How to Clean Solar Panels the Right Way [A Detailed Guide]

• By Solartiqo
• June 5, 2025June 5, 2025
• With 0 comments

If you’ve invested in solar panels, whether it’s a small home setup or a large rooftop array, one thing’s certain: keeping them clean matters more than most people think.

We always see a consistent pattern: panels lose efficiency simply because they’re not appropriately cleaned or not cleaned at all.

In this guide, we’ll walk you through why, when, and how to clean your panels, and also share a few things I’ve learned along the way that you won’t find in manufacturer manuals.

 

Why Should You Bother Cleaning Your Solar Panels?

Let’s clear this up: Solar panels don’t clean themselves.

Solar panels don’t have any moving parts; they quietly sit there and convert sunlight into electricity. But the surface of a panel is its most critical component, and anything that blocks sunlight reduces its effectiveness.

Even in areas with regular rainfall, I’ve found natural elements often leave more residue than they remove. Dust, sap, bird droppings, and air pollution create layers that block sunlight. And panels don’t need to be visibly filthy to lose efficiency—a thin, even dust layer can reduce output by 5–15%.

Here’s what happens when panels get dirty:

• Dust creates a thin film that scatters light.
• Bird droppings, unlike dust, are not transparent and can completely block sunlight over a cell.
• Leaves, pollen, or urban grime can accumulate faster than people realize, especially near trees or busy roads.
• Salt deposits from sea breeze can form sticky, corrosive layers over time.

 

Here is how dirt impacts solar performance:

Type of Dirt	Impact on Performance	How It Happens
Dust & Pollen	5–15% loss	From roads, dry winds, local plants
Bird Droppings	Up to 25% loss	Blocks entire cells in string
Salt Residue	Gradual performance drop + corrosion risk	Common in coastal areas
Leaves/Sap	Uneven hot spots + output drop	Tree overhangs and shade
Industrial Residue	Film reduces light absorption	Near factories, construction

 

A panel that isn’t cleaned for a year can easily produce 10–15% less energy. Multiply that by your system size and electricity rate, and you’ll see how much money is slipping away.

When inspecting low-performing systems, poor panel hygiene is among the top 3 causes, right after shading issues and inverter faults.

 

Real Example:

I once audited a 30kW system in a semi-urban area. After cleaning, output improved by 18% overnight. That’s like turning on an extra 5.4kW system — without adding a single panel.

When Should You Clean Solar Panels?

Not all solar systems are equal. A 3kW home system in a leafy suburb won’t need the same cleaning cycle as a 50kW setup near a cement plant. That’s why the “one size fits all” advice just doesn’t work here.

 

Instead, base your cleaning frequency on your environment, panel access, and system size.

Solar Panel Cleaning Guidelines Based on Location:

 

Environment	Suggested Cleaning Cycle	Why?
Urban Areas	6 months	Smog, dust from roads, and occasional bird droppings
Rural/Farm Areas	3 – 4 months	Dust from unpaved roads, pollen, and farm residue
Near Factories/Industrial Zones	3 months	Airborne particles, oily film from machinery
Coastal Areas	3 months	Salt mist can be corrosive
Heavy Tree Cover or Bird Activity	2 – 3 months	Droppings and sap build up quickly
After major storms or fire	As needed	Residue from ash, debris, heavy rain

Quick Tips by Solartiqo:

• Do a quick visual inspection every 4–6 weeks.
• Watch for sudden drops in generation (most systems now have monitoring apps).
• Clean after big storms, sandstorms, or wildfire smoke — these leave residue even if not visible.

Can You Clean Them Yourself? Or Should You Call a Pro?

Whether you clean the panels yourself or hire someone depends on two key things:

• How safe and easy it is to reach your panels
• How dirty they actually are

If your system is ground-mounted or installed on a flat roof, and you just need to deal with light dust, doing it yourself makes sense. But once you’re dealing with height, steep roofs, sticky grime, or big systems, it’s better to get a professional.

DIY Solar Panel Cleaning Makes Sense If:

• Panels are easily accessible, like single-story flat roofs, ground mounts, and carports.
• You’re comfortable working at height (and using ladders safely).
• You’re dealing with light dirt or seasonal cleaning.

You’ll need:

• A soft brush or sponge
• Mild soap (non-abrasive, biodegradable if possible)
• A garden hose with a long nozzle
• Safety gear (non-slip shoes, gloves, and ideally, a harness if on a sloped roof)

Call a Professional Solar Panel Cleaner If:

• The roof is steep, high, or dangerous to climb.
• You have a large system (20+ panels) and limited time.
• There’s tough grime or stains (e.g., dried sap, cement dust from nearby construction).
• You want to protect your warranty — improper cleaning can void some panel warranties.

