Sunprint
The short answer
Most Florida homeowners never need to clean their solar panels. Rain washes off ordinary dust, and the National Renewable Energy Laboratory's soiling map, built from measured performance at 255 U.S. sites, shows all three Florida sites losing less than 1 percent of their yearly energy to dirt, including an array lying flat in Brevard County. By contrast, 128 of 137 California sites lost more than 1 percent.
Check your panels from the ground a few times a year, especially after the dry spring. Clean them, gently and from the ground if you can, when you can see dirt, bird droppings, leaves or a band of grime along the bottom edge. Never use a pressure washer, and don't climb onto the roof.
Rain does the work, except in a dry spring
Both panel makers whose instructions we checked count on rain. REC says its panels are made so that "normal and regular levels of rainfall will clean them naturally if installed at a sufficient angle." Canadian Solar says panels "with sufficient tilt (at least 15°), generally may not require cleaning (rain will have a self-cleaning effect)." For reference, a 4/12 roof pitch is about 18 degrees and a 6/12 pitch about 27.
Rainy days by month in five Florida cities
Average days a month with at least 0.1 inch of rain. Bigger circle, more rainy days; orange marks months with fewer than five.
Sources: NOAA NCEI U.S. climate normals, 1991 to 2020 (airport stations); UF/IFAS on the pollen season.
The catch is timing. In Orlando, Tampa and Miami, November through April average only about 2 to 5 rainy days a month, and that dry stretch overlaps the tree pollen season, which UF/IFAS puts at January to June in Florida. Pines and oaks release pollen in huge volumes to travel on the wind, so a yellow film on the panels in spring is likely pollen. The summer rainy season, with about 8 to 13 rainy days a month from June through September in those cities, usually rinses it away. Pensacola's rain is spread more evenly through the year.
What dirties Florida panels
A thin, even film of dust costs a little everywhere. A spot that covers part of a cell, like a dropping or a leaf, can cost far more than its size, because the cells in a panel are wired together.
- Pollen and dust. An even film builds up in the dry months and usually washes off in summer storms.
- Bird droppings. They sit on individual cells. REC notes that sites with heavy bird activity may need cleaning more often "to reduce shading of panels caused by bird defecation."
- Leaves, seeds and sap. Canadian Solar lists bird droppings, seeds, pollen, leaves and branches among the things to keep panels clear of, and warns that shading from "dirt or debris (e.g., plants, bird droppings, etc.)" should be avoided because shaded cells lose power and can overheat.
- Mold, algae and fungi. In humid climates, a living film can grow on the glass. In a study in São Paulo, Brazil, panels left outdoors gathered dust plus a film of fungi, algae and bacteria, and lost 7 percent of their power within 6 months and 11 percent by 18 months. REC notes growth can appear on the back of panels too and calls that "not generally a cause for concern."
- Roof-algae treatments. The asphalt roofing industry's own advice for lightening dark algae streaks on shingles is a solution of household bleach, and bleach is corrosive. Panel makers bar corrosive, acid or alkali cleaners, so keep roof treatments off the panels.
The band of grime along the bottom edge
On framed panels, the aluminum frame stands about 1 to 3 millimeters above the glass. Light rain and morning dew wash dirt down the panel, but not over that lip, so dirt collects in a band along the lowest edge, and it's worst at low tilt angles. Researchers who surveyed this edge soiling found it even in a Chinese city with about 71 inches of rain a year, and cite a case where grime covering just 0.5 percent of a panel, over parts of two cells, cut its peak output 9 percent.
If you see a dark line along the bottom of your panels, it's worth a gentle cleaning even if the rest of the glass looks fine. Low-slope roofs, porch roofs, carports and ground mounts tilted under 15 degrees are the most likely to need it.
How to clean solar panels safely
These steps combine REC's cleaning guide and Canadian Solar's installation manual. Your own panels' manual comes first, since the two makers differ on details such as which cleaning agents are allowed.
