How To Clean Your Rooftop Solar Panels In Order To Promote Efficiency

Posted on: 20 April 2016


By the end of 2016, an estimated one million American homes will have solar panels, which is over thirty times the number of homes just a decade ago. As a result, most of these homeowners are saving thousands of dollars over the lifespan of their panels, and the total reduction in American energy costs is huge. However, if homeowners fail to keep their solar panels clean, they are depriving themselves of much of the benefit offered by solar panels. Below is how homeowners can clean their own roof-mounted solar panels and maintain a peak level of electricity generation:

How often should roof-mounted solar panels be cleaned?

Many solar panels are installed on the roofs of homes which is a convenient, safe and ideal location in most cases. However, since these panels are often out-of-sight of the homeowner, they can be neglected and allowed to become excessively dirty. That means cleaning should become a routine that is scheduled in advance by owners as part of the home's regular maintenance cycle.

All roof-mounted solar panels should be cleaned a minimum of once per year regardless of location. However, for many homeowners, cleaning should be conducted more often. Here are a few mitigating factors that may affect the number of cleanings that should be performed:

  • Proximity to rural roads and farmland

  • Density of bird populations

  • Nearby sap-producing trees

  • Time of year (for example, pollen levels increase in spring)

  • Ambient pollution from smoke, industry or other emissions

Take into consideration these above factors and determine how often you need to clean your solar panels. Keep in mind you may need to increase the frequency of cleanings if the panels are excessively dirty when you perform your subsequent cleanings.

Tools and materials needed

To successfully clean your solar panels, you will only need a few basic tools and supplies:

  • Five-gallon bucket

  • Soft-bristle brush suitable for use with car washing

  • Liquid dishwashing soap

  • Squeegee

  • Razor blade scraper

  • Garden hose with spray nozzle

  • Window cleaner spray and clean rag

  • Non-slip work shoes

  • Ladder

Step-by-step procedure for cleaning

1. Assess your personal level of safety - Before beginning the process of cleaning your solar panels, you will need to make a decision about your own personal ability to safely clean your roof-mounted panels. You can evaluate your own personal level of risk by looking at the slope of your roof--the steeper it is, the more difficult it will be to safely walk without slipping--as well as how much bare roof space is available to maneuver around the panels. If you believe the job is too difficult, don't hesitate to contact a professional service to perform the cleaning; your life is not worth risking to save a few dollars. A roofing contractor like Davis & Winslow Roofing may be able to clean your panels for you.

2. Set up your cleaning station - Once you make the decision to clean the panels, carry your empty five-gallon bucket to the top of the roof with your squeegee, brush, soap bottle and razor blade scraper. Next, pull your garden hose and nozzle up onto the roof and fill the bucket with water; add a couple of teaspoons of soap to the bucket and agitate the soapy water with your brush head. Be sure to wear slip-resistant shoes when walking on the roof surface.

3. Rinse the solar panels thoroughly - With your hose nozzle in hand, spray the solar panels thoroughly to remove any loose, abrasive particles that may be on top of the glass. If your roof consists of composition asphalt shingles, then you will need to be extra diligent to spray off the tiny, hard rock particles that are blown from the shingles. These can cause scratching of the panel glass and lead to permanent loss of clarity and reduced efficiency.

4. Wash the solar panels with the brush - Once you have rinsed the panels, soak the head of your brush in the bucket of soapy water, then use it to wash the glass. You may need to apply extra "muscle" for particularly dirty panels with caked layers of dust and dirt.

5. Rinse the panels with the hose and squeegee them dry - After washing the solar panels with the brush and soap, rinse them again with your hose to remove the soap. Next, place the squeegee at the top of the panel, then pull it downward to remove the water from the glass and prevent spotting.

6. Scrape stubborn spots with a razor blade scraper - The last step in cleaning is to inspect the cleaned glass for accumulations of bird droppings, sap or other stuck-on debris. Use a razor blade scraper to carefully remove these bits of debris, then spot-clean the area with a spray bottle of window cleaner and a clean rag.