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. 

Clean Your Solar Panels Every Six Months

So, how exactly do you clean your solar panels properly? Thankfully the answer isn’t complicated, but it does require some planning, preparation, and exercising caution.

You can choose to DIY clean your solar panels using simple tools and materials, or ultimately you can hire a professional solar panel cleaning service to do it for you. Either way, you need to follow some basic steps and best practices to ensure safety and quality.

In this article, we’ll show you how to clean your solar panels safely yourself using simple tools and materials that are easily available. We’ll also provide you with tips and tricks to make the process easier and more effective.

By following this step-by-step guide, you’ll be able to clean your solar panels quickly and efficiently, and regain their maximum efficiency fast.

5 Simple Steps to Clean Solar Panels

The first step to clean your solar panels is to gather the necessary tools and materials. You don’t need any fancy or expensive equipment, just some common items that you probably already have at home or can easily find at your local hardware store.

Image of man cleaning solar panels on ladder with an extension pole

Step 1: Gather the necessary tools and materials

Here is a list of what you will need:

  • A ladder: You will need a ladder to access your solar panels, especially if they are mounted on the roof. Make sure the ladder is sturdy, stable, and long enough to reach the panels safely. You may also need a helper to hold the ladder for you or to hand you the tools and materials. We like this telescoping ladder for at the cabin as its easily showable, 
  • A hose: You will need a hose and spray nozzle to wet and rinse your solar panels with water. Make sure the hose is long enough to reach the panels from the nearest water source. You may also need a nozzle or a spray attachment to control the water pressure and direction.
  • A bucket: Choose a bucket is large enough to fit the sponge, the brush, and the squeegee. We like using a large rectangular bucket that tends to stay more securely on our metal roof. You may also want to use a lid or a cover to prevent the water from spilling or evaporating.
  • A sponge: If your washing my hang a large soft sponge is great as it holds plenty of water and detergent to wash an entire panel. Make sure the sponge is soft, clean, and non-abrasive. You may also need a scrubber to remove stubborn dirt or stains. Our scrubber of choice is the scrub daddy sponge
  • A soft brush: They make very soft bristled brushes that are perfect for washing solar panels. Again, make sure the brush is soft, clean, and non-abrasive. You can find brushes that attach to long telescoping handles or extension pole to reach panels that otherwise would be too difficult to reach.
  • A squeegee: A squeegee works to dry the solar panels quickly and prevent water from drying, spotting and leaving a film that we’ve been trying to remove. Make sure the squeegee is flexible and wide enough. There are brush, cloth, squeegee combo heads that we will discuss further below.
  • A cloth: Microfiber cloths work great to dry and polish your solar panels. Use them to help remove any streaks, spots, or residues.
  • A mild detergent: There are solar panel specific mild detergents to wash your solar panels. Of course you can use dish soap like Dawn. Just make sure the detergent is biodegradable, eco-friendly, and non-corrosive. You may also need a vinegar solution to remove any hard water deposits or mineral buildup.

Some optional or alternative tools and materials that you consider are:

  • A garden pump sprayer: You may want to use a spray bottle to wash your solar panels with water and detergent. This can help you apply the detergent more evenly and efficiently, as well as reduce the amount of water and detergent you need. For folks off the grid water may not be as plentiful and a small pump sprayer can help to cut back on water usage. We use a garden sprayer to apply a sudsy coating and let that sit for five to ten minutes before rinsing it off.

Garden Pump Sprayer for cleaning solar panels

  • A Backpack sprayer: If you don’t want to have to lug up the roof, buckets or soapy water, and try and balance a bucker of soapy water on an angles roof then you might consider a backpack sprayer. You can add soapy water to the tank, spray down the panels and let it sit before topping up the tank with fresh water and cleaning off the panels.

D.B. Smith Field King 4 gallon Backpack Sprayer used to clean off solar panels

  • A cordless leaf blower: You may want to use a blower to help dry your solar panels quicker. This can help prevent any water spots or residues from forming. However, you need to make sure the blower is clean and has a low or medium speed setting. You also need to avoid blowing any dust or debris onto the panels.