Unlike a solar PV system, there is no simple “kW times zone times years” formula for a heat pump that you can run in your head. The count comes from the product’s registration data.
The inputs
- The model. Each registered heat pump or solar water heater has a listing with its rated output.
- The climate zone. The install postcode determines the zone and its effect on the calculation. See the postcode zone guide.
- The installation type. New, replacement or additional, covered in the installation type guide.
- The year. The scheme runs to 2030, with deeming adjustments along the way.
How to get the number
- Use a calculator from a trader or the Clean Energy Regulator that takes the model and postcode.
- Check the registered product list for the model’s data.
- Confirm the count with your trader before you quote.
From certificates to dollars
Multiply the STC count by the rate. For example, 20 STCs at $38 to $40 is $760 to $800. In Victoria there may also be VEECs, which are valued separately, see heat pump VEECs in Victoria.
Sanity-checking a result
As a sanity check, compare the STC count against similar models you have installed before. A larger tank or higher output usually earns more, and a colder zone usually earns less. If a calculator gives you an outlier, check the model code and postcode. Calculators can be out of date after a product list change, so confirm important jobs with your trader before you promise a discount, and keep a screenshot of the result with the date.
One more check
If the quote also includes a Victorian VEEC discount, confirm that the STC count and the VEEC count both refer to the same model and install date. The two schemes read the product list separately, and a listing that is valid for one may not be valid for the other on the day you install.
What this means for you
Homeowners: ask the installer to show the STC count and the dollar value on the quote. Installers: standardise this in your quoting tool, and check the hot water STC page and the hot water checklist. See today’s rate when pricing, and heat pump hot water STCs explained.