Solartiqo Advice for Solar Businesses:

If you’re an installer or O&M provider, bundle annual or bi-annual cleaning into your service plan. Clients appreciate not having to think about it, and the panels perform better year-round.

Step-by-Step: How I Recommend Cleaning Solar Panels

Most manuals tell you “use water and a soft cloth,” but here’s the deeper process you shall consider:

1. Shut Down Your System Properly

Before anything touches your panels:

• Switch off the AC inverter.
• Turn off the DC isolators (if accessible).
• For grid-connected systems, this ensures no current is flowing from or to the panels.
• Wait a few minutes before starting.

2. Do a Dry Inspection First

• Look for visible cracks, damaged cables, or nesting around the frame.
• If birds have nested under the panels, call a pest control specialist — don’t remove them yourself.
• Check for loose fasteners or any sign of corrosion on mounts.

3. Use Water to Loosen Dirt

• Use a low-pressure hose, never a high-pressure jet, which can crack the glass or force water into connectors.
• Avoid cold water on hot panels (early morning or evening is ideal).
• Let the water sit for 2–3 minutes to loosen any grime.

4. Apply Mild Soap or Panel Cleaner

• Mix a few drops of mild, non-abrasive soap in a bucket of warm water.
• Use a microfiber cloth, sponge, or water-fed pole with a soft brush head.
• Work in small sections. Rinse thoroughly after so that no residue dries on the surface.

5. Dry or Let Air-Dry

• Panels can air dry naturally, but soft microfiber drying helps avoid water spots.
• Avoid leaving streaks, especially in hard water areas.

What NOT to Do When Cleaning Solar Panels?

Most of you may be aware of how to clean solar panels, but you need to be aware of what to avoid so that there are no aftershocks or costs associated with maintaining your solar panels.

• Don’t use pressure washers (they can loosen seals).
• Don’t use hard brushes or metal scrapers.
• Don’t use vinegar, bleach, or window cleaners.
• Don’t clean panels in the heat of the day.
• And definitely don’t walk on your panels — ever.

Eco-Friendly Cleaning Options

And since we are talking about cleaning options, let’s not ignore some of the eco-friendly solar panel cleaning options available:

• Deionized water: Reduces water spots and residue.
• Waterless sprays: Leave anti-static coating to repel dust.
• Robotic cleaners/drones: For large solar farms or tall buildings.

Does Panel Size Matter for Cleaning?

Yes — but mostly in terms of how you clean, not what you clean with.

For Small Setups (1–10 panels):

• Easy DIY job
• Takes about 30–60 minutes
• Low water and tool usage

For Mid-Sized Setups (10–50 panels):

• More time-consuming
• May need a water-fed pole, longer hose, or second person
• Do it in sections over a few hours

For Large Installations (50+ panels):

• Best handled professionally
• Robotic cleaners, rotating brushes, and deionized water systems are often used
• Logistics and safety become a real factor

 

Installation Size	Key Differences	Notes
Small (1–10 panels)	Easy DIY	Quick, low effort
Medium (10–50 panels)	Takes time, needs extensions/tools	Divide into sections
Large (50+ panels)	Needs team, possibly pro gear	Safety gear or robots recommended

 

Solartiqo Note:

For large-scale systems, dry cleaning (with solar-safe brushes) or water-fed poles with filtration becomes necessary. Also, record-keeping is crucial — log cleaning cycles, before-and-after photos, and any panel damage found.

So, Cleaning is an Investment, Not a Chore

Over the years, I’ve seen solar panels that lasted 25+ years with minimal degradation — not because they were the most expensive, but because they were maintained well.

Regular, correct cleaning:

• Boosts efficiency
• Prevents micro-cracks and hot spots
• Keeps warranties valid
• Saves money in the long run

If you clean them yourself, do it safely. If you hire someone, do it smartly. 

Either way, your solar panels deserve the same care you’d give to any energy-saving investment.

 

FAQs for Solar Panel Cleaning Process

Q1: Can I clean panels during the day?
Only in the early morning or evening, when the panels are cool. Sudden temperature changes can cause cracks.

Q2: What if I have hard water?
Use deionized or distilled water to avoid mineral spots that reduce efficiency.

Q3: Is rain enough in tropical areas?
Rain helps, but it doesn’t remove bird droppings, sticky grime, or pollution residue.

Q4: Should I apply any coatings or wax?
No. Panels are designed with anti-reflective coatings. Adding anything can reduce performance or void the warranty.