- Look first. Inspect from the ground for cracked glass or loose wiring. Canadian Solar warns that cracked panels are a shock hazard, worse when wet, and says to disconnect the system before cleaning; your system's manual shows how to shut it down. If anything looks damaged, don't clean it.
- Pick a cool time. Clean early in the morning or late in the day. REC says working panels run about 20°C (36°F) above the air temperature, and cool water on hot glass can crack it.
- Rinse from the ground. REC allows a standard garden hose at normal household water pressure. Soft or low-mineral water is best; Canadian Solar asks for near-neutral water at no more than 40 bar, about 580 psi.
- Loosen stubborn spots gently. Use a soft sponge, microfiber cloth or soft non-abrasive brush on an extension pole. Never rub dry dirt; wet it first, since dry scrubbing scratches the glass.
- Soap only if needed. REC allows a mild, biodegradable washing-up liquid, rinsed off right away. Canadian Solar bars de-greasers and a long list of chemicals, including alcohols, so check your manual.
- Let it dry. Air-drying is best; REC also allows a rubber squeegee pulled from the top down.
What to never use on solar panels
Fine, per the makers
- A garden hose at normal household pressure
- Soft sponge, microfiber cloth or soft brush
- Clean water, ideally low in minerals
- Cleaning in the cool part of the day
- Letting the panels air-dry
Off limits
- Pressure washers and steam cleaners
- Knives, blades, metal scrubbers or scraping dry dirt
- Abrasive cleaners, de-greasers, acids, alkalis and bleach-type solutions
- Cold water on hot panels
- Standing, walking or leaning on the panels
Cleaning and your warranty
Cleaning the wrong way can cost you the panel warranty. Canadian Solar's manual says "Damages induced by inappropriate cleaning procedures will void Canadian Solar warranty," and that damage from dry cleaning or from equipment that puts heavy loads on the panel will too. REC says pressure or steam cleaners, high-pressure hoses, knives, blades and metallic sponges "will invalidate the warranty," and that it doesn't warranty any sprays or coatings applied to the glass.
Neglect can matter as well. Canadian Solar says that if a defect such as a hot spot is caused by poor maintenance, including debris left shading the cells, it voids the warranty. So droppings or leaves that sit on the glass for months are worth removing. For what else to check in a panel warranty, see how long solar panels last in Florida.
Is a professional cleaning worth paying for?
For routine dust, usually not in Florida. Take a south-facing 10 kW system on a 6/12 roof in Orlando, which NREL's PVWatts model puts at about 15,250 kWh a year, and value each kWh at Florida's 2025 average home price of 15.24 cents (EIA):
| Yearly loss to dirt | Energy lost | Worth about |
|---|---|---|
| 1% (Florida sites on NREL's map lost less) | 152 kWh | $23 |
| 2% (PVWatts' default assumption) | 305 kWh | $46 |
| 5% (a heavily soiled array) | 762 kWh | $116 |
A commonly cited national range for a professional cleaning is $150 to $500 a visit, or $10 to $20 a panel (HomeGuide). At the losses measured in Florida, one visit costs more than several years of dirt. Paying for a cleaning makes more sense when:
- You can see heavy droppings, leaves or a grime band, and you can't reach it safely from the ground.
- The panels sit at a low tilt, under trees, or near dust from construction or unpaved roads.
- Your monitoring app shows output well below the same month last year with no change in weather or shade.
- Someone is on the roof anyway, for an inspection or other work.
If production drops and the panels look clean, dirt probably isn't the cause; our guide to why a solar bill can still be high covers shade, sizing and silent failures.
Stay off the roof
A solar array is a live electrical system on a sloped surface. Canadian Solar's manual warns that "the voltage and current present in an array during daylight hours are sufficient to cause a lethal electrical shock," and REC says never to stand, walk or lean on panels. The asphalt roofing industry warns that roofs are dangerous to walk, climb or work on and recommends that only trained professionals do it. Clean from the ground with a hose and a pole, and leave anything you can't reach safely to someone trained and equipped to work at heights.
