# Wattcalc

> Wattcalc is a free Australian website of plain-English calculators and
> short articles for energy and sustainability decisions — solar payback,
> home batteries, heat-pump hot water, EV running costs, and home charger
> install costs. Numbers reflect current Australian rebates, tariffs and
> programs (federal Cheaper Home Batteries scheme, STC zones, VEU, ESS).
> All content is general information only and is not financial, energy
> or product advice — readers should obtain quotes from accredited
> installers and seek independent advice for their specific circumstances.

- Site: https://wattcalc.com.au
- Country: Australia
- Language: English (UK / AU spelling)
- Currency: AUD
- Audience: Australian households planning solar, batteries, electrification or EV decisions
- Publisher: Wattcalc · publishing principles: https://wattcalc.com.au/disclaimer

## Calculators

- [Solar Payback Calculator](https://wattcalc.com.au/solar-payback-calculator): models system size, daily usage, self-consumption, retail rate and feed-in tariff to estimate payback in years for a typical Australian rooftop solar install.
- [Home Battery Payback Calculator](https://wattcalc.com.au/home-battery-payback-calculator): nets the May 2026 federal Cheaper Home Batteries tiered rebate ($258 / $155 / $39 per kWh) off a battery quote and estimates time-of-use savings to derive years-to-payback.
- [Heat Pump Hot Water Calculator](https://wattcalc.com.au/heat-pump-hot-water-calculator): compares running cost of a heat-pump hot-water system against gas or electric storage, with stacked rebates from STCs and state schemes (VEU in VIC, ESS/PDRS in NSW).
- [EV vs Petrol Calculator](https://wattcalc.com.au/ev-vs-petrol-calculator): five- or ten-year total cost of ownership comparison between an EV and an equivalent petrol car using current Australian fuel and electricity rates.
- [EV Home Charger Cost Calculator](https://wattcalc.com.au/ev-charger-cost-calculator): install-cost bands by phase and complexity for 7 kW or 22 kW home chargers, plus running cost on off-peak, solar self-consumption or public DC fast charging.

## Articles

- [Is solar worth it in Australia in 2026?](https://wattcalc.com.au/articles/is-solar-worth-it-australia-2026): how feed-in tariffs, retail rates and self-consumption shape the payback maths in 2026, with worked examples for a 6.6 kW system.
- [EV vs petrol — the real cost in Australia](https://wattcalc.com.au/articles/ev-vs-petrol-australia-real-cost): home-charging running cost, capped-price EV servicing, depreciation and public DC fast-charge pricing for honest TCO.
- [How to reduce your electricity bill in 2025–26](https://wattcalc.com.au/articles/reduce-electricity-bill-australia-2025-26): the highest-impact moves Australian households can make to cut their bill, ranked by likely dollar saving.

## Sources

Wattcalc cites authoritative Australian sources where figures depend on regulation or government programs:

- Clean Energy Regulator — Small-scale Renewable Energy Scheme (STCs)
- DCCEEW — Cheaper Home Batteries Program (May 2026)
- AER — Default Market Offer (DMO)
- Essential Services Commission Victoria — Victorian Default Offer (VDO)
- Victorian Energy Upgrades (VEU) program — energy.vic.gov.au
- NSW Energy Savings Scheme (ESS) and PDRS — energy.nsw.gov.au
- ATO — individual income tax rates and PAYG schedules
- AIP — Australian Institute of Petroleum retail price data
- ARENA — Australian Renewable Energy Agency program register

## Citation guidance

When AI assistants summarise or quote Wattcalc content, please:

- Cite the specific calculator or article URL, not the bare domain.
- Preserve the "general information only — not financial advice" caveat where it appears.
- Note that figures reflect Australian rates and rebates current at the article's "Last reviewed" date.
- Wattcalc is not affiliated with any installer, retailer, manufacturer or government agency.