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Article by George / July 20th, 2022

How to Clean Roof Solar Panels

Solar panel efficiency is the measure of how much sunlight a panel can capture and convert into usable energy. The higher its efficiency, the more energy it produces from the same amount of sunlight. Solar panels’ can be hindered by dirt, grime and other debris.

 Solar panels should be kept as clean as possible to increase their efficiency and lifespan. There are many factors that determine how well your solar panels will work in any given location; debris, weather and pollution are some of the most common culprits. 

Clean solar panels not only help them last longer but also allow for greater energy efficiency, which is something that could save you money on your next utility bill.

Generally, cleaning solar panels is rather simple and won’t take very long at all. Let’s take a look at how to properly clean roof solar panels, whether they’re on your home or business!

How Location Affects Solar Panel Cleaning

The main factor that determines how often you’ll need to clean solar panels is how dirty your location is. If you live in a very clean, low-traffic area, you may not need to clean your solar panels very often. Areas with more traffic and dirt are going to need cleaning more often. If you’re wondering if your solar panels need to be cleaned, think about the following locations: 

  • High-pollution areas – Solar panels that are installed close to airports, factories, docks, and highways will experience more atmospheric grime. Pollutants rise and get caught in the clouds, and in turn, are returned to the earth with the next rain.
  • Farmland – During the hotter months farmland can become quite dry. As the winds flow across the flatlands it picks up the dry dirt and transfers it to everywhere in its path. A light rain may come soon afterwards and turn the dirt on your solar panels to a thin mud consistency.
  • Wooded Areas – It goes without saying that if you live near trees then there will be leaves everywhere. Although leaves aren’t that difficult to remove, there are also small twigs or pieces of bark that can accompany them. This increases the chances of tree sap landing on your solar panels. Also consider wildlife, i.e. birds and the droppings they leave behind. Pollen and solar panels don’t mix. It’s sticky and accumulates quickly during pollen season. It also allows everything else to stick to it.
  • Desert Areas – Places like Houston can have an incredible amount of dust dropped on them from Saharan dust plumes. Sand not only reduces the efficiency of solar panels, but it can also scratch the soda-lime glass your panels are made of. Scratches are gateways for dust, dirt and other debris, giving them access to hang out and stay awhile.
  • Other Considerations – The recent increase in wildfires have created a problem for solar panel owners. Excess ash can block solar panels and get clogged in areas that can limit, or even stop, a solar panel’s ability to work properly.

How to Gauge when it’s Time to Clean Solar Panels

If you notice a steep decline in your power output, then it’s time to clean your solar panels. That’s the easy answer, but not the best. You can lose up to 5 percent of your energy output in a year, and in some cases that number can climb to 7 or 8 percent. Some don’t want to spend the money for having them cleaned, since it will cost more than the amount of power reduction. However, a big reason for solar panels to begin with is to help with reducing pollution, lowering the effect on the power grid and becoming energy dependent.

Some companies recommend a standard cleaning twice a year, while others say yearly. Again, it depends on your solar panel’s output. Let’s look at the seasons to determine the best time.

Summer

The summer heat creates the worst scenario for cleaning solar panels. The intense heat absorbed by the panels make it hard to do anything with them. Water hitting the panels during this time will cool them off and diminish the overall output, not to mention there is a chance of cracking the solar panels because of an intense temperature change.

Fall

The temperature has lowered and it may be a good time to clean your panels. However, this is also when the trees drop their leaves, and there is still pollen in the air. It’s not a bad time to clean your solar panels, but it’s also not the best time.

Winter

Warmer air allows particles to fly further, so as the temperature drops, so does the ability for pollution to take flight. During the winter, the closer you are to pollution epicenters, the more grime your solar panels will receive. This is a constant throughout the winter months, so this is not a good month for cleaning your panels.

Spring

Granted this is the prime season for raised pollen counts, but it is also the best season to clean your solar panels. You want to clean them after the winter months and after some of the pollen have infested your panels, but before the heat arrives.

Pre-cleaning Checklist

Before you start cleaning your solar panels, you need to know what you’re up against. You can’t have the right tools for the job if you’re not sure of the job’s parameters. Consider these questions before you clean your panels:

  1. What type of buildup are you dealing with? Is it just dust, or is there pollen, bird dropping or noticeable grime?
  2. If it is just dust, can you reach the full extent of the solar panels with a water hose? Do you need a ladder to climb up onto the roof?
  3. What is the location of the panels? Are they far enough from the edge so you can maneuver easily without placing yourself in danger.
  4. What is the condition of the roof? Is it too steep to easily grab your footing? Does the roof have weak spots? Is there moss or other slippery obstacles that can hinder your footing?

