Australian households and small businesses installed record amounts of rooftop solar capacity in December, even as the boom in home batteries continued, with 4.3 gigawatt hours of storage capacity added in 2025.
Data from Green Energy Markets points to 28,800 rooftop systems added in the month of December, translating to a record monthly capacity of 328 megawatts (MW), beating the previous highest monthly total of 318 MW in November, 2023.
According to GEM, the market was hot for both residential and commercial scale rooftop systems, although the annual total reached just 2.82 GW, a 10 per cent fall from the previous year.
The home battery market continued to thrive, thanks to the federal government’s Cheaper Home Batteries rebate, and some supportive state schemes, with 42,000 new systems registered in the month of December, representing total capacity of 1.2 GWh.
That takes the total installed in the 2025 calendar year to 184,000, or a total of 4.3 GWh of nominal capacity. To put that in some perspective, Australia’s total grid-scale battery installations totalled 3,116MW and 6,415MWh in the 12 month to June 30 last year.
- GEM expects the home battery boom to continue apace, at least in the short term given that proposed changes to the design of the battery rebates will not come into effect until May 1.
“The rebate will taper by battery size, meaning smaller typical household batteries will retain a higher proportion of the rebate, while larger systems will see a reduced per-unit subsidy,” it notes.
“These changes suggest a lower effective STC benefit per battery installation over time, which may bring forward some demand into early 2026.”
GEM says the battery boom has translated into another lift in the average size of rooftop solar system, now at 9.64 kW, as households focus on self consumption, and eye more solar capacity to fill their large batteries.
- It says it is the biggest step-up in rooftop solar sizes in more than a decade, in fact since 2013 when a multiplier that incentivised smaller systems under 1.5 kW was removed.
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- “Both the smallest and largest capacity bands (<5kW and >14kW) recorded a higher number of annual system registrations compared to last year,” its report said. “All the mid-range bands (<5kW – <14kW) saw a decline in annual system numbers.”
