Solar care
How to clean solar panels on your roof in Melbourne, from the ground
To clean solar panels on a roof in Melbourne, stay on the ground: rinse them with a gentle garden hose on a cool morning and, on a single-storey home, loosen stuck dirt with a soft, long-handled broom. Never use a pressure washer. Panels tilted at 15° or more generally need no cleaning, Canadian Solar says, because rain does it, and it rains on about 89 days a year here.
Clean when you see dirt or your app shows a drop on clear days, and never climb onto the roof. What you can’t reach is for the rain, a professional or your installer’s service every 2 years: see our solar services.
Updated
Do solar panels in Melbourne need cleaning at all?
Solar Victoria says panels are “designed for outdoor conditions and can tolerate some grime”, though “a build-up of dust, dirt and debris can block light and reduce their efficiency”. The angle decides most of it: Canadian Solar’s Australian manual says panels tilted at 15° or more generally may not need cleaning, and REC’s says “‘Normal’ rainfall will naturally clean the panels if installed at a sufficient angle”. Melbourne averages 88.6 rain days a year, but the fewest when panels work hardest:
| Season | Months | Rain days | Share of a year’s solar |
|---|---|---|---|
| Summer | December to February | 15.3 | 33% |
| Autumn | March to May | 21.2 | 22% |
| Winter | June to August | 26.9 | 16% |
| Spring | September to November | 25.2 | 29% |
Summer averages 15.3 rain days against 26.9 in winter (February has the fewest, 3.6), yet makes 33% of a year’s solar. Panels that do need help:
- Flat or shallow panels. Solar Victoria: “Rain can pool on a flat panel and leave a muddy mark.”
- Bird droppings, which shade part of a cell and don’t rinse off easily (see below).
- Trees overhead: leaves, seeds and pollen, all on Canadian Solar’s list.
- Dusty spots, such as a busy road or building work next door.
How much dirt costs, and when cleaning is worth it
Neither Solar Victoria nor the makers say how much output Melbourne roofs lose to dirt. An even film of dust takes a little off every panel; patchy dirt over part of a cell, like a bird dropping or a line of lichen, matters more. Canadian Solar warns that shaded cells mean “power loss, reduced yield and can cause localized overheating”, and that “Even temporary partial shading will reduce the energy yield.”
What 1% of your output is worth
A 6.6 kW system in Melbourne makes about 9,319 kWh a year (PVGIS model), so each 1% lost is about 93 kWh. Used at home, that is worth about $24 to $30 a year at the Victorian Default Offer’s flat rates (25.96 to 31.98 cents a kWh, by network). Exported, it earns only your retailer’s feed-in tariff, which has had no Victorian minimum since 1 July 2025.
So pay for a clean when dirt is heavy or patchy and your app shows a real drop; for light dust, a rinse or the next rain usually does the job.
How often should solar panels be cleaned?
Neither Solar Victoria nor the makers set a cleaning interval. REC says to “clean the panels when dirt can clearly be seen on the glass surface”; Solar Victoria’s schedule is for the service: at least every 2 years, by a licensed A-Grade electrician, preferably accredited by Solar Accreditation Australia. In practice:
- Monthly: compare clear days in your monitoring app.
- End of summer: look at the panels from the ground (binoculars help).
- Every 2 years: ask your installer to clean them at the service, as Solar Victoria suggests.
- Flat or under 15°: expect to rinse them more often.
How to clean solar panels on a roof from the ground
Solar Victoria’s first rule is “Keep your feet on the ground”. WorkSafe Victoria calls falls construction’s number 1 cause of fatalities, and its first step against them is to work on the ground. Its ladder guidance warns: “Anyone on a ladder is at risk of falling, even at heights below 2 metres.”
Look, don’t touch. Canadian Solar warns that “The voltage and current present in an array during daylight hours are sufficient to cause a lethal electrical shock.” Cracked panels leak current, more so when wet: if you see cracks, scorch marks or loose cables, call a licensed electrician instead.
- Pick a cool, still morning. REC warns that cleaning hot panels risks breakage through thermal shock.
- Look first for cracks, chips, scorch marks and hanging cables.
- Rinse gently with a garden hose, never a pressure washer: Solar Victoria says it could damage them. Keep the spray off the inverter, isolators and cable entries.
- Loosen stuck dirt while it’s wet, with a long-handled, soft-bristled broom on a single-storey home. Canadian Solar asks for non-conductive brushes, so no metal pole, and never rub dirt off dry: it scratches the glass.
- Rinse again with plenty of water, as REC says, and let the panels dry.
- Check your app on the next clear day (below).
Two storeys or a steep roof? Leave it to the rain or a professional, who should not stand on or place anything on top of the panels (Solar Victoria).
