The short answer
For most homes in Malta, cleaning solar panels once or twice a year is enough, ideally in spring before the long summer days. Homes near the sea, fields, quarries or building sites, and any roof that has just had a dusty rain, usually benefit from an extra clean. The best guide is your own system's readings on clear days.
Why panels in Malta get dirty faster than you might expect
A solar panel turns the light that reaches its cells into electricity. Anything that sits on the glass, from a thin film of dust to a single bird dropping, blocks some of that light. In Malta several things work against clean panels at once:
- Long dry summers. From late spring to early autumn there is very little rain, so dust simply builds up.
- Saharan dust. When the xlokk (sirocco) blows from the south, it carries fine dust from North Africa. When that dust comes down with rain it leaves the reddish, muddy residue people call red rain.
- Salt. Much of the islands is close to the sea. Salt carried on the wind dries onto glass as a hazy film.
- Construction and quarries. Building work is constant in many localities, and some villages sit near quarries or open fields.
- Birds. Pigeons and gulls love flat roofs, and droppings stick hard once baked in the sun.
How often to clean, by type of home
| Situation | Suggested cleaning |
|---|---|
| Typical home inland, no building work nearby | Once a year, in spring |
| Seafront or coastal home | Twice a year, spring and late summer |
| Near a building site, quarry or open fields | Twice a year, plus after any heavy dust episode |
| Regular bird problem | Spot-clean droppings as they appear, full clean once or twice a year |
| Holiday home used mainly in summer | Once a year, just before the season |
These are starting points, not rules. Your own readings will tell you more than any schedule. Do not count on the rain to do it for you: see does rain clean solar panels?
How to tell your panels need cleaning
Check your readings
Most inverters and solar apps show daily production. Compare a clear, sunny day now with a similar day a few weeks after the last clean, or with the same month last year. A steady drop on clear days, with nothing else changed, usually points to dirt.
Look at the glass
From a safe spot, look for a dull or hazy surface, brown streaks along the bottom edge where water runs off, or bird droppings. If you can see it from the ground or a neighbouring roof, it is affecting output.
After a dust episode
If cars and balconies are covered in red dust after a rainy sirocco day, your panels are too. Our guide to red rain and Saharan dust explains what it does to panels.
If output has dropped and the panels look clean, see why solar output is low, and for how to measure the gain from a clean, does cleaning solar panels increase output?
When is the best time of year?
Spring is the most useful moment. Panels produce the most between May and September, so starting that stretch with clean glass gives you the biggest return. A second clean in late summer or early autumn suits coastal and dusty locations.
Clean early in the morning or in the evening if possible. Cold water on hot glass in the middle of a summer day can stress the panel, and water dries too quickly to rinse properly.
Can you clean them yourself?
You can, if the panels are easy and safe to reach. Many are not: they sit on roofs without railings, on raised frames, or above a drop. Falls from roofs are a real risk, so if in doubt, do not go up.
If you do it yourself:
- Switch off following your installer’s instructions, if they recommend it.
- Rinse first with plenty of water to loosen dust and salt.
- Use a soft brush or sponge on an extension pole. Never use abrasive pads, scrapers or stiff brushes.
- Avoid harsh chemicals. Plain water is usually enough. If you need something stronger, use a product your panel manufacturer approves.
- Do not use a pressure washer. High pressure can damage seals and the coating on the glass.
- Mind the water. Hard tap water can leave mineral spots as it dries. Professionals often use purified water for this reason.
- Do not walk on the panels.
Bird droppings need soaking rather than scrubbing. See bird droppings on solar panels.
Our full guide on whether you can clean solar panels yourself covers which roofs are safe and which are not.
What a professional clean includes
A proper clean should leave the glass clear without streaks, deal with bird droppings and stubborn spots individually, and include a quick visual check for cracked glass, loose fixings or damaged cabling. You should get before and after photos.
clear.mt arranges solar panel cleaning across Malta and Gozo. Price usually depends on the number of panels and how easy the roof is to reach. Shared roofs on apartment blocks can often be cleaned in one visit for several owners, which can lower the cost per home.
If you also have a solar water heater, its glass or tubes can be cleaned at the same visit. See solar water heater care in Malta.
Warranty and manufacturer guidance
Check your panel manufacturer’s cleaning instructions, which are usually in the installation or warranty documents. Most advise soft brushes and water, and warn against abrasive tools and high pressure. Following them protects both the panels and your warranty.
See does cleaning solar panels void the warranty for the methods to avoid and how to keep a simple cleaning record.