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Why you should clean and maintain your solar panels

Clean solar panels

Key points

Dirty solar panels are much less efficient, reducing your savings
Safety is paramount when cleaning solar panels yourself
Check with the manufacturer that cleaning panels won’t affect your warranty
Solar panels require very little maintenance

Why cleaning your solar panels is important

Out on the roof, your solar panels can accumulate layers of:

grime
dust
tree sap
bird droppings

These stop daylight from getting through to the panels, which makes them less efficient.

However, there is debate over whether cleaning is necessary. Some people recommend yearly cleaning, while others say it’s only needed if:

where you live is particularly dusty (e.g. beside a busy road)
your roof is exposed to bird droppings or trees (e.g. beneath power lines or near a park)

Unfortunately, letting the rain do the job might not work. Rainfall can actually worsen the situation by washing dust into the corners of the panels. This causes them to heat up, which again lessens their efficiency.

Do it yourself or call in the professionals?

It’s certainly more cost-effective to clean your panels yourself. There are, however, important aspects to consider regarding:

safety
avoiding damage that could invalidate the panels’ warranty

We always recommend that you check with the manufacturer before attempting to clean solar panels yourself. If you still intend to go ahead with the cleaning, here are some tips:

Tips for cleaning solar panels yourself

Be safe	Always shut off your solar system beforehand—this will remove any risk of you being electrocuted. Inspecting solar panels means using a long ladder and special safety harness. If you aren’t experienced at doing this, or lack the proper equipment, don’t go up on the roof! Clean your panels with your feet firmly on the ground by using a telescopic extendable brush or squeegee. Do an online search for ‘solar panel cleaning kits’ and you should find plenty of retailers selling everything you need.
Use equipment that’s fit for purpose	Make sure any brushes, sponges or cleaning products you use are not so abrasive that they scratch the surface of the panels. Don’t use high-pressure jet washers—these can also cause damage.
Avoid hard water	Filter (or ‘soften’) hard water (tap water that contains a lot of minerals) before you use it to clean your solar panels. Untreated hard water can leave a film of calcium on the panels that, over time, can cause them permanent damage. You can buy special water softeners online.
Check the weather	Clean when the weather’s cooler and darker, as the panels won’t be as hot. Some manufacturers advise against spraying cold water onto hot panels, while there’s also the issue of your soap solution drying and leaving streaks before you can rinse it off.

Hiring a cleaning company

If you’d rather employ someone to do the work for you—whether it’s a solar panel cleaning company or your everyday window-cleaner—always make sure they have the necessary experience and can demonstrate that they’ll do a professional job.

Any company or tradesperson worth their salt will:

know what’s required to clean solar panels
understand how to prevent damage to the panels, your guttering and roof
use cleaning products that don’t contain any harmful chemicals
work safely at all times

Maintenance

Aside from cleaning your solar panels once a year, there isn’t much more you need to do. Solar panels don’t contain any moving parts and won’t rust or break down, so require little in the way of maintenance.

In the unlikely event that something does go wrong, contact the installer. They can give advice over the phone and will come out if necessary. The most common issues can be resolved simply by resetting the inverter.

The installer might charge for the call-out if your panels are no longer under the installer’s workmanship warranty (typically 12 months).