The same question appears three ways: a solar installer STC clause, an STC clause in a solar contract and an STC refund clause. They describe one section of the contract and its fallback.
Why the clause matters
The STC discount is often a large share of the price. The certificates are created after installation, and their value can change between quote and claim. The contract needs to say who carries that risk, and who owns the certificates in the meantime. Customers own the right to create STCs until they assign it; see who owns STCs.
What the clause should cover
- Assignment. The customer assigns the right to create the STCs to you or your nominated agent, and signs the assignment form (form guide).
- The discount. State the dollar amount deducted and how it was calculated: system size, zone rating, deeming period and the date of installation. Our explanation shows the maths.
- Fixed or variable. Is the discount fixed when the contract is signed, or can it change if the number of STCs changes? A fixed discount is simpler, but the installer then bears the risk of a change.
- Eligibility. What happens if the system or the customer turns out not to be eligible? State it plainly.
- Failed or reduced claims. Who bears the cost if the Clean Energy Regulator rejects, delays or reduces the claim?
- Cancellation. What happens to the assignment if the contract is cancelled; see cancelling an STC assignment.
The refund clause
A refund clause covers what the customer repays, or what you refund, when an STC outcome differs from the quote. Write it so that:
- it is tied to a specific event, such as an ineligible system or a customer-caused delay
- the amount is calculated by a stated method
- it does not penalise customers for the installer’s own errors
Consumer law restricts unfair terms and misleading conduct, so a clause that lets you claw back money for your own mistakes is likely to be challenged. See consumer law for solar installers.
From the desk: the deeming period falls each year and the battery factor steps down every six months, so a quote written in December can be wrong by January. Put an expiry date on your quote, and write the installation date into the discount calculation.
Timing risk in practice
For rooftop solar the deeming period is five years for 2026 installs and four for 2027. For batteries the factor is 6.8 at the time of writing, stepping down to 5.7 on 1 January 2027. A job that slips across a boundary changes the certificate count. Use the STC calculator or battery STC calculator to check the number on the day.
What this means for installers
Have a solicitor draft the clause, then test it on a real job. See the wider contract template guide. For the settlement side, the pricing page shows the published rate and start trading explains how a claim is locked. More on the installers hub.