To clean solar panels safely, rinse off loose dust first, wash the surface with a soft brush and purified water, rinse again, and let them air dry — always working early morning or evening, never in direct midday heat. The method matters more than the tools: the wrong technique is what causes most DIY damage, not the act of cleaning itself.
Here’s the full process, done properly.
What You’ll Need
- A soft, non-abrasive brush (a dedicated solar panel brush, not a stiff-bristled scrubber)
- Purified or deionised water where possible — tap water can leave mineral spots as it dries
- A hose with a gentle spray attachment, not a pressure washer
- A squeegee for the final pass, if you want a streak-free finish
- Fall protection or a stable, secure ladder if your roof access requires it
Step-by-Step: The Safe Method
1. Choose the right time. Clean early morning or in the evening, when the panels are cool. Cold water on hot glass can cause thermal shock — a rapid temperature change that can crack the panel surface.
2. Rinse first. Before touching anything, hose down the panels to remove loose dust, leaves, and debris. This step alone prevents you from grinding grit into the surface with the brush in the next step.
3. Wash with a soft brush and water only. Use gentle, straight-line strokes rather than circular scrubbing. Skip detergents, dish soap, and glass cleaners — most contain additives that leave a residue or streak once dry, and some can degrade the panel’s protective coating over time.
4. Rinse thoroughly. Make sure every trace of loosened grime is washed away before it has a chance to dry back onto the surface.
5. Let them air dry, or squeegee if needed. In most cases panels dry cleanly on their own. A squeegee pass helps if you’re in a high-mineral-content water area and want to avoid spotting.
Mistakes That Cause the Most Damage
The panel itself is more fragile than it looks. A cracked seal or a scratched coating doesn’t show up immediately — it shows up as reduced output months later.
- Using a pressure washer — the force can damage seals and push water into places it shouldn’t reach
- Cleaning in full midday sun — the thermal shock risk, plus water evaporates before it can lift grime
- Standing directly on the panels — this is both a safety risk and a real risk of cracking the glass
- Using household cleaning products — anything beyond water and a soft brush risks residue or coating damage
When to Call a Professional Instead
If your roof access is difficult, your system hasn’t been cleaned in over a year, or you’re simply not comfortable on a ladder at height, the risk profile changes. We’ve covered the fuller case for professional cleaning versus DIY in [Can You Clean Solar Panels Yourself?] — worth a read if you’re still weighing it up.
Prefer to skip the ladder entirely? Get a free quote and we’ll handle it with the same soft-wash method, plus before-and-after photos of the result.