How to clean solar panels? Complete guide (2026)
How to clean your solar panels yourself without causing damage? A step-by-step guide, what you should never use, and when it’s cheaper to call in a professional.
By Hendrik Vandervoort6 min read
Cleaning solar panels seems simple, but improper cleaning can cause scratches, reduce efficiency or even damage the coating. In this complete guide, you will discover how to clean solar panels safely and efficiently, what materials you need and when professional cleaning is the better choice.
At Solarco we clean solar panels professionally with pure water, as this is the safest and most efficient method. In this article, we explain how to clean solar panels best happens, why cleaning solar panels with pure water preferred and why you Cleaning solar panels with Dreft or rainwater better to avoid.
Why is solar panel cleaning important?
Solar panels are exposed to daily:
- dust and sand
- bird droppings
- pollen
- soot and particulate matter
- moss and algae growth
Even a thin layer of contamination can reduce efficiency by 5 to 15%. In industrial or rural environments, this can be even higher.
Regular solar panel cleaning helps to:
- extend the life of the installation
- maintain maximum energy yield
- avoiding hotspot formation
How to clean solar panels? Step-by-step instructions
Below is the safe roadmap.
🔧 Supplies
- Lukewarm pure water
- Soft brush or sponge
- Bucket
- Possibly telescopic handle
- Safety equipment (if required)
| Step | Action | Important |
|---|---|---|
| 1 | Switch off the installation | Safety first |
| 2 | Rinse with lukewarm lime-free water | Do not use high pressure |
| 3 | Use a soft brush | Avoid abrasive materials |
| 4 | Clean in cloudy weather | No cleaning on hot panels |
| 5 | Let dry without soap residue | Do not use aggressive products |
What should you NOT do when cleaning solar panels?
These are the most common mistakes:
- Using a high-pressure cleaner
- Use abrasive sponge or steel wool
- Applying chemical cleaners
- Cleaning in full sun
These faults can cause micro-cracks in the protective layer.
How often should you clean solar panels?
Average:
- Once a year in normal environment
- 2 times a year for high dust, agriculture or industry
Do you live close to trees or agriculture? Then more frequent cleaning may be necessary.
When is it better to choose professional cleaning?
Cleaning yourself is not always wise.
Professional cleaning is recommended for:
- High or difficult-to-reach installations
- Persistent limescale
- Security risk
- Large installations
Professional companies use pure water and special brush systems that do not scratch.
Want to know what this costs? Then take a look at our page on solar panel cleaning price.
Tip 1. Always use pure water - never clean solar panels with rainwater!
Many people think rain cleans, but cleaning solar panels with rainwater actually leads to streaking, scaling and lower yields. This is because rainwater contains minerals, dust, sand particles and often airborne pollutants (such as acid rain). When this dries up on the glass of your panels, it creates white chalk streaks and a sticky layer that attracts dirt - exactly the opposite of what you want to achieve.
Why cleaning solar panels with rainwater is not a good idea
- Lime and mineral residue: Rainwater contains calcium and magnesium that remain as white deposits when evaporated.
- Increased dirt holding capacity: The residue of dried rainwater forms a sticky layer that retains new dust and bird droppings faster.
- Reduced efficiency: Research shows that scale and stains can reduce energy output by 10-20%.
- No inspection or maintenance: Self-cleaning with rainwater offers no way to detect damage or micro-cracks early.
Advantages of pure water in solar panel cleaning
Pure water is completely free of minerals, lime and chemical contaminants. As a result, it offers streak-free, safe cleaning that does not affect the glass surface of your solar panels.
| Advantages of pure water | Disadvantages of rainwater |
|---|---|
| No lime streaks | Leaves white deposits |
| No chemical residues | Promotes dirt accumulation |
| Environmentally friendly | Increases maintenance frequency |
| Safe for glass | Can damage glass by minerals |
At Solarco, we combine pure water with soft, anti-scratch brushes and professional telescopic equipment. Thus we guarantee thorough, streak-free cleaning - without the disadvantages of cleaning solar panels with rainwater. Read on for the best tips on how to clean solar panels.
