What happens to installers when the STC scheme ends

When the STC scheme ends on 31 December 2030, installers lose a discount that has funded a large share of the residential solar price for twenty years. The change does not arrive as a cliff, though. The deeming period shortens by a year every January, so the certificate value of the same system falls by 20 per cent in 2027, a further 25 per cent in 2028, and so on, to a single deemed year in 2030. Installers feel the scheme ending as five consecutive years of shrinking discount rather than one bad day.

That makes this a planning problem, not a prediction problem. The dates are fixed, the formula is published, and your own average job size and zone mix tell you what the revenue impact is. This guide gives you a model to run, the levers installers have, and a sequence for the next four years.

The glide path in numbers

Use the formula: STCs = kW x zone rating x deeming years. For a 6.6 kW system in Zone 3 (rating 1.382):

Assume a flat $38 for illustration; the clearing house ceiling is $40, so prices have little room above that. The discount per system falls by $1,368 between 2026 and 2030. For a customer that is the cost of the system rising by that amount, all else equal.

What it does to your revenue

Suppose you install 30 systems a month averaging 8 kW in Zone 3. The certificate value per job is 8 x 1.382 x years x $38, which is about $2,100 at 5 years, and $420 at 1 year. Across 30 jobs a month, the certificate value flowing through your business falls from about $63,000 a month in 2026 to about $12,600 in 2030. Whether that is a loss to you depends on whether it was a cost to the customer or a margin to you.

Three things usually happen:

1. Prices adjust. As discounts shrink, system prices to customers rise relative to the net price, and some demand drops.
2. Margins compress. Competitors cut to win, particularly in 2027 and 2028.
3. The market shifts. Demand moves to products with stronger incentives, notably batteries, and to retrofit and service work.

Levers installers have

Batteries. The Cheaper Home Batteries Program also steps down, now every six months, to 2030 (the factor is 6.8 for 2026 installs and 5.7 from 1 January 2027), but it is a larger ticket and it supports solar attachment. See the installer guide.

Hot water. Heat pump and solar hot water STCs, and VEECs in Victoria, give a second line of work with its own incentives. Our explainer on heat pump hot water STCs sets out the federal side.

Commercial solar. Above 1 MW the scheme moves to large-scale certificates, and the LRET also ends in 2030, so check the economics; the incentive is not a growth lever beyond 2030. For businesses up to 100 kW, and for mid-scale systems up to 1 MW installed from 1 October 2026 (mid-scale solar STCs), STCs continue to the end date.

Service and upgrades. An installed base of systems from 2010 to 2025 is ageing. Inverter replacements, monitoring, battery retrofits and panel upgrades are a recurring revenue base that does not depend on the certificate.

Efficiency in operations. With less margin per job in certificates, a rejected or delayed claim costs a larger share of margin. Better evidence capture and faster settlement matter more every year.

Cash flow through the decline

A smaller discount means a smaller certificate cheque per job, but the timing risk stays the same: you fund the work and wait for payment. As certificate value per job falls, the margin cushion against a failed claim also falls. Build a rule: no job leaves site without complete evidence, and no job is quoted without the install year’s STC count on the paperwork. Our claim rejection reasons guide lists the fixes.

A four-year plan

2026 to early 2027. Lock in jobs with firm install dates before 31 December. Add the install year to your quote terms. Set up your battery processes if you have not already.

2027. Re-price systems to reflect the 4-year deeming period. Push battery attach on every solar quote. Review your trader’s terms and rate.

2028 and 2029. Shift your mix toward products and services with durable demand. Reduce cost per job, because discount per job is falling.

2030. Expect a rush toward the last install dates. Make sure your claim processes can handle volume without quality loss, and confirm the regulator’s creation deadlines for end-of-scheme systems.

What customers will ask

Expect the same three questions every year. “Should I wait?” The answer is no on rebate grounds, since waiting only lowers the discount. “Will prices fall?” Equipment prices may, but the certificate step-down is known, so show both in the quote. “Will the scheme be replaced?” Nobody can promise that, and you should not either; say the scheme ends on 31 December 2030 and that you will not speculate about what follows. Clear, dated answers protect you from a customer who later claims they were promised a rebate that no longer exists.

Contracts and quotes that survive the decline

Put the deeming year and STC count in every quote, state that the discount depends on the installation date, and set a clause for what happens if the install slips past 31 December. For jobs that straddle a year end, agree in writing who bears the cost of the lower deeming period if delays are on your side. This is also where a trader’s rate lock helps: when the rate is locked on lodgement of a complete claim, your margin on a job is set once the claim is in, rather than moving with the market while you chase paperwork.

See also the answers on whether the solar rebate will end in 2030 and selling STCs before the deeming period drops.

What to do next

1. Build the revenue model from the table, using your own job mix.
2. Read what changes in January 2027 and the answer on when the STC scheme ends.
3. Review your settlement terms. Our STC trading pillar, the pricing page and the partner program show what a published daily rate and a named account manager look like.
4. Keep a clean evidence process now, so that the last year’s volume is not your hardest.