This is a forecast question, and anyone offering a firm answer is guessing. What we can do is separate the parts that are known from the parts that are not.
What is known: the discount shrinks first
The STC discount is already on a downward path. Deeming years fall from 5 for 2026 installs to 4 for 2027 and to 1 in 2030, and the scheme ends on 31 December 2030. For a 6.6 kW system in zone 3 that means about 45 STCs in 2026 and about 9 in 2030. At roughly $38 to $40 per STC today, that is around $1,700 to $1,800 of discount falling to under $400, before any change in the market price. The scheme mechanics are in what happens to STCs in 2030.
So the net price rises a little each year purely from policy, if all else is equal. After the end date, the remaining few hundred dollars goes too.
What is not known: hardware and labour
Prices after 2030 depend on several things nobody can promise:
- Panel and inverter prices. They have fallen over the long run, but supply chains, tariffs and the exchange rate move them in both directions.
- Labour and compliance costs. Installation labour and approvals tend to rise over time.
- Demand. A rush before a rule change can lift prices, and a slump can lower them.
- Other incentives. New state or federal programs could replace STCs, or not.
So the honest summary is that the net price depends on whether hardware savings outrun the lost discount. For a modest system the discount in 2030 is small enough that it is unlikely to be the deciding factor, but in 2026 it still matters.
The more important maths
The discount is a one-off. The savings from running your own solar are every day for 20 years or more. A household that waits two years to chase a cheaper price gives up two years of lower electricity bills. In many homes that outweighs any plausible saving on the system. Use our STC calculator for today’s discount, then compare it with your annual savings. See also should I install solar now or wait.
What this means for you
If your payback works now, the discount and your savings favour acting sooner. If you are on the fence, run the numbers for both this year and next, and check the 2027 change. Batteries follow their own schedule, which you can check on the battery STC calculator. For the broader picture, read the homeowners guide. Installers watching volumes through the glide path can see pricing and STC trading.