Unlike solar panels, where the maths is size times zone times years, heat pumps are certified by model. Each registered unit has a tested energy performance, and the number of STCs it earns reflects the energy it is deemed to save or displace compared with the baseline system, in the climate zone where it is installed.
What sets the count
- The model. Each registered model has performance data lodged with the Clean Energy Regulator. Better performance and bigger capacity generally earn more.
- The zone. Hot water zones differ from solar zones. A cooler region typically sees a different outcome from a warmer one.
- The installation type. A new installation, a replacement of an electric or gas system, and an additional system are treated differently. Get this wrong and the claim is wrong. See the installation type guide.
- The year. Like other STC categories, the scheme winds down to 31 December 2030.
How to find the number
Ask your installer to show the count on the quote, or use the Clean Energy Regulator’s small-scale technology certificate calculator for hot water, entering your model and postcode. We do not publish a fixed table because the figure changes with each model.
Converting STCs to dollars
At the time of writing STCs have been roughly $38 to $40, with a $40 clearing house ceiling. So the discount is the count times that price, less any installer margin. A unit earning 25 STCs, for example, would be worth roughly $950 to $1,000.
From the desk: treat that 25 as an illustration only. Always use the registered figure for your exact model, zone and installation type.
Questions worth asking your installer
Ask for the model’s registered STC count for your postcode and installation type, ask what price per certificate is being applied, and ask whether any state certificates are included as well. Those three answers tell you most of what you need to compare quotes properly, and they take two minutes to get in writing.
What this means for you
If you are a homeowner, ask your installer for the STC count and the dollar value on the quote. If you are an installer, check the figure for every model before you price a job. The hot water STCs pillar and the resources hub cover how the claim runs, and pricing shows the current rate for certificates.