For solar panels to operate at maximum efficiency, keeping them clean is essential. Solar panels convert sunlight directly into electricity, so any shadows or dirt blocking sunlight can compromise power output. Many homeowners are now opting to install solar, drawn in by financial incentives, environmental benefits, and independence from the power grid. But making the most out of your solar investment requires properly maintaining your panels. Learning best practices for solar panel cleaning is critical.
How Dirt and Dust Impact Efficiency
Outdoor exposure means solar panels interact with all types of dirt, dust, pollution, and other grime. As these particles accumulate, they can smear across the glass surface, blocking sunlight from the photovoltaic cells underneath that convert light to electricity. Studies show dust and dirt buildup can degrade solar output by up to 50% in extreme cases. Keeping panels pristine boosts energy production and return on your solar investment.
Cleaning Frequency Recommendations
Most solar panel manufacturers recommend thoroughly cleaning panels at least 2-4 times per year. But frequency depends on environmental factors that impact dirt buildup in your area. Homes near roads, industrial areas, or agricultural land may need more frequent cleaning than rural or suburban locations. Visually inspect panels seasonally to gauge if cleaning is warranted sooner.
It’s also ideal to clean panels after any substantial accumulation of dust from seasonal wind storms or other particle events that noticeably lower output. Use solar monitoring software if available to track daily power generation trends. Any sustained production dips likely indicate a need for cleaning.
Solar Panel Cleaning Methods
Cleaning solar panels does not require specialized products or excessive time if done properly and safely. Here are some general guidelines:
Since most residential solar panels are installed on rooftops, caution is vital anytime you access or handle panels. Use a sturdy ladder secured at a safe angle. Wear protective eye gear, long sleeves and pants. Clean solar panels early or late in the day when temperatures are cooler to avoid overheating. Never step directly on panels as this risks damage, compromising safety as well as performance. Mobilize any necessary tools with tethers or tool belts to prevent dropping items. Don’t spray water over electrical conduits or onto the roof surface, only onto panel glass. Turn off the inverter and isolate panels from other system components before spraying water if required for heavy soiling. Exercise extreme care when working around solar equipment and at roof elevation at all times.
Start With Dry Clearing
For light surface dust or accumulated organic matter like leaves, begin clearing debris using a soft brush or broom specifically for solar panels. Avoid abrasive brushes that could potentially scratch panel surfaces. Gently sweep dry debris off panels and housings without applying any liquids for routine maintenance cleaning. This simple clearing often restores output noticeably without extensive effort.
If excess grime remains that is visibly blocking solar absorption, follow up dry brushing with a spray cleanse. Use demineralized or distilled water to avoid mineral spotting. Add at most only a few drops of gentle dish detergent like original Dawn formula into spray bottles with water. Apply cleaning solution then lightly agitate with a microfiber solar cleaning mop to lift stubborn dirt. Rinse panels thoroughly with spray solution afterward so no debris or cleaning agents remain. Let panels fully dry before reconnecting system components if isolated. Avoid placing any pressure directly on panel surfaces when wiping or rinsing. Work in cooler shaded conditions whenever possible.
DIY Vs Professional Cleaning
While most homeowners can safely clean smaller rooftop solar arrays 2-4 times per year with some effort, professional solar panel cleaning may provide benefits for larger commercial scale systems or extremely dirty panels requiring chemical cleaners. Commercial crews use specialized equipment like cherry pickers for safe access to panels on complexes or multifamily buildings as well as industrial power generation facilities. They also have experience handling any electrical isolation procedures panels may require before wet cleaning.
Professionals have access to heavy duty chemical cleaners for severely soiled panels that often plague agricultural and industrial sites. They use high pressure rinses or ultrasonics combined with cleaning agents to restore heavily degraded output. After assessing your specific solar array and environment, determine if large-scale professional washing at least once per year could boost your system’s overall performance and ROI. Some solar companies offer periodic cleaning services or maintenance packages.
Avoiding Future Soiling
Preventing solar panel fouling through proactive steps beyond just periodic washing is also wise for long term efficiency. Consider adding panel canopies or raised mounting legs in dusty locales to avoid ground debris. Prune overhanging tree branches that could increase shading or dropped leaves/debris onto panels. Install panels at angles facilitating self-cleaning from rainfall whenever feasible. Water beading and sheeting helps carry away dry particles before they accumulate. Just don’t rely solely on rainwater to keep panels clean.
Make Solar Panel Care Part of Routine Property Maintenance
With solar energy tax credits, clean power incentives, and rising electricity rates making residential solar more financially viable than ever, properly maintaining panels protects your investment in renewable energy. Schedule periodic solar panel inspections and cleaning sessions around seasonal changes just like you would gutter or air conditioning maintenance. Keeping panels consistently clean, clear, and output optimized ensures you reap the most from your solar system for years to come.
Eng. Matthew Joseph Nandirio is the Founder of walkingsolar.
After graduating from the University of Houston in 2002, matt started working as a Solar Electrical Engineer for several multi-national solar energy companies.
He has a wide range of experiences including solar system requirement analysis, planning, maintaining, debugging and even solar device development through research.
He now shares his 20 years of expertise through his articles on the walkingsolar website.
Further, he is also the author of two books on Solar Technology, “Solar Power for Villages” and “DIY Solar System for Dummies”.