What never to use: the makers’ warranty conditions
Solar Victoria says cleaners should not use harsh soap or chemicals: “usually water is enough”. The makers’ installation manuals go further, and a warranty claim is judged against them. Two makers from the panels we compare:
| Canadian Solar | REC | |
|---|---|---|
| When | The cool part of the day, never the hottest hours | When panels are cool, such as early morning (thermal shock) |
| Water and tools | Water low in minerals, pH 6 to 8; a soft sponge, cloth or non-conductive soft brush | Deionised water (rainwater or tap water as a second choice); a sponge, microfibre cloth or soft brush; rinse well |
| Stubborn dirt | For grease, only a cleaning agent it has authorised | Mild biodegradable washing-up liquid; for stains, isopropyl alcohol under 10% |
| Never | Rubbing dirt off dry (micro-scratches); abrasive cleaners or de-greasers; corrosives such as hydrofluoric acid, alkali, acetone or industrial alcohol; any unapproved chemical | High-pressure hoses or cleaners; acidic or alkaline detergents; leaning, standing or resting buckets on panels |
| Warranty | Cleaning damage voids it, as does a hot spot from poor maintenance | Ignoring the manual may count as improper use and invalidate it |
A bottled solar panel cleaning solution isn’t needed for ordinary dirt. Other makers have their own manuals: check yours. Hiring a cleaner? “Check your warranty to make sure that any work done by a cleaning service won’t void it.”
Bird droppings, lichen and pigeons
Bird droppings
Canadian Solar singles out bird droppings as shading to avoid. Soak one with a gentle hose, wait a few minutes, then wipe it with a soft sponge or brush on a long, non-conductive handle. Never scrape it off dry.
Lichen and moss
Lichen grips the glass and frame, so a rinse won’t move it. Soak it and brush gently. Skip moss killers, bleach, vinegar and scrapers: the makers rule out acidic, alkaline, corrosive and unapproved chemicals. What won’t lift is a job for a professional.
Pigeons under the panels
Pigeons nest in the gap under panels, where nests and droppings pile up around the DC cabling, so don’t reach under. Energy Safe Victoria counts clearing debris from under the panels as part of a service. Bird-proofing mesh is roof work for a professional, and should clip on, not be drilled: REC says “The product warranty will be voided if additional holes are made in the frame.”
When to call someone, and checking the result in your app
- A professional cleaner, who should use full safety gear, when panels are very dirty or hard to reach (Solar Victoria). Energy Safe Victoria warns that “solar cleaners” may be cheaper than an electrician, but “the work they do to your system could be creating risks or void your warranty”.
- A licensed electrician for cracked or scorched panels, error codes, a burning smell or unusual noises, or output that stays low after a clean: solar repairs.
- Your installer at the service every 2 years: ask for a clean on the same visit.
Check the result in your app
Compare daily kWh on clear days before and after, as output swings with the season: the PVGIS model has a 6.6 kW system averaging 34.9 kWh a day in January but 14.4 in June. Inverter makers have their own apps, for example Sungrow’s iSolarCloud, Fronius’s Solar.web and Alpha ESS’s AlphaESS app. If a clean makes no difference, the cause is more likely shade or a fault than dirt.
We service, inspect and repair home solar systems across Melbourne. We don’t list panel cleaning as a service yet, so ask about it when you book a service or a repair.
Cleaning solar panels: your questions
How often should solar panels be cleaned?
There’s no set interval. REC’s manual says to clean when you can clearly see dirt on the glass, and Canadian Solar’s says panels tilted at 15° or more generally may not need cleaning, because rain does it. In Melbourne, look at them from the ground after summer, watch your app for a drop on clear days, and ask about a clean at the service every 2 years. What a solar service covers
What is the best way to clean solar panels on a roof?
From the ground, on a cool morning. Rinse the panels with a gentle garden hose, never a pressure washer, and on a single-storey home loosen stuck dirt with a long-handled, soft-bristled broom with a non-conductive handle. Don’t rub dirt off dry, and keep water off the inverter and isolators. If you’d have to climb, leave it to the rain or a professional.
What cleaning solution is safe for solar panels?
Plain water, in most cases: Solar Victoria says usually water is enough. REC allows a mild, biodegradable washing-up liquid and, for stains, isopropyl alcohol under 10%, but no acidic or alkaline detergent. Canadian Solar asks for water low in minerals with a pH of 6 to 8, and allows only cleaning agents it has authorised.
How do you get bird droppings off solar panels?
Soften them first. Wet the dropping with a gentle hose, let it soak for a few minutes, then wipe it with a soft sponge or brush on a long, non-conductive handle. Never scrape it off dry: that micro-scratches the glass. Canadian Solar names bird droppings as shading to avoid, because shaded cells lose power and can overheat.
How do you remove lichen from solar panels?
Soak it with water and work it gently with a soft brush; what won’t lift is a job for a professional using a method your panel maker approves. Skip moss killers, bleach, vinegar and scrapers: REC rules out acidic and alkaline detergents, and Canadian Solar rules out corrosive or unapproved chemicals and scraping dirt off dry.
Cleaning panels in Melbourne: what the rain won’t do
For a Melbourne roof, cleaning is mostly a question of timing. In an average year the Bureau of Meteorology counts 89 rain days at Melbourne (Olympic Park), but only 15.3 in summer, the season that makes 33% of a year’s solar, so dirt builds up just when the panels make the most. Rain also leaves bird droppings, lichen and nests behind. Look from the ground in late February or March, and set a clear day in your app against the 34.9 kWh a day PVGIS models for a 6.6 kW system in January. Each 1% lost is worth about $24 to $30 a year at the Victorian Default Offer’s flat rates, so a light film can wait for the autumn rain. A big drop that a rinse from the ground doesn’t fix points to shade or a fault: a job for a licensed electrician.
Panels clean but output still low?
Tell us what your monitoring app shows and we’ll book a check of the system. Repairs are quoted before any work starts.
Ask us about your solar panels
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Mount Waverley, VIC 3149