New data from industry analysis firm SunWiz, released on July 10, 2026, indicates a notable shift in Australia’s rooftop solar landscape: the national average system size for new installations contracted to 10.01 kW in June 2026. This marks a 12-month low, down from 10.47 kW in May and a peak of 11.32 kW in April. The unexpected dip is primarily attributed to changes in the federal government’s Cheaper Home Batteries Program, which saw reduced rebate offerings from May 1, 2026.
The slight contraction in average system size comes after a period of sustained growth, where Australian households increasingly opted for larger solar arrays to meet escalating energy demands. The Clean Energy Regulator (CER) reported that the average small-scale solar system size in Q1 2026 was 10.3 kW, maintaining above 10 kW for three consecutive quarters. This trend was largely driven by the desire for greater energy independence, the integration of electric vehicles (EVs), and the general electrification of homes. However, the June figures suggest a temporary recalibration in response to policy adjustments.
June 2026 Solar Installation Trends
According to SunWiz’s analysis of Small-scale Technology Certificate (STC) market data, national registrations for June 2026 eased for the second consecutive month, reaching 322 MW. This figure represents a 4% month-on-month decrease and is 26% below April’s all-time STC record of 435 MW.
While the national average system size declined, not all states followed suit. Queensland, for example, saw a 16% month-on-month increase in STC registrations for June, indicating strong continued uptake of solar in the sunshine state. In contrast, most other states experienced downward trends, with Victoria and South Australia both seeing a 9% decrease in STCs.
“The national average system size slipped to 10.01 kW — a 12-month low — down from May’s 10.47 kW and April’s peak of 11.32 kW,” SunWiz stated in its recent findings.
The Impact of Battery Rebate Changes
The primary driver behind the shift in solar system sizing appears to be the May 1, 2026, adjustments to the federal government’s Cheaper Home Batteries Program. The Clean Energy Regulator confirmed that these reforms altered how STCs are generated for eligible battery installations, including a tiered system based on battery size. These changes were designed to ensure the discount for battery systems remained appropriate across various sizes, with an expectation of “smaller average sizes” for batteries post-reform.
Given the increasing synergy between rooftop solar and home battery storage, a reduction in the financial incentive for larger batteries can indirectly influence the sizing decisions for new solar PV installations. Homeowners might be optimising their solar system size to match a potentially smaller, more cost-effective battery, or simply delaying larger investments until they reassess the new rebate landscape.
What This Means for Australian Homeowners
For Australians considering a new solar installation or an upgrade, this data highlights the dynamic nature of energy incentives and market trends. While the average system size has dipped, the long-term trend towards larger systems for energy independence and future needs, such as EV charging and full home electrification, remains strong.
It is crucial for prospective solar owners to accurately assess their current and anticipated electricity consumption. Tools and expert advice can help determine the optimal system size that maximises savings and future-proofs the home. For more detailed guidance, consider reviewing our article: What Solar System Size Do You Really Need in Australia 2026? Future-Proofing for EVs & Electrification.
Despite the recent dip, the overall outlook for Australian rooftop solar remains robust. SunWiz noted that the June dip represents a “maturing normalisation, not a reversal,” with June 2026 still marking the strongest June on record for solar installations. The cumulative installations from January to June 2026 are approximately 41% ahead of the same period in 2025.
Integrating solar with battery storage continues to offer significant benefits, particularly for managing peak electricity charges. Explore options for Home Battery Backup for Blackouts in 2026: Systems & Costs from $7,000 and learn how to Slash Your 2026 Peak Electricity Charges by Up To 70%: Your Daily ToU Tariff Playbook.
Recent Average Solar System Sizes in Australia
| Metric | June 2026 | May 2026 | April 2026 | Q1 2026 |
|---|---|---|---|---|
| National Average System Size | 10.01 kW | 10.47 kW | 11.32 kW | 10.3 kW |
The market’s response to policy changes underscores the importance of staying informed about the latest incentives and technological advancements to make the most informed decision for your energy future.