How to clean solar panels safely and boost efficiency?

Solar panels are a vital part of the clean energy revolution, converting sunlight into electricity for homes and businesses.

However, their efficiency can drop by 15–25% when covered in dust, pollen, bird droppings, or debris, according to the National Renewable Energy Laboratory (NREL). Regular cleaning is essential to maintain peak performance.

This guide outlines expert-recommended tools, cleaning techniques, and safety practices for both homeowners and professionals.

Essential tools and materials

Soft-bristled brush: Prevents scratching the panel surface. Opt for a long pole version to reach rooftop installations.

Squeegee: Ensures streak-free drying.

Low-pressure hose: A standard garden hose is sufficient for rinsing without damaging the solar panels.

Telescopic pole: Useful for high or awkwardly placed solar panels.

Deionized or distilled water: Prevents mineral spotting.

Mild dish soap: Safe for removing grime without harming panel coatings.

Vinegar solution: A 1:1 vinegar-to-water mix can help remove stubborn stains.

Safety gear:

Non-slip shoes and gloves

Fall protection harness (for rooftop access)

Safety glasses and a helmet

Step-by-step cleaning process

1. Preparation

Choose a cool, overcast day to prevent quick evaporation and streaking.

Turn off the solar system completely to eliminate electrical hazards.

Ensure secure access to solar panels (use ladders safely).

2. Initial Rinse

Use a low-pressure hose to rinse off dust and loose debris.

Start rinsing from the top and move downward to avoid redistributing dirt.

3. Surface Cleaning

Mix soap with deionized water.

Use a soft-bristled brush to gently clean the panel surface.

For stubborn areas (e.g., bird droppings), let the solution sit for 1–2 minutes before scrubbing lightly.

4. Rinsing and Drying

Rinse thoroughly with clean water.

Use a squeegee for a spot-free finish, working from top to bottom.

If air-drying, ensure no hard water residue is left on the surface.

5. Post-Cleaning Inspection

Look for missed spots, streaks, or damage.

Check for any loose wires or cracks in the glass.

Turn the system back on and monitor performance.

Safety guidelines

Electrical safety:

Never clean while the system is live.

Avoid spraying water near junction boxes, inverters, or exposed wiring.

Panel protection:

Follow manufacturer instructions.

Do not walk on panels or use high-pressure washers.

Use only approved tools to avoid damaging the surface.

How often should you clean your solar panels?

Frequency Depends On:

Climate: Dusty, desert, or coastal areas need more frequent cleaning.

Season: Spring pollen or winter snow can affect performance.

Tilt: Panels with a tilt over 15° may self-clean during rainfall.

Location: Panels near factories or roads may accumulate more dirt.