Your solar rebate got smaller on 1 January. Here is by how much.

The 30-second take

• The STC deeming period fell to five years on 1 January 2026, reducing the number of certificates every new solar system earns.
• A typical 6.6kW system in most metro postcodes is now worth roughly $1,700–$1,900 in STCs, at a certificate price of about $37–$39 — down from around $2,100.
• That is a drop of roughly $300–$400, and it happens every 1 January as the scheme winds down towards 2030.
• The certificate price itself floats, so your actual rebate depends on both the deeming period and what STCs are trading for when your system is registered.
• This is the solar panel rebate. It is a separate scheme from the Cheaper Home Batteries battery rebate, and the two step down on different schedules.

What a “deeming period” actually is

Australia’s rooftop solar rebate is not a cash grant. It is a certificate scheme, and understanding the mechanism is the difference between reading your quote properly and taking someone’s word for it.

When you install a solar system, it generates small-scale technology certificates — STCs — based on how much clean electricity it is expected to produce over a set number of years. That number of years is the deeming period. Your installer almost always claims the certificates on your behalf and passes the value through as an upfront discount on the invoice.

The Small-scale Renewable Energy Scheme is legislated to wind down to 2030, and the mechanism for winding it down is the deeming period. Every 1 January, the number of years shrinks by one. Fewer years deemed means fewer certificates, which means a smaller discount.

On 1 January 2026 the deeming period stepped down to five years. Nothing was announced, nothing was cancelled, and no politician made a statement — it is simply the scheme doing what the legislation always said it would do.

What it is worth in dollars

For a typical 6.6kW system in most metropolitan postcodes, the STC value now sits at roughly $1,700 to $1,900, based on a certificate price of around $37 to $39. Last year the same system was worth around $2,100.

So the practical effect is a reduction of roughly $300 to $400 on the upfront discount, depending on your postcode and the certificate price on the day.

Two variables move that number:

• Your postcode. Certificates are calculated using a zone rating that reflects how much sun your location gets. A system in Darwin earns more certificates than the same system in Hobart.
• The STC spot price. Certificates trade on a market. The price is not fixed, and a quote written when STCs were trading higher is not a promise about what they will be worth at registration.

Why your quote might not reflect it

Because the STC discount is applied by the installer and netted off the invoice, most homeowners never see the certificate maths. They see a single "after rebate" price. That is convenient, and it is also where confusion lives.

A quote that shows only a final number gives you no way to tell whether the rebate assumption behind it is current, or whether it was built on last year’s deeming period. It also gives you no way to compare two quotes properly, because you cannot see whether the difference between them is the hardware, the labour, or a more optimistic rebate assumption.

Ask for the STC value to be shown as its own line item, with the certificate count and the assumed price. Any competent installer produces that in seconds, because it is exactly what they submit when they claim the certificates.

“A quote that hides the rebate line is a quote you cannot actually compare.”

Does this change whether solar is worth it?

For most Australian households, no — and it is worth being precise about why rather than just reassuring.

A few hundred dollars off the rebate is a real cost, but it is small relative to the two numbers that actually drive a rooftop system’s return: what you pay per kilowatt of installed capacity, and how much grid electricity you avoid buying. Panel and installation costs have fallen far more over the life of the scheme than the deeming period has taken away.

The step-down does change the ranking of your priorities, though. When the rebate was larger, it could paper over a mediocre deal. As it shrinks each January, the quality of the deal and the quality of the install carry proportionally more of the outcome.

The part worth planning around

The deeming period is locked in at the point your system is installed and registered, not when you sign. In a market where good installers are booked out for weeks, a job quoted in November and installed in January crosses a step-down.

If you are buying in the last quarter of a calendar year, that is a conversation to have upfront: what installation date is realistic, and what happens to the price if it lands on the other side of 1 January. Get the answer in writing.

The other thing worth knowing is that this scheme is not the battery rebate. The Cheaper Home Batteries Program is a separate federal program with its own certificate factor and its own step-down schedule. If you are buying solar and a battery together, you are dealing with two different rebate clocks running at two different speeds, and your quote should show them separately.

What this means for you

If you’re a homeowner

• Ask for the STC discount as a separate line on every quote, showing the certificate count and the assumed price — not just an "after rebate" total.
• If you are buying between October and December, confirm the expected install date and what happens to the price if it slips past 1 January.
• Do not treat the annual step-down as a reason to panic-buy. The reduction is a few hundred dollars; picking the wrong installer costs more.
• If your quote covers solar and a battery, check that the two rebates are itemised separately. They are different schemes on different schedules.

If you’re an installer

• Quotes that itemise the certificate count, zone rating and assumed STC price close better in a declining-rebate market because they let the customer see you are not hiding anything.
• Q4 jobs need an explicit position on what happens if the install crosses 1 January. Silence on that becomes a dispute in February.
• As the rebate shrinks each year, price-led selling gets structurally harder. The differentiator moves towards demonstrable workmanship and accreditation.

Read next

• Understanding STCs
• How to read a solar quote
• Federal solar and battery rebates
• What system size actually suits your home

Sources

Every quantitative claim on this page traces to one of the sources below — government, regulator, market operator, or independent industry reference.

• Clean Energy Regulator — Small-scale technology certificates
• Clean Energy Regulator — Small-scale Renewable Energy Scheme
• DCCEEW — Renewable Energy Target