Two things could get cheaper while you wait: the hardware, and the rebate. Only one of them reliably goes the other way.
The rebate is a one-way street
The federal solar discount comes from small-scale technology certificates (STCs). The number your system creates is its size in kilowatts, multiplied by your zone rating, multiplied by a deeming period. That period is 5 years for systems installed in 2026, 4 years for 2027, 3 for 2028, 2 for 2029 and 1 for 2030, and the scheme ends on 31 December 2030. See how the deeming period works year by year.
So for a 6.6 kW system in a zone 3 city such as Sydney or Brisbane, the count is about 45 STCs in 2026 and about 36 in 2027. At the time of writing STCs have been trading around $38 to $40, so that is a swing of roughly $350 to $360 on the discount alone, and it widens every year after. The full table is in how much will STCs fall next year.
What about panel prices?
Panel and inverter prices have been low and relatively stable. A fall large enough to cancel a 20 percent cut in the discount, then another 25 percent the year after, is not something anyone should plan around. If you want to see where your quote sits, what an STC is worth in 2026 explains how the dollar value is set.
When waiting does make sense
- You do not have the budget this year. A rebate you cannot use is worth nothing. Do not stretch to buy by 31 December.
- Your roof or switchboard needs work first. Fix the underlying problem and then install, rather than installing onto a problem.
- You are weighing a battery as well. The battery discount has its own schedule. See the battery rebate and the 1 January 2027 step.
- Your installer is rushed. A late-year pile-up is real, and a hurried install is a worse deal than a slightly smaller discount. See the December 2026 demand pull-forward.
Buying before the deeming period drops
If you do want the higher discount, the date that counts is the installation date, not the date you sign the quote. A quote signed in November for a January install earns the 2027 count. Ask your installer for an installation date in writing and a clear fallback if weather or grid approval pushes it. The detail of what changes on 1 January is in STC deeming period 2027: what changes in January.
What this means for you
Run your own numbers with the STC calculator, once for 2026 and once for 2027, and compare the difference with what you would save on bills in the extra months you would be waiting. If you are an installer being asked this question, the STC trading overview and pricing show how the certificates behind the quote are settled.