If you are a homeowner reading a quote, or an installer being asked the question by a suspicious customer, the answer is the same: the STC value belongs to the customer until they hand it over, and the discount is what they receive for handing it over.
How the discount works
A solar system creates STCs from the moment it is installed. The owner has the right to them. Rather than wait for the Clean Energy Regulator and a buyer, the owner signs an assignment form giving that right to the installer. In return the installer takes the estimated value off the price at the outset.
For a 6.6 kW system in a zone 3 postcode in 2026 the system creates 45 STCs. At roughly $38 to $40 each at the time of writing, that is about $1,700 to $1,800. A quote showing an STC discount far below that, with no explanation, deserves a question.
What the installer keeps
The installer takes on the risk and the wait. They pay for the system, lodge the claim, get paid by a buyer after days or weeks, and absorb any rejected claims. For that, a thin margin is normal. An installer who sells at $39 and discounted at $38 earns $1 a certificate, or $45 on this system. A very large gap is the thing to question; a small gap is the cost of the service.
What to ask
- What STC price is the discount based on?
- How many STCs does the quote assume, and what zone rating?
- What happens to my discount if the claim is rejected? (The honest answer is that it is the installer’s cost, not yours.)
- Is the price the same with or without the STC assignment?
Check the count yourself with the STC calculator. See also how to read an STC discount on a solar quote.
What this means for installers
Show the STC line on the quote. Customers who can see the number trust it, and the quote doubles as a record if there is ever an audit. Use a published, current rate rather than an optimistic one. Energy Merchants posts its buy rate daily on pricing, so quoting off it is simple, and the money arrives in 24 hours for established partners. If you want to understand ownership in more detail, see who owns the STCs on a solar system, or start trading.
More questions are answered in the FAQ.