How to Clean Solar Panels: A Step-by-Step DIY Guide

As you already know, residential and off-grid solar systems are amazing sources of renewable energy that are quickly growing in popularity. The large flat glass panels harness the sun’s light to generate electricity that can be used and/or stored to power a home. Solar energy has many benefits, such as lower energy bills (or zero energy bills), less environmental impact, and either partial or complete independence from the grid. 

Solar Panels Covering Rooftop of Mountain Home off the grid

Solar is also becoming more accessible, especially with the help of some of the solar panel companies that offer complete solar kits. However, solar panels only pay off if they produce enough energy to supply the electricity needs of the home. The production of that energy depends on how much sunlight the panels can absorb, so if solar panels are dirty, they won’t work as well as they could.

Generally, the best solar panels don’t need much cleaning and maintenance in places that get regular rain. Rain can clean most of the dirt and debris that might prevent the solar panels from operating at peak efficiency by getting the most sunlight possible. However, dirt can still accumulate over time. In dry or dusty areas, near building or industrial sites, or if you have a rooftop chimney or stove pipe, rain may not be enough to keep the panels clean.

Image of dirty solar panels with

Learning how to clean solar panels can help homeowners save money on solar panel maintenance costs.

Image of man cleaning solar panels and "How to clean solar panels" in text across the image

Table of Contents

Why do solar panels need to be cleaned?

The answer is simple: dirt, dust, debris, bird droppings, and other contaminants can accumulate on the surface of your solar panels over time.

Even when the panels may look clean after a heavy rain, they can still harbor a thin film of these contaminants. This will prevent 100% of the sunlight from reaching the solar cells, reducing the amount of electricity they can produce.

According to some studies, dirty solar panels can lose up to 35% of their efficiency compared to ones that have been properly cleaned.

Image of dirty solar panel with

Below are energy production percentages you may lose per quarter if you fail to give your panels the required cleaning.

  • Year 1 Q1: 5% Energy Loss
  • Year 1 Q2: 10% Energy Loss
  • Year 1 Q3: 15% Energy Loss
  • Year 1 Q4: 20% Energy Loss
  • Year 2 Q1: 25% Energy Loss
  • Year 2 Q2: 30% Energy Loss
  • Year 2 Q3: 35% Energy Loss

How often should you clean your solar panels?

The answer depends on several factors, such as the location, climate, angle, and type of your solar panels.

Generally speaking, you should clean your solar panels at least once or twice a year, preferably in the spring and fall. If you have trees nearby that drop leaves then late fall may be best. However, you may need to clean them more frequently if you live in a dusty or polluted area, or if you experience heavy rain, snow, or wind. We’ll discuss snow removal in a separate post.