Emit Solar | Home Solar Panels | Easy Ownership
Malaysia gets plenty of rain, and most solar panels are installed at an angle that allows water to run off the surface. For most homes, that is enough to clear everyday dust and light dirt naturally.
So, before you pay someone to clean your panels – or think about getting onto the roof yourself – it is worth asking a different question:
Do they need cleaning at all?
THE SHORT ANSWER
Generally, no.
We get a lot of rain. Above about 10° of roof tilt, it washes the panels for you. Dust lowers generation by well under one percent – and going up to recover a small amount of lost output carries risks of its own.
01 · The Rain
The rain already does most of the work
Panels are never flat. Above about 10° of tilt, water runs off instead of pooling on them. And with Malaysian rainfall, that happens often enough to keep them clean.
HOW OFTEN IT RAINS HERE
12 days
of rain in June – the driest month
25 days
of rain in November, the wettest
2,529 mm
of rainfall a year, on average
The Australian Government’s solar maintenance guidance reinforces the point:
“Most panels are installed on a slope of at least 10 degrees, so they should self-clean when it rains.”
[Source: Australian Government, Department of Climate Change, Energy, the Environment and Water]
We see this regularly across our own installations. Dirt marks and bird droppings that are visible one day are usually gone after the next downpour.
WHAT DIRT IS ACTUALLY WORTH
A few kWh/mth
What everyday dust costs you
A University of Wollongong study ran six identical 20kWp systems side by side for 12 months on cleaning schedules from monthly to never and found no discernible difference in yield between them.
So, a little visible dust does not automatically mean your system is losing meaningful amounts of energy.
RM1–RM3
What that is worth per month
Based on typical dust losses on an average residential system.
New technology panels also reduce the impact
The ABC panels we install are designed to reduce the impact of small areas of shading or obstruction. So even if there is a small spot or a bird dropping on part of the panel, the system keeps generating. On older designs, that same spot may have a bigger effect.
02 · The Risk
Know what you risk to get that back
Before anyone goes on your roof, weigh a few Ringgit against these:
Roof damage is the biggest risk
In our experience, it is the most common result of unnecessary roof access and one that can lead to much bigger headaches with water leaks.
Working at height
The fall risk does not become smaller because the job is small.
Cracked tiles
Concrete and clay tiles are not made to be walked on. Some can crack underfoot.
Leaks from nudged tiles
A tile knocked out of alignment can let water in and the leak may only show up weeks later.
Damaged panels or connections
Knocked frames, scratched glass or disturbed electrical connection cost far more than dirt does.
So make the trade consciously.
A small amount of lost generation until the next rain, against a cracked tile, leak or damaged system.
03 · The Exceptions
When cleaning is worth it
Rain is not always enough. Consider cleaning if:
- You are in a very dusty area. Persistent dust, long dry spells, no rain to clear it.
- Your roof pitch is under 10°. Flatter panels do not shed water and dust as easily.
- There is visible buildup. For example, debris, leaves or bird droppings that never wash away even after rain.
- Generation dropped for no obvious reason. A significant, sustained drop in generation nothing else explains is worth investigating.
But even then, do not assume cleaning is the answer. A drop in generation could also come from shading, an inverter issue, a tripped breaker, a connection problem or another system fault. Cleaning fixes none of those.
04 · Check Before You Clean
Start with the system, not the roof
If your solar generation looks unusually low, check the cause.
Solar production naturally changes with cloud cover, rainfall and the amount of sunlight reaching your roof. But if there is a significant and sustained drop that cannot easily be explained, speak to your installer.
If you are an Emit Solar customer, reach out to us first. We can check your system performance and help identify whether the issue is likely to be dirt, shading or something within the solar system itself.
You may find that cleaning is not actually needed.
05 · If Cleaning Is Actually Needed
Get it done safely
We do not recommend climbing onto your roof and cleaning the panels yourself. While cleaning itself may seem simple, getting safely to the panels is not.
If cleaning is genuinely required, use someone with the right equipment and experience working safely at height.
The aim is simple:
Remove the dirt without damaging the panels, roof or electrical installation.
A professional should also know how to clean the panels without using methods or materials that could damage the glass, seals, cabling or surrounding roof.
06 · Hard Rules
Never do this
Any one of these can turn a cleaning job into a repair bill.
No high-pressure washing
Pressure can shift roof tiles and damage sealants.
Not in the midday sun
Panels reach 70°C. Sudden change in temperature is not good for hot glass and can cause it to crack.
Never walk on the panels
It can cause micro-cracks in the cells that you cannot see or undo.
No hard brushes or strong chemicals
Anything not made for panels can damage the protective glass.
Do not interfere with the solar cabling
DC cables and connectors can remain electrically live during daylight hours. They should not be disconnected or disturbed as part of cleaning.
The Bottom Line
- For most Malaysian homes, solar panels do not need regular cleaning. Rain and the natural tilt of the panels usually take care of everyday dust.
- If your panels look dirty but your generation is normal, there may be nothing to worry about.
- If generation drops significantly and stays low, check the cause before you clean. It could be dirt, but it could also be shading, an inverter issue or something else in the system.
- And if cleaning really is needed, get it done professionally rather than climbing onto the roof yourself.
Emit Solar customer?
If something does not look right with your solar generation, contact us for assistance. We’ll review your system’s performance and take it from there.
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