificates.

The program has discounted batteries installed since 1 July 2025. Since a rule change on 1 May 2026, the discount falls every six months until 2030, which the government says keeps it at around 30% of the upfront cost as battery prices fall.

The STC factor sets how many certificates each kilowatt-hour of usable capacity creates:

• 6.8 for May to December 2026
• 5.7 for January to June 2027
• 5.2 for July to December 2027
• then 4.6, 4.1, 3.6, 3.1 and 2.6, reaching 2.1 for July to December 2030.

Not every kilowatt-hour counts equally. The first 14 kWh of usable capacity counts in full, capacity above 14 kWh and up to 28 kWh counts at 60%, and capacity above 28 kWh and up to 50 kWh counts at 15%. The total is rounded down to a whole number of STCs.

The Clean Energy Regulator's STC Clearing House price is capped at $40 excluding GST, and open market prices vary daily, so we value each STC at $37 to $40. For more detail, see how the federal battery rebate works.

Worked examples

Values use $37 to $40 per STC, rounded to the nearest $10. The drop ranges from about $410 to $440 on a 10 kWh battery to about $700 to $760 on a 20 kWh battery. Your actual discount depends on the STC price your installer uses. Try other sizes in our battery rebate calculator.

From 1 July 2027 the factor is 5.2, and a 13.5 kWh battery creates 70 STCs, worth about $2,590 to $2,800.

Why the compliance certificate date matters

The factor depends on when the battery is installed, and the date that counts is the one on the certificate of electrical compliance your electrician issues once the system has been tested. The Clean Energy Regulator requires installers to take a final completion photo that matches the test date on that certificate, and says installers must not return to site later to take photos or alter documents to match them.

So signing or paying a deposit does not lock in the 6.8 factor. Picture a battery sold in November for a mid-December install. Stock arrives late, the job and its certificate slip into January, and the discount is now worked out at 5.7. Someone has to cover the gap.

How to avoid being rushed

A looming cut is an easy sales line. In July the ACCC found that battery complaints had more than doubled, including from people sold systems that did not suit them. See our report on those complaints.

Before you sign:

• Ask whether the price is fixed. If the job finishes after 31 December, will the price rise, and who pays the difference? Get the answer in the contract.
• Ask for a realistic install date in writing, and what could delay it, such as stock, switchboard work or approvals.
• Do not pay a large deposit to "lock in" the rebate. A deposit cannot fix the factor. Only the installation date can.
• Size for your home. The government's own advice is that bigger is not always better. Read what size battery you need and is a home battery worth it.
• Compare quotes on final price. A big discount line does not always mean a cheaper battery. Get more than one quote, as the government recommends, and see sales tactics to walk away from.

What it means for you

If you were already planning a battery and a reputable installer can finish well before Christmas, the higher factor is worth having. If beating the deadline means rushing, the few hundred dollars at stake may matter less than choosing the right battery and installer. Waiting does have a cost, though, and it grows every six months.

Check what your state adds on top in our rebates overview, then request quotes with enough time to compare them.

Our take

We would not ignore the step-down, and we would not let it run the conversation either. On a 13.5 kWh battery it is a few hundred dollars: real money, but a small slice of a discount worth $3,370 to $3,640. The questions above are the ones we would put to every installer, and we would want the answers in the contract, not just the conversation. If an installer cannot give straight answers on price, install date and deposit, that tells you something useful about them, whatever the date.