Every modern solar panel system comes with a monitoring app that shows how much electricity your panels are producing. And most landed homeowners probably check it keenly for the first fortnight, then never again.
Out of sight, out of mind, right?
With the roof being out of your sight, and the assumption that the rain will do all the work in keeping the solar panels clean, it’s easy to overlook the cleanliness of it. But as much as the rain helps, it does not finish the job. Dust, pollen, tree sap, and the occasional bird all settle on the glass and chip away at output.
12 to 18 months or more frequently, how often you need to clean your solar panels comes down to how much of that your roof collects.
Believe it or not, Singapore does not have a dust problem the way drier countries do. Our soiling is stickier and more organic, and it comes from a few main sources:
Our roughly 167 rainy days a year wash the light stuff off. The stubborn material, sap and droppings baked on by the heat need a proper clean.
How often solar panels need to be cleaned then depends on your roof and what is present around it:
Of course, you do not need to climb onto your roof to know when to clean solar panels. The signs are visible from the ground and from your phone:
Of everything that ends up on a panel, bird droppings do the most damage.
Dust spreads thinly, so a panel loses a little light everywhere. A dropping does the opposite.
It sits as a thick, opaque blob and blocks sunlight from the solar cells beneath it completely. Those solar cells, the small squares across the panel, are wired together in a chain called a series. Because current runs through the whole chain, one heavily shaded solar cell can cut a panel’s output by 20 to 30% and drag down the panels wired to it.
Left there, it worsens.
The shaded cell heats into a hotspot, which over time causes permanent damage, and in bad cases harms the junction box, the sealed unit on the panel’s back where the wiring connects. Singapore’s heat bakes droppings onto the glass within days, making them harder to remove and more likely to stain for good.
Some neighbourhoods get it worse. The leafier landed districts, Bukit Timah, Holland, Tanglin, and stretches of the East Coast, come with mature trees, and mature trees come with birds that treat your roof as a hangout spot.
So can you clean the panels yourself?
If they sit on a low single-storey extension you can reach safely from the ground, a quick rinse is fine. For most landed homes, though, the panels are on a pitched upper roof, and reaching them safely means harnesses, scaffolding, and training to work at height. However, going up with a garden hose and a ladder is how a Saturday chore turns into an A&E visit.
Access is only half the risk, though. The wrong brush or cleaning agent can scratch the anti-reflective coating, damage the junction box seals, or void the warranty. For panels within safe reach, a few rules keep both the solar panels intact:
For anything you cannot reach safely from the ground, hand it over. When to call one in, and what to expect:
Cleaning keeps the glass clear, but only handles what sits on the surface. The faults that eat into output over the years are the ones you cannot see from the driveway, and an annual inspection is the only thing that can catch them. A quality residential solar panel installation reduces how often those faults appear, but never removes the need for a check.
A full inspection covers:
Solar panels do require maintenance beyond a wash, and many solar panel warranties make it a condition: documented proof of regular solar panel maintenance is often what keeps the coverage valid.
The inspection pays closest attention to the inverter. It converts DC electricity from your panels into the AC power your home runs on, and it works harder than any other component in the system, which is why it wears out first.
Panels tend to run for 25 to 30 years, but a typical string inverter manages 10 to 15 years, meaning at least one replacement over the system’s life is expected. That is not a fault. It is just how the component ages.
The warning signs that an inverter is nearing the end are usually clear:
Replacing an inverter in Singapore costs roughly the following, scaling with system size:
A replacement is also the right time to upgrade to a hybrid inverter, if you might add battery storage later.
Skip all of this for long enough and the cost surfaces where a homeowner notices: the output.
A well-maintained system sustains around 90 to 95% of its original output across 30 years. A neglected one, worn down by soiling and faults nobody caught, can slide down to 75 to 80%.
Put that in money. On a 15 kWp system generating in the region of S$5,500 a year, a 15% shortfall is roughly S$800 a year, depending on usage, tariffs, and system size. Over a decade, that is more than S$8,000 left on the roof.
Against the cost of avoiding it, the comparison is not close:
A documented maintenance history also strengthens a warranty claim and can contribute to long-term home value.
Keeping a system at its best comes down to staying ahead of it: clearing the panels before soiling costs you output, and before an undetected fault in a component eats into your output for months. Our solar panel maintenance services cover exactly that, from professional cleaning and full system inspection to inverter diagnostics and performance reporting for landed homes across Singapore, whether your residential solar panel installation was handled by us or another company.
For homeowners on a FOMO Energy solar panel system, our REConnect programme goes further, letting you trade the Renewable Energy Certificates your panels generate for O&M services, 24/7 fault monitoring, and extended warranties.
If your solar panels have been up for a year or more without a proper look, an inspection is the place to start. It tells you what the system is producing against what it should be, and whether it needs a clean, a repair, or nothing at all.
