The STC line on a heat pump quote looks simple. It is the number of certificates multiplied by a dollar value, taken off the price. Behind it sits an assignment, a registry claim and a sale. Understanding the pieces explains both who benefits and why numbers differ.
How it appears on a quote
A well-presented quote shows the gross installed price, the number of STCs, the dollar value per STC, and the discount. A line that only says “government rebate” hides the information you need to compare. See how much the STC discount is on a quote for solar and how the discount works upfront.
Who gets it
You do, as a lower price. The installer receives the right to create and sell the certificates, which is why you sign an STC assignment form. The installer carries the work of creating the claim and the risk that a certificate is refused. In return they fund the discount up front. For the installer-side view on risk and pricing, see how installers price after STCs.
Why it can be lower than expected
- The count is smaller than a rule of thumb. Counts come from the registered model, zone and installation type, not from tank size alone.
- A different installation type. A new installation and a replacement are treated differently. See the installation type guide.
- The zone. It follows the install postcode.
- The installation year. The scheme runs to 31 December 2030 and counts shrink as the end approaches. See will it go down in 2027.
- The STC price assumed. At the time of writing the market has been roughly $38 to $40 and an installer may deduct a margin or use a lower figure to protect themselves.
- A different model. The unit supplied is not the one the estimate assumed.
- A shared incentive. Some installers keep part of the value to cover the cost of claiming. Ask.
Questions to ask
- How many STCs are you claiming, and at what dollar value each?
- Is that count confirmed from the register for this exact model?
- Is the discount fixed when I sign?
- What happens if a certificate is rejected?
From the desk: if the discount looks low, ask for the count first. A count that is far from the calculator’s estimate is the quickest sign something is off, in either direction.
What this means for installers
Be specific on quotes. State the count, the value and what is fixed. Customers who understand the line rarely feel shortchanged. Check counts against the heat pump STC calculator, and see pricing, how it works and the hot water STC pillar.
A worked check
Say your quote shows 20 STCs at $39, a discount of $780. If the calculator gives 24, ask why. The difference could be a different installation type, a different model on the register or a conservative price assumption. A good installer will explain it in a sentence.