Your Yearly Solar Panel Cleaning - Beacon

Your Yearly Solar Panel Cleaning

Once you’ve expended the money to install a photovoltaic system, you can reap the financial rewards of tiny or non-existent electrical bills. Maybe you even receive a stipend for contributing electricity back to the grid. Certainly, you can feel great about doing your part to employ renewable energy, relieving a little pressure on the environment.

But to keep your system operating at peak capacity, those panels need to be cleaned at least once per year.

Dirty Panels = Efficiency Loss

When dirt, grime, pollen, salt and pollution settle on your solar panels, they create some shade, the mortal enemy of efficient conversion of sun to electricity. Depending on other factors, including the degree of tilt and amount of solids on the glass, you could lose from 1 to 30 percent of your solar output.


If your panel mounts provide a fairly vertical angle, the easier it is for rain to wash most of the dust off the panels. The more horizontal they are, however, the more dust will settle and become water spots when the rain dries.


Solid soiling from bird droppings, stuck leaves and even hard water deposits will knock out a lot of production. If you monitor your system daily and see a significant loss of output, you may have debris on the panels that should be washed off as soon as possible.

Best Methods to Clean Solar Panels

Cleaning your solar panels constitutes a bit of a chore like cleaning your windows. You’ll need to haul to your roof:

  1. a water hose or pressure washer
  2. a cleaning agent
  3. a soft cleaning tool, such as a long-handled brush or sponge
  4. a wide-bladed squeegee.

Avoid the Sun

Never wash your panels in full sun. The sun may cause streaking, and cold water hitting hot glass could crack it and cost you a pretty penny. Clean only in the cool morning, on a cloudy day or in the evening, but always test the temperature of the glass first.

Use Only Filtered Water

If you have very hard water or well water, you may need to filter it before you spray. Minerals and sediment in the water can leave a build-up at the very least or scratch the glass at the worst. Although the residue of hard water may be invisible, bacteria and algae will find it a very hospitable place to set up housekeeping. Once they spread across the glass, you could find yourself cleaning your panels all over again in a few short months.

Dangers of Water and Steep Roof Slopes

Beware of the water on your roof when you wash the panels. Even asphalt roofs can become very slippery with enough water or if you’re farming moss above your head. Tile, wood, standing seam metal, slate and plastic shingles will become water slides without the fun (or the pool) when wet, so you must work with superb care.

Another option would be to purchase your own fall protection gear, then learn how to set it up and use it. On slick roof systems, you most likely need buckets of clean water, rather than the hose, in order to control where the water hits the roof and where you can safely place your feet, unless you feel comfortable working off of a ladder. But remember, too, that ladders also become slippery when wet.

Hire a Professional, Save a Bundle on Bundled Services

To prevent accidents, you may prefer to hire a professional cleaning company to remove the grime from your solar panels while you sip lemonade from the safety of the ground. If so, you may want to include window washing, roof cleaning or other exterior cleaning projects at the same time. By doing so, you may see a significant discount with a package deal. Since you won’t have to pay for all the trip fees one at a time, you already preserve some hard-earned cash.

Combining solar panel cleaning with window washing, algae removal and protection on your roof and/or siding, plus a good concrete power wash to eliminate oil stains in your garage or on your driveway will save you quite a bit. How are your deck and pool apron looking these days? Bundle them all together for the maximum money-saving plan.

We at Beacon Roofing and Exterior Cleaning know exactly how to safely clean your solar panels. We even developed a revolutionary mobile filtration system that generates 100 percent clean water on site, no matter the hardness of your water supply. If your solar system is losing steam and you prefer to remain on terra firma, please give us a call or click to schedule your free quote today.


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