How Residential HPWH Results Become STCs, VEECs, and ESCs
Residential HPWH scheme registrations use AS/NZS 4234 modelling to estimate annual energy savings. Those results are then converted into certificate outcomes under the relevant scheme rules.
Target schemes
Residential HPWH products may be registered for SRES, VEU, and ESS. SRES is administered by CER and uses STCs, VEU uses VEECs, and ESS uses ESCs.
Each scheme has its own application process, forms, evidence requirements, and calculation method.
Modelling basis
Residential modelling usually uses AS/NZS 5125.1 heat pump performance test data, AS/NZS 4692.1 tank heat loss data, tank geometry, fitting locations, product control settings, AS/NZS 4234 annual simulation, and the climate zones and load profiles required by each scheme.
The same product evidence can often support more than one scheme, but each scheme still needs its own submission package.
What the model produces
The model produces annual performance outputs, including annual energy consumption, energy savings compared with the reference electric water heater, minimum delivery temperature, and scheme-specific values used in certificate calculations.
The model must meet scheme criteria before an application can proceed.
How STCs are derived
For SRES, CER uses approved modelling outputs to determine how many STCs a registered product can create. The final public listing depends on the submitted model, climate zone results, and CER acceptance.
EnergyAE prepares modelling evidence and application material to support the CER registration pathway.
How VEECs and ESCs are derived
For VEU and ESS, certificate quantities depend on scheme calculation methods and the modelled performance values used by the scheme.
The process involves modelling the product under the required AS/NZS 4234 conditions, checking minimum delivery temperature and energy savings criteria, preparing product application evidence, and submitting or supporting submission through the relevant scheme pathway.
If the regulator asks questions, EnergyAE helps respond where the request relates to modelling, test evidence, or document consistency.
Common reasons results change
Certificate outcomes can change when control settings change, tank heat loss evidence changes, model names or variants are consolidated, test report values are revised, or a different tank or heat pump variant is included.
Results can also change when the target scheme uses a different AS/NZS 4234 version or calculation method.
What EnergyAE needs from you
Confirm which schemes you want to target before modelling starts. Also confirm the exact product models, tank variants, brand names, and control settings that should appear in the final applications.