How to clean solar panels?

The most efficient homes and even commercial buildings nowadays have solar panels lining their roofs that help account for up to 30-90% of their total consumption requirements.

However, the thing with solar panels is that they have to be in places that are hit by the sun – the same places that are heavily exposed to dust, grime, and occasional bird droppings. 

For solar panels to function optimally, they need to be clean, which is exactly what this guide is all about.

How does buildup affect solar panel’s efficacy?

Solar panels rely on the photovoltaic cells found in their panels in order to generate power.

As such, the performance of a solar panel is directly proportional to the condition of the panels – the clearer the surface, the higher amounts of solar energy the cells can absorb.

A solar panel owner should know how to clean solar panels, just like a real DIYer.

The build-up of foreign material on the panels is said to be able to reduce performance by as much as 0.05% per day according to USCD [1].

How often should you clean solar panels on the roof?

Depending on where you’re located, we advise that you should routinely clean your panels every 6 months to a year.

Taking into account your area’s pollution and changes in weather and climate, this minimum of once a year can fluctuate and will definitely increase in more urbanized locations that experience less rainfall.

Cleaning solar panels: DIY vs Hiring professionals

DIY cleaning

Advantages

• More affordable. Cleaning solar panels on your own means that you don’t have to pay for labor and miscellaneous fees.
• Builds familiarity. Every time you clean your solar panels, you get to view them more and develop a further understanding of how they are kinda magic. While giving you an opportunity to have a visual check over on the other components on your roof. This knowledge makes it easier for you to better care for your panels and your roof in the future.
• Facilitates consistency. You’d want your panels to always be at 100%. To achieve this, you must have the discipline to always carry out routine cleaning and maintenance to help preserve their optimum efficiency. The more you follow a cleaning schedule over your whole home, the more discipline you also build.

Disadvantages

• Proper maintenance. Especially for new and totally unfamiliar owners, a lack of proper know-how for solar panels cleaning and maintaining solar panels can lead to eventual damage and/or reduced efficiency. 
• Risk/Hazard. Especially for panels on the roof of tall buildings/houses, cleaning can be arduous and relatively dangerous. Panels that cannot be reached safely will require the use of a mop on an extendable pole. And maybe even a scissor lift.

Hiring professionals

Advantages

• Skills and knowledge. They’re professionals because they’re undergone extensive training and learning in relation to their work and safely doing it. They have the understanding and ability on how to keep solar panels clean effectively and keep them that way for some time.
• Value-added. Part of a professional cleaning solar panels companies ‘service is often including additional service beyond just cleaning. Professionals can make tweaks, minor adjustments, and even other small repairs at no extra charge. 
• Can help guarantee panel longevity. Good service will build good customer relations. If you’re happy with what you were given, then it potentially gives you dependable, quality cleaners that will help add years to your solar panels and your home’s appearance.

Disadvantages

• Less affordable. Hiring a professional cleaning service will definitely cost something as you pay extra for labor and equipment. 
• Security. Not meaning to paint a bad picture, but remember that you are still inviting strangers into your home and will be exposing some of your privacy. 
• Conflict of interest. As professionals, not all of them might adhere to the way you want things done. There are instances where “I know more than you” or “I know better” could arise.

What do you need when cleaning solar panels on the roof?

You actually only need a few things:

• A ladder (optional).
• A sponge or soft cloth (optional).
• A bucket or hose.
• A medium to soft brush on an extendable pole.
• A mixture of mild soapy water

How to clean a solar panel on the roof?

You can do this by yourself, but having an extra hand or two bits of help, especially if you have a good number of large panels, or if you need someone to stabilize the ladder. 

Procedure:

1. Keep in mind the layout of your roof and the positioning of your panels. This allows you to better and more easily position yourself come cleaning time. 
2. Identify the amount of build-up. Knowing how much needs to be cleaned will determine what cleaning product you’ll be using. Generally lighter build-up only needs a bucket, some mild soapy water, and a squeegee, and a sponge on a pole. 
3. Once in a favorable position, rinse off the panels first with plain water from the hose to wash away any loose dirt. 
4. Next, begin gently washing the panels using soapy water and a sponge or soft brush scrubber. Get at persistent stains and residue not washed off by the initial rinse.
5. Rinse for a second time to get rid of soap bubbles and liquid residue.
6. Squeegee dry. 
7. If some grime remains, repeat steps 3 to 6, changing positions as needed until all panels are dirt-free and shiny!

Extra care tips

• Especially if your panels can tilt, adjust them so that they’re at least greater than 10° to reduce the time it takes to accumulate build-up. 
• If you live in a relatively dry area, consider a quick hose-down of your panels twice a month.
• Consider getting a commercial PV protective screen if you live near heavily industrialized or urban-polluted areas.

Of course, you don’t want your roof ending in further damage.

How to clean RV solar panels?

Things you’ll need: A bucket, a sponge/scrubber, a squeegee or soft cloth, *rain.

Procedure:

1. If you plan to clean manually, pull over at a suitable location that’s preferably near a water source. And a high platform you can park next to and stand on.
2. Head on next to the RV’s roof and rinse down the panels with a hose. 
3. Gently wash off any dirt or grime that is stuck using a sponge or soft cloth.
4. Rinse again then squeegee.
5. If on the road, drive and let the panels soak in the rain then pull over to squeegee them dry and get rid of muck, like bird droppings and soggy leaves.
6. Driving down the motorway during a storm is also an effective way to get most of the job.

How to clean solar panels on garden lights?

Things you’ll need: Alcohol/water, soft bristle brush, sponge or soft cloth, dishwashing liquid, a towel. 

Procedure:

1. Lightly dab some hot water on top of the light’s cover to separate any loose dirt.
2. Take the top cover and wipe it down along with a mixture of mild detergent water.
3. Use the soft bristle brush to get at dirt accumulated in corners and tight spots.
4. Rinse with clean water and dry by lightly dabbing with a wiping cloth.
5. Do a second pass but this time with alcohol.
6. Rinse with clean water and wipe dry.

Dos and don’ts when cleaning solar panels

Here are our tips for cleaning solar panels:

Dos

• Turn off the panels (disconnect them from the batteries or inverter). This stops voltage flow and prevents any shock hazards as well as lowers the chances of shorting any ports. 
• Do make use of soft wipers. Sponges, squeegees, and soft scrubbers work perfectly since they’re less likely to scratch the panels. They are made from glass and can handle a medium bristle brush.
• Do use distilled water as much as possible. This eliminates the chance of leaving mineral deposits on panels.

Don’ts

• Don’t use soap [2]. If you will use soap, then use only a tiny amount in a mild concentration with water. 
• Don’t ever walk or put anything on top of panels to get to other ones.
• Don’t use detergents to clean as they’re too abrasive for the panels and leave behind a film-like residue that adds to opacity and encourages faster accumulation.

Conclusion

Solar panels are great and they’re not too complicated to clean when needed. What most people tend to overlook is the fact that you actually have to clean them instead of leaving it all to the weather.

Though not a big dip, build-up left to sit can reduce a panel’s efficiency by 2-3% per year. If you want your solar panels to keep operating in peak condition, then the best you can do is to actually make sure they stay clean.

Lastly, make sure you don’t work from a height you’re not comfortable at, and without proper safety precautions, we don’t want to come and clean up the pavement later.

If you have gone off-grid, cleaning is just the basics of maintaining a solar system.