Tip 2. Never use Dreft or other detergents when cleaning solar panels
Although many homeowners think Cleaning solar panels with Dreft is a quick and cheap solution, in reality it is a recipe for trouble. Dreft and similar detergents contain oils and aggressive chemicals that leave a thin, greasy film on the glass surface. This film attracts new dirt, causing your panels to re-contaminate faster - and the efficiency drops by an average 10-20%
Why cleaning solar panels with Dreft is a bad idea
| Problem | Explanation |
|---|---|
| Greasy layer | Soap residue adheres to the glass, trapping dust and bird droppings |
| Damage coating | Chemical components attack the protective layer of solar panels, causing micro-cracks and loss of light transmission |
| Warranty risk | Use of Dreft can void manufacturer's warranty with many manufacturers |
"Cleaning solar panels with Dreft and other cleaning agents can reduce long-term energy yield." - Expert at Solarco
Comparison: Dreft versus pure water
| Method | Result | Impact on returns | Recommended? |
|---|---|---|---|
| Dreft / detergent | Leaves stains and film | -10-20% returns | ❌ |
| Pure water | Streak-free, limescale-free & safe | +10-20% yield | ✅ |
Best practice for solar panel cleaning
Use only pure water in combination with soft, anti-scratch brushes. This prevents residues, protects the coating and maximises your yield - with no risk to warranty or performance. Read on for the best tips on how to clean solar panels.
Read more about cleaning solar panels with dreft here
Tip 3. Cleaning Solar Panels with Rainwater? Not Effective!
A frequently asked question is: Can solar panels clean themselves with rainwater? The answer is no. Although rain sometimes washes away loose dust, it is insufficient to remove stubborn dirt, bird droppings and algae.
Why cleaning solar panels with rainwater is not a good idea:
- Rainwater contains pollution and limescale, which can cause streaking and staining.
- Bird droppings and mud are not washed away.
- In dry periods dust and sand sticking, reducing returns.
Rainwater alone is thus insufficient. For a truly clean installation, it is better to choose pure water cleaning by an expert. Check out our professional cleaning options or read on for the best tips on how to clean solar panels.
Tip 4. Use the Right Cleaning Equipment and Work Safely
If you want to clean your solar panels yourself, it is important to work safely and with the right equipment. Improper cleaning can not only damage your solar panels, but also be dangerous when working on a roof.
What NOT to do:
- No pressure washer! This can damage the seals and push water under the panels.
- No hard brushes or scouring sponges! These can scratch the glass and coating.
- No soap or chemicals! This can leave streaks and reduce light transmission.
What you WILL be able to do:
- Use a soft brush with a telescopic handle.
- Work with pure water for streak-free cleaning.
- Work safely: use a safety belt Or let a professional do the work.
No idea how to clean solar panels or have no experience with roof work or doubt about the right method? Then have your solar panels cleaned by Solarcoto make sure it is done safely and correctly or read on for the best tips on how to clean solar panels.
Tip 5. Have your solar panels professionally cleaned on a regular basis
To make your solar panels as efficiently as possible to make it work, is annual professional maintenance recommended. At Solarco we offer periodic cleaning services for both individuals as well as companies.
Why choose professionalcleaningby Solarco?
- Specialist pure water cleaning without streaking or damage.
- Experienced and certified professionals with safe practices.
- Fixed rates and transparent quotations with no hidden costs.
- Protection of your investment and maximum efficiency.
View our solar panel cleaning prices and ask for a free quoteto.
