Home Battery Rebate & Size Calculator (Australia)Home Battery Rebate & Size Calculator for Australia
Enter your postcode, solar size and daily usage to estimate the federal battery rebate (STCs), how much a battery raises self-consumption and cuts your bill, the payback period and which size works best. Includes the tiered rebate from May 2026 and the six-monthly factor cuts. Nothing is sent.
Figures on this site are estimates from Clean Energy Regulator rules, NASA climate data and assumed prices. They are not quotes and the rebate is not guaranteed. The rebate (STCs) is created by your installer and passed on as a discount; its value depends on the number of STCs and the STC price at the time. Get quotes from several installers and check your retailer's tariffs and official federal and state information before buying.
How it works
- Monthly radiation and temperature for the nearest city are converted to output on your roof after heat, dust and equipment losses.
- Each month is split into sunny, average and cloudy days. Every hour, solar powers the home first, surplus charges the battery, the battery covers the evening, and the rest is exported or bought. The result is compared with no battery.
- Battery benefit = savings on bought power − lost feed-in income. Payback compares this with the battery price after rebates. Battery capacity declines 1.5% a year.
FAQ
What is the Cheaper Home Batteries Program?
A federal discount for home batteries that started on 1 July 2025. Small-scale technology certificates (STCs) are created based on the battery's usable capacity, and your installer takes them off the price. It is designed to cover about 30% of the upfront cost.
How much is the battery rebate?
Usable capacity × the STC factor (6.8 for May–December 2026) gives the number of STCs; multiply by the STC price. From May 2026 the factor applies in full up to 14 kWh, at 60% from 14 to 28 kWh and 15% from 28 to 50 kWh. For example, a 13.5 kWh battery installed in November 2026 earns 91 STCs, about $3,458 at $38 each.
What size battery should I get?
Bigger batteries raise self-consumption, but capacity beyond what you use overnight sits idle, and the rebate tapers above 14 kWh. The calculator compares nine sizes and shows the one with the best net result over the period.
Is my input sent anywhere?
No. Everything is calculated in your browser.
Sources: battery STC factors, size tiers, solar zones and deeming periods from the Clean Energy Regulator; postcode zones from the CER table (as of 1 January 2020); solar radiation and temperature from NASA POWER (2001–2025 monthly climatology). Calculated by this site (checked 2026-11-01).