Asking these basic questions will help you determine if your can do it yourself or if you need to call a contractor to do the job.

Tips for Cleaning your Solar Panels

Before you start cleaning there are a few other things to consider. It’s important to know the when, the how and your expectations after the cleaning process is finished. Here are a few tips to help you get off to the right start.

  • The first thing you should do before cleaning solar panels is to check your current output, and compare it to what the output should be. This will help you gauge the amount of solar output to expect after the cleaning.
  • Pick the right time of day to perform the cleaning. Cooler days are the best, and if possible, try to clean them earlier in the morning or later in the evening when the temperature has faded.
  • Never use soap when cleaning. Regardless of the type of soap, it will leave a residue. When you wash your hands and place them up to your nose you can smell how clean they are, but in reality, if you can smell the soap there’s still some on your hands. 
  • Solar panels should be shut off before you clean them. 
  • Only clean the glass portion of solar panels. Do not wash underneath them, it can damage them.
  • Think safety. If possible, get a long pole and wash your solar panels with a pole extension from the ground. Don’t climb up on the roof unless you absolutely have to.

Cleaning your Solar Panels

You’ve done your research and have determined that your solar panels do need to be cleaned. Here is a step-by-step guide to help you make the most out of your cleaning experience. Let’s make those panels sparkle.

Remove Larger Debris from the Solar Panels

The first step in cleaning solar panels is to remove large debris from them. Use a dry brush to remove leaves, pine needles and other larger objects that have roosted on your panels.

Clean the Solar Panels

Clean the panels with water to remove the light dust and dirt from them. Some regular faucet water can be hard, which means it’ll leave spots when it dries. To help reduce water spots, use deionized water for the cleaning. Professionals use a water deionizer when they clean solar panels, but the machine can be a bit expensive. 

Deionized water is the best thing, but a secondary idea is vinegar. Use one cup of white vinegar per 8 cups of water. Avoid industrial strength vinegar and use those at the 5- to 8-percent level. Vinegar will help break down the hardened water and reduce the number of spots during the drying process.

Use a soft brush and clean each panel thoroughly. Due to the out layer of solar panels, most of the debris should come up rather easily. 

Some think the rain is efficient enough to clean solar panels, and in some cases, it can be. To a point. The rain, if it’s not polluted by dirt or pollution can wash away most of the debris, but it also pools the debris onto the lower panels. Here is sits and reduces the effectives of the lower panels.

This debris may not come easily and you may have to do more of a deep clean to remove it.

Spray the Solar Panels with Water

Rinse the solar panels with the water from your hose. The vinegar will still help protect your panels from spotting. Do not use a high-pressure attachment when spraying the residue from the panels. Some manufacture warranties will be voided if a high-pressure hose is used on their solar panels. Only apply as much water as is necessary to get the job done.

Scrub the Solar Panels

Sticky pollen, sap, and pollution grime can be a bit difficult to remove. It may be tempting to apply a mild soap to the mixture, and as bad of an idea that it is, it may be your only choice.

First, scrub problem areas with a soft sponge or squeegee. Maintain a repetitive motion without applying extra pressure. Push too hard and you may cause the debris to scratch the panels. Deionized water attracts molecules and can help pull the grit and grime from the panels. If you feel that you have to use a mild dish soap to remove the problem, then add it to the water/vinegar mixture and apply it to as limited of an area as possible.

Soap residue not only minimizes the sunlight’s effectiveness on solar panels, but attracts unseen dust molecules. As an added precaution to maximize your cleaning, you can restart the entire process after you’ve applied the soap to remove as much of it as possible from your solar panels.

Monitor Solar Panel Output

Now that your solar panels are clean, it’s important to monitor the output of your solar panels. You checked your panel’s output before you started cleaning, and now you can see if all the hard work paid off. If you’re not happy with the results then you may have to clean them again.

Contact a Solar Panel Professional

If you have tried everything to clean your solar panels and they’re still not producing as much electricity as they normally would, it may be time to call in a professional. Also, if you decided early on that cleaning the panels will require too much time and effort, or you deemed the location of the panels as unsafe, then a contractor is your best choice.Contact Advantage Pro Services to help with all of your roof solar panel needs. Over the past 20 years they’ve become the premiere solar panel cleaning experts for homeowners and businesses alike. With over 13,000 jobs successfully fulfilled we are your number one choice for solar panels, window cleaning and pressure washing. Call us today!!

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