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Common questions
How often do solar panels need to be cleaned in Florida?
Usually not on a schedule. Rain cleans panels tilted 15 degrees or more, and the three Florida sites on NREL's soiling map lost less than 1 percent of their yearly energy to dirt. Look at your panels from the ground a few times a year, especially after the dry, pollen-heavy spring, and clean them when you see dirt, droppings, leaves or a band of grime along the bottom edge.
Does rain clean solar panels?
Mostly, yes. Panel makers design for it: REC says regular rainfall cleans its panels naturally if they're installed at a sufficient angle, and Canadian Solar says panels tilted at least 15 degrees generally may not need cleaning. Rain doesn't reliably remove bird droppings, leaves or the dirt that collects against the bottom frame.
How do you clean algae off solar panels?
Gently, with water and a soft sponge or brush from the ground, in the cool part of the day. If that isn't enough, REC allows a mild biodegradable soap rinsed off right away. Don't use bleach or other corrosive, acid or alkali cleaners; panel makers bar them, and the wrong cleaning method can void the warranty.
Can I pressure wash my solar panels?
No. REC doesn't permit pressure washers, steam cleaners or high-pressure hoses and says using them invalidates its warranty. Canadian Solar caps water pressure at 40 bar, about 580 psi. A garden hose at normal household pressure is fine.
How much does solar panel cleaning cost?
A commonly cited national range is $150 to $500 a visit, or about $10 to $20 per panel, with minimum charges common (HomeGuide). In Florida, where rain keeps most panels clean, routine cleaning rarely pays for itself; it makes sense for heavy spot soiling you can't safely reach.
Does cleaning solar panels void the warranty?
Cleaning the right way doesn't. Cleaning the wrong way can: Canadian Solar says damage from inappropriate cleaning voids its warranty, and REC says pressure or steam cleaners, blades and metal scrubbers invalidate its warranty. Canadian Solar also says hot spots caused by poor maintenance, such as debris left shading cells, void the warranty.
What is the yellow dust on my solar panels in spring?
Most likely pollen. UF/IFAS says Florida trees often release pollen from January to June, and pines and oaks produce it in huge volumes. It coincides with Florida's driest months, so it can build up until the summer rains wash it off.
Is it safe to clean solar panels myself?
From the ground with a hose and a soft brush on a pole, generally yes, if the panels aren't cracked. Don't climb onto the roof or stand on panels: arrays carry enough voltage and current in daylight to cause a lethal shock, according to Canadian Solar, and roofs are dangerous to work on.
Related guides
- How long do solar panels last in Florida?
- Why is my electric bill still high with solar?
- Do solar panels cause roof leaks?
- How much electricity does a solar system produce in Florida?
- Solar panels and hurricanes in Florida
Cleaning steps summarize two manufacturers' published instructions; follow the manual for your own panels. The cost range is a commonly cited national figure, not a quote. Sources: NREL (now NLR), photovoltaic module soiling map and site data · NREL, Availability and Performance Loss Factors for U.S. PV Fleet Systems (2024, PDF) · NREL, PVWatts Version 5 Manual, default system losses (PDF) · NOAA NCEI U.S. climate normals, 1991 to 2020 · UF/IFAS Extension, Urban Trees and Allergies in North Florida · REC, Quick guide to cleaning (PDF) · REC solar panels installation manual (PDF) · Canadian Solar installation manual, U.S. edition 3.3, July 2026 (PDF) · Cui et al., Characterization of Soiling Bands on the Bottom Edges of PV Modules, Frontiers in Energy Research (2021) · Asphalt Roofing Manufacturers Association, Algae Discoloration of Roofs · Stanford Environmental Health and Safety, sodium hypochlorite (bleach) · Shirakawa et al., Microbial colonization affects the efficiency of photovoltaic panels in a tropical environment, Journal of Environmental Management (2015) · U.S. EIA, Form EIA-861M sales and revenue data (2025 Florida average price) · HomeGuide, solar panel cleaning cost (commonly cited range). Reviewed September 2026.
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