Cost of solar panel cleaning versus cleaning yourself
| Method | Cost per cleaning | Advantages & disadvantages | Source |
|---|---|---|---|
| Cleaning yourself | €10-€50 (sponge + lukewarm water) | ✔ Low cost✘ Risk of scratches, no inspection, little effect for stubborn dirt consumerbond.co.uk | Consumer Association |
| Professional cleaning | €125 for 1-25 panels (Solarco) | ✔ Safe, streak-free result✔ Inspection & reporting✔ Higher yield (+10-20%) milieucentraal.co.uk | Milieu Centraal |
Cleaning yourself with water and soft sponge is only effective for light soiling and carries warranty and safety risks. Professional cleaning delivers structurally more efficiency and prevents expensive repairs.
How to clean solar panels, the best service?
Don't just choose on price, but pay attention to quality, safety and transparency. Use this checklist:
| Criterion | What to look out for | Source |
|---|---|---|
| Certification & insurance | VCA/ISO certificate + liability insurance | RFO maintenance tip rvo.co.uk |
| Cleaning method | Pure water without chemicals | Consumer Association consumerbond.co.uk |
| Transparent tariffs | Fixed price for 1-25 panels + per-panel surcharge | - |
| Customer reviews & references | 4+ stars on Google or Trustpilot | - |
| Inclusive inspection | Checking for micro-cracks & inverter status | Milieu Centraal milieucentraal.co.uk |
Conclusion: How to Clean Solar Panels in the Best Way?
Cleaning solar panels is essential to maximum energy yield guarantee. However, not all methods are suitable. Here are the main points To remember about how to clean solar panels:
✅ Usage pure water for a safe, streak-free cleaning.
❌ Usage no Dreft or other cleaning agents - this leaves a film behind.
❌ Rainwater is not enough To keep solar panels clean.
✅ Usage the right equipment and work safe.
✅ Get your solar panels regular professional cleaning by Solarco.
No idea about how to clean solar panels? Want to be sure of a perfect cleaning without risks? Then choose a professional pure water cleaning by the experts of Solarco.
Find out more on our solar panel cleaning page.
🔗 Apply now for a non-binding quotation via our contact page.
📞 Or call directly: +32 468 18 56 40 We make sure your solar panels like new again perform!
Frequently asked questions
How does Solarco clean solar panels?
Solarco cleans with professional equipment: suitable non-abrasive brushes and purified water, without harsh cleaning agents or high pressure. For large installations and solar parks, we use battery-powered, manufacturer-certified cleaning robots. A visual check and, if required, a thermographic check are carried out before and after cleaning.
What equipment do you need to clean solar panels safely?
Safe cleaning calls for suitable non-abrasive brushes (with soft, flagged bristles that won't scratch) and pure water, without harsh cleaning agents or high pressure. A rubber squeegee used in one smooth downward stroke prevents streaks. For high or large roofs, professionals use telescopic poles or a cleaning robot, so nobody has to stand on the panels.
Can you use a pressure washer or Kärcher on solar panels?
No, never use a pressure washer. The high pressure can cause micro-cracks, damage the seals around the panel and force water into the junction boxes, leading to faults and lost yield. Always clean at low pressure, with pure water and a soft, non-abrasive brush.
Can you clean solar panels with washing-up liquid?
No, washing-up liquid or soap is not recommended, because it leaves a thin film that attracts dirt and causes streaks every time it rains. That soap film absorbs light and so reduces output, while alkaline products can damage the coating over time. Clean with pure water and suitable brushes instead, without soap.
Does rain clean solar panels?
No. Rain only washes away loose dust and often leaves minerals and stubborn dirt behind. Moss, lichen, bird droppings, pollen, Saharan sand and industrial fallout stay stuck to the panels, and it's precisely these layers that cost the most yield. Even a thin layer of dirt can mean 5 to 10% less output.
What mistakes should you avoid when cleaning solar panels yourself?
Avoid pressure washers, hard or abrasive brushes, steel wool and household cleaning products, as they damage the coating and seals. Never clean the panels dry (this creates static and scratches) and never in full sun, because the water evaporates too quickly and leaves streaks. Don't use cold water on hot panels, to prevent thermal shock and micro-cracks.
