Across Australian rooftops, a quiet renewable energy revolution has been gathering pace. Australia’s Energy Market Operator described the last three months of last year as a “landmark moment”, with renewables’ energy share rising above 50% for the first time.

Australia has for many years had the highest penetration of household solar panels in the world, with about 4.3m homes – roughly one in three – having installed rooftop solar, with a capacity exceeding 28GW.

But as more households embrace renewable power, a recent University of New South Wales study has found solar panels are also failing faster than expected. This raises questions about what to look for when shopping for solar for your home or business, and how best to maintain panels in increasingly volatile and extreme weather conditions.

Like most manufactured products, solar panels will degrade over time. But when a team from the UNSW school of photovoltaic and renewable energy engineering analysed 11,000 photovoltaic samples, they concluded that around one in five performed 1.5 times worse than expected.

This implies that instead of the 25-year expected lifespan, 20% of panels will start to fail after just 12 years. Key problems identified include internal failures due to panel elements interacting with each other, poor quality control resulting in manufacturing defects, and other flaws that result in performance loss over time.

“For the entire dataset, we observed that system performance typically declines by around 0.9% per year. However, our findings show extreme degradation rates in some of the systems,” said Yang Tang, one of the research authors, in a press statement last month. “This means that for some systems … they could lose about 45% of their output by the 25-year mark.”

Everyone’s experience with solar panels will differ, but simple home maintenance strategies can increase their longevity. Tim Forcey, the author of My Efficient Electric Home Handbook, had solar panels installed in his Melbourne bayside home in 2008 and says while he kept them as “a bit of a science experiment”, they are still working. He added 22 more panels in 2017 that now provide all his home’s electricity needs.

Forcey says during a wild hailstorm last year that destroyed a sheet of plastic over his patio, the solar panels survived. He says one simple tip is to install the panels at an angle so they don’t accumulate and hold too much water and mud. “I keep them clean with a brush on a long stick, especially taking care to get rid of any moss and lichen that accumulates.”

How to install your panels right from the start

Brendan Lang, an electrician and founder of Get Off Gas, says there are three important things that people can do to minimise the risks of their panels not meeting expectations: using quality products from the start, getting expert local installers on board and regular maintenance.

“You wouldn’t expect your motor vehicle to be running perfectly after 25 years if you didn’t service it – same goes for renewable energy.” Lang recommends having a qualified expert guide you through the installation process and come back to service your panels every two to three years.

“Systems come in many varieties of quality and therefore serviceability and longevity. Good maintenance is vital for safety as well as efficiency and longevity. Keeping your panels clean, cabling and connections in check, and ensuring the racking affixing the panels to your roof is fastened are all equally important,” Lang says.

The other advantage of regular servicing is that it will allow you to monitor your panels’ performance. If the performance markedly drops, you can make a claim under warranty (usually 25 years on quality panels).

When things go wrong: repair or recycle?

All solar panels have a limited lifespan, but there are many factors to take into account when considering whether to repair or replace your existing unit.

If only one of your solar panels fails, you may be able to find a suitable replacement, advises Finn Peacock of Solar Quotes, but it must have very similar physical size and specifications to be suitable. If it’s a problem with your inverter, secondhand inverters are widely available, and a good installer can replace it for you.

“A good original installer will install one type of panel and likely keep spares or be able to get them from the manufacturer,” Peacock says. “As a last resort, you may be able to just remove the panel, or bypass it electrically – depending on the string configuration. You’ll lose one panel worth of energy (about 2kWh per day) but keep the rest of the system going for minimal cost.”

If your system is more than about six years old, replacing the whole array will get you much more efficient panels, producing more energy, and you may be able to claim the solar panel rebate again, Peacock says.

If you do need to replace your panels, make sure you get them properly recycled.

“Don’t assume the people removing them will recycle them – because it costs $30 per panel to do it, they unfortunately often end up elsewhere,” he says. “You need to insist on it and ask for the receipt.”

Peacock says simple things like avoiding permanent shade, regular servicing and ensuring leaves don’t build up underneath will give your panels the best chance of longevity.