Keeping solar panels clean is not just a matter of aesthetics: dirt accumulation can reduce their efficiency by 15-25%. In this article we answer the most common questions about cleaning, frequency, suitable products and whether to do it yourself or hire a professional service.
Ideal cleaning frequency
General recommendation: clean every 6 to 12 months. However, this changes depending on location, climate and environment:
| Area or environment | Suggested frequency |
|---|---|
| Urban/industrial areas | Every 3-4 months |
| Rural areas with pollen | 2-3 times a year |
| Coastal zones | Every 2-4 months |
| Areas with dust, haze or desert | Every 1-2 months |
| Areas with frequent rainfall | 1 time per year (may be sufficient) |
Tip: monitor production. If it drops for no apparent reason, they probably need cleaning.
What happens if I don’t clean the solar panels?
- Decreased yield (up to 25 % less energy generated)
- Increased long-term wear and tear
- Lower amortization of solar investment
- Risk of persistent or corrosive dirt (saltpetre, excrements)
How to clean solar panels yourself?
- Use distilled or demineralized water.
- Use a soft sponge or soft bristle brush.
- Do not use chemicals or pressurized water
- Clean in the morning or in the evening, when the panels are cold.
- Rinse well to avoid residues
Avoid using ammonia, alcohol, common glass cleaners or abrasives.
When to hire a professional service?
- If the panels are on a roof or high location
- If you do not have adequate tools or security
- If there is stubborn dirt or difficult accumulation
- If you want to include cleaning in your preventative maintenance
The cost can range from 50 to 150 € depending on access and number of panels.
Recommended cleaning products
- Osmotized or distilled water
- Telescopic brushes with soft sponge
- Cleaning kit for solar panels (sold in specialized stores)
- Automatic cleaning robots (for large installations)
Most common types of dirt
- Dust and dirt
- Bird droppings
- Dried leaves and pollen
- Saltpeter (coastal areas)
- Soot and industry (urban areas)
FAQs: what users ask
Can I spray water on the panels?
Yes, but only if they are cold. Never use pressurized hoses or hot water.
What is the best time of day to clean?
Early in the morning or at dusk, as these are the hours with the least sun.
How long does a solar panel last if well maintained?
The service life can exceed 25-30 years if properly maintained.
What is the rule of 20 for solar panels?
Check every 20 days in critical areas (dust, saltpeter) and clean if necessary.
Is a professional service worth it?
If the panels are at height or you have doubts, yes, they guarantee safety and effective cleaning.
Cleaning your solar panels with the right frequency and the right methods ensures that your solar investment will perform at its best for more than two decades. If you have questions about the condition of your panels or want professional maintenance, we can help.
→ Request a no-obligation inspection or quotation.