Original data analysis · Victoria · 2026
Victoria's ageing rooftop solar fleet.
How much of Victoria's recorded rooftop-solar installation history is now more than a decade old, where those older cohorts are concentrated, and what the numbers can and cannot tell us about systems on roofs today.
30.8% of recorded installation events are in the conservative 10+ year cohort.That is 279,085 events from complete installation years 2015 or earlier, out of 906,682 recorded events in the Victorian 3xxx-postcode dataset.
Four headline findings.
These are recorded installation events, not a census of unique homes or proof that the original equipment is still operating. The age thresholds use complete calendar years so the headline cohorts are lower-bound counts rather than estimates.
Interpretation: the 10+ figure means an installation event was recorded in a complete calendar year that is unambiguously at least ten years before the source date. It does not mean 30.8% of Victorian homes currently have 10+ year-old solar.
Where are the older recorded cohorts concentrated?
The count ranking highlights large installed bases. The share ranking highlights postcodes with an older installation mix. Postcodes can contain multiple suburbs or localities.
Largest 10+ cohort by count
Postcodes with the most recorded installation events from 2015 or earlier.
- 1Postcode 30295,72520.4% of recorded events
- 2Postcode 39775,33426.0% of recorded events
- 3Postcode 30305,14527.1% of recorded events
- 4Postcode 30233,55039.9% of recorded events
- 5Postcode 30643,50816.9% of recorded events
- 6Postcode 38053,35036.0% of recorded events
- 7Postcode 32162,97837.4% of recorded events
- 8Postcode 31502,58432.2% of recorded events
- 9Postcode 38062,56328.7% of recorded events
- 10Postcode 30372,53439.7% of recorded events
Highest 10+ cohort share
Limited to postcodes with at least 1,000 recorded events to reduce small-denominator distortion.
- 1Postcode 321945.0%1,172 older-cohort events
- 2Postcode 357944.3%547 older-cohort events
- 3Postcode 356143.9%496 older-cohort events
- 4Postcode 386043.6%614 older-cohort events
- 5Postcode 390943.4%833 older-cohort events
- 6Postcode 363643.2%580 older-cohort events
- 7Postcode 385142.8%745 older-cohort events
- 8Postcode 302842.1%1,414 older-cohort events
- 9Postcode 319742.0%657 older-cohort events
- 10Postcode 382541.6%1,559 older-cohort events
By raw count, postcode 3029 leads this snapshot with 5,725 recorded events in the conservative 10+ cohort. Among postcodes meeting the minimum-volume rule, postcode 3219 has the highest older-cohort share at 45.0%.
The installation history behind the cohorts.
Victoria's recorded rooftop-solar history was built in waves. This annual series shows the installation-event history behind the age cohorts rather than reducing the story to one percentage.
Recorded solar installation events by year
* provisional source years are lighter2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
Current-year caution: recent installation years are provisional because Small-scale Technology Certificates can be created for up to 12 months after installation. Older cohort counts are less exposed to that lag because they use much earlier installation years.
Why does the 10-year threshold matter in Victoria?
Age is not a failure signal, but ten years is a practical policy and upgrade-planning threshold for some Victorian households.
Solar Victoria's current owner-occupier eligibility rules say a property must not have had a solar PV system installed in the last 10 years, and its guidance says households with a system that is 10+ years old might be eligible to replace or expand it, subject to the rest of the program criteria.
For homeowners, an older installation can also make questions about inverter condition, panel layout, roof space, battery compatibility and backup design more relevant. None of those decisions can be made from postcode age data alone.
Use and cite the data.
Journalists, councils, researchers, community-energy groups and industry writers may quote the derived figures with attribution. Include the source date because the CER files are updated over time.
Suggested citation
Melbourne Solar Guide (2026), Victoria's Ageing Rooftop Solar Fleet: 2026 Data Report. Analysis of Clean Energy Regulator Small-scale installation postcode data, source snapshot through 31 August 2026.
Underlying CER material is used under CC BY 4.0. Melbourne Solar Guide's cohort calculations and limitations are documented on the methodology page.
Method in brief.
The report groups annual CER installation-event totals for installed postcodes 3000 to 3999. It does not estimate installation months inside annual cohorts.
| Published cohort | Complete installation years included | Recorded events | Share of all recorded events |
|---|---|---|---|
| Definitely 10+ years | 2015 or earlier | 279,085 | 30.8% |
| Definitely 12+ years | 2013 or earlier | 207,598 | 22.9% |
| Definitely 15+ years | 2010 or earlier | 47,721 | 5.3% |
Because the source date is 31 August 2026, the next calendar year after each cut-off can contain some installations that already meet the threshold. Those partial-year cases are intentionally excluded rather than estimated from annual totals.
Primary sources.
Australian Government · Clean Energy Regulator
Small-scale installation postcode data ↗
Source installation series used for all cohort counts and rankings. The CER notes that the data includes new installations, upgrades and stand-alone systems, and that recent years can rise during the STC creation period.
Victorian Government · Solar Victoria
Solar panel (PV) rebate eligibility ↗
Current 10-year property eligibility rule and guidance for replacing or expanding an existing 10+ year-old PV system.
CER dataset SHA-256: 9e1f03a959fec5dbcd56692953dfaa9cee4a0b761f8d19da8e5e19fc7bbbd5b5