We use publicly available data from government agencies, energy regulators, and industry bodies. Key sources include:
Last verified: May 2026. We refresh this list whenever a major source changes.
Australia
- Electricity rates: Australian Energy Regulator (AER) Default Market Offer, state-specific retailer data
- Gas rates: AER, Essential Services Commission (VIC), state regulators
- Solar incentives: Clean Energy Regulator (STCs), state government programs (Solar Homes VIC, etc.)
- Solar production: Bureau of Meteorology solar irradiance data, PVWatts methodology
- Equipment costs: SolarChoice installer surveys (Feb 2026), industry data, manufacturer pricing
- Climate zones: Bureau of Meteorology climate classification
General
- EV efficiency: Manufacturer specifications, real-world consumption data
- Heat pump COP: Manufacturer data, climate-adjusted performance curves
- Petrol prices: Australian Institute of Petroleum and ACCC fuel monitoring data; FuelWatch (WA)
- Inflation/escalation: Reserve Bank of Australia, historical energy price trends
All assumptions can be inspected and overridden using the "Under the Hood" panel on the calculator.