Solar Panel Cleaning: Should You Hire a Professional Cleaner?

Man cleaning a solar panel on the roof

Solar panel cleaning affects your systems ability ingest sunlight and convert it into usable energy. Anything that blocks the sunlight from reaching the silicon on the solar panels can influence the performance of your system.

Solar panels installed at a steep enough tilt will clean themselves during heavy rainfall, so when do you need to clean your solar panels and how important is it?

Many Australian homeowners wonder how to clean solar panels and its impact on the performance of their solar system. The question that gets asked most is whether or not hiring a solar cleaning service is actually worth it. This article outlines what you need to know.

Is Cleaning Your Solar Panels Worth it?

Dirty solar panels can cause a reduction in power output due to the accumulation of dirt, dust, or other debris on their surface. The extent of power loss can vary depending on the level of dirt and the specific conditions, such as the angle and orientation of the panels, the type of dirt in your location, and the duration of the dirt buildup.

On average, studies have shown that dirty solar panels can experience power losses ranging from 5% to 35%. However, it’s important to note that these figures are general estimates, and the actual power loss can be influenced by several factors.

Regular maintenance and cleaning of solar panels are essential to maximize their efficiency and power output. By keeping the panels clean and free from debris, you can ensure that they operate at their optimal performance level and generate the maximum amount of electricity.

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Solar panels before and after cleaning

Factors Influencing Solar Panel Efficiency?

Environmental conditions play a key role in affecting the efficiency of solar panels. Dust, pollen, bird droppings, and airborne pollutants, being part of our natural environment, may deposit on the solar panels. This can block sunlight and reduce the power output.

Impact of Debris

Dirt and debris accumulated on the surface of solar panels can result in a significant loss in energy production. The particles hinder the sunlight’s penetration, thereby reducing the panel’s energy conversion rate. Thus, periodic cleaning is needed to ensure optimal energy production.

Seasonal Considerations

Different seasons bring varied challenges for solar panel cleaning. Winter snowfall can cover panels completely, while autumn may deposit fallen leaves. Spring pollen is another obstacle for solar panel efficiency. Each season, therefore, mandates a different cleaning approach.

Different environments and locations are subject to worse soiling than others.

What makes solar panels dirty?

Bird Droppings
Although one bird dropping won’t make a huge difference, over time these will build up and can significantly reduce output.
Often rainfall alone won’t be sufficient to clean bird droppings
Dirt Accumulation Around the Frame
Although rainfall will often clean most of the dirt of your solar panels if they are at a 10 degree tilt or more, dirt will often build up around the aluminum frame. This can cause losses and even hotspots to develop.
Debris
If you have nearby trees or are exposed to high winds, then over time you will find that larger debris can become lodged between the panels causing shading and impacting the output of the system.
Fungi, Lichen or Mold
Just as you can get these growths on your roofing sheets or tiles, over time you can expect the same to happen to your solar panels. 
Particulate exhaust or dust
If you are in an industrial area then you may find that nearby factories disseminate byproducts that we fasten to solar panels and become difficult to clean.

When to clean solar panels?

As a rule of thumb, it is recommended to clean solar panels at least once every 2-3 years to maintain their optimal performance. 

The frequency of cleaning residential solar panels can depend on various factors such as your location, weather conditions, and the surrounding environment of your home. 

Cleaning the day-to-day dust off a solar panel usually happens naturally in heavy rainfall if your panels are installed at a tilt, so generally cleaning solar panels is necessary where there is more heavy soiling present.

Signs your solar panels need cleaning?

  • Visual Inspection: If you can see anything that might be obstructing sunlight from reaching your solar panels, or the solar panels are looking discoloured, then usually it’s time to clean the solar panels.
  • Reduced Performance: If you log in to the monitoring system and notice that the system is not performing to expectations (less power than last year, or last month allowing for sunlight variations) then it may be time to call in a solar panel service professional. A Solar Choice inspector 
  • Insect or Pest Activity: If you notice an increased presence of insects or pests around your solar panels, it might be a sign that they are attracted to the accumulated dirt, pollen, or other organic matter on the panels. Cleaning the panels before it’s too late can prevent damage to the solar panels and if necessary bird prevention can be installed.
  • Panels installed flat or less than 5 degrees: Panels installed with minimal tilt will lose the ability of heavy rainfall to effectively wash them. So dirt will accumulate much faster and will require more frequent cleaning.

Keep in mind, always prioritize safety. Cleaning solar panels often involves climbing onto a roof, so it is always recommended to hire a solar panel cleaning service. Be sure to follow all manufacturer instructions for cleaning to avoid damaging your panels.

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What are the costs of solar panel cleaning?

The costs of solar panel maintenance service is around $250-$350 but can vary depending on factors such as system size, complexity, and the need for professional assistance. In metro areas across Australia, the typical price to clean residential solar panels is around $15-$20 per panel.

We have another guide here that covers the average cost of cleaning here

Worker on the roof cleaning solar panels

Why hire a professional solar panel cleaner?

The best way to clean solar panels is by using a solar panel cleaning service as using a professional comes with many benefits. Here are a few:

Insurance Compliance

If your solar panels are insured, there might be specific maintenance requirements you need to meet for your insurance policy. Hiring pressional solar panel cleaners ensures these are met and that your investment is protected.

Preventative Maintenance

Besides cleaning, professionals can also identify potential issues before they turn into costly problems. This might include damage to the panels, faulty wiring, or other technical problems.

Safety

Solar panels are often installed on rooftops, and cleaning them can involve some risk of injury. Solar panel cleaners are trained to handle these situations, and they have the appropriate safety equipment.

Time-Saving

Cleaning solar panels can be a time-consuming task. Hiring a solar panel service near you allows you to spend your time on other important activities while the work is being taken care of.

Longevity

Regular, proper maintenance can extend the lifespan of your solar panels. Solar panel cleaning services know how to clean and maintain panels in a way that prevents damage and helps ensure they’ll last as long as possible.

Expertise

Professional solar panel cleaning services have the knowledge and experience to clean the panels to maximize efficiency. They understand the intricacies involved, like the kind of cleaning agents to use, how much pressure to apply, and other details to avoid damage while maximizing efficiency.

Keep in mind that the necessity and frequency of solar panel cleaning can depend on a variety of factors, including your local climate, angle of the panels, and more. Therefore, it might be beneficial to assess your individual situation and consult with a solar panel expert to decide the best approach.

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How to clean solar panels?

Your solar panel cleaning checklist should include a ladder, roof harness, soft-bristled brush with a long handle, outdoor cleaner, long hose, safety helmet, and gloves. For a sparkling result, mix water with gentle soap or opt for a solar panel-specific cleaner. You can gather the necessary equipment from your local hardware store. For instance, Bunnings solar panel cleaning kits are a simple option or you can assemble your own. We’ve simplified the process with this straightforward step by step guide for your convenience.

Quick Guide On How To Clean Solar Panels

  1. Switch Off Your System: An important Safety precaution is to begin by turning off your solar system at the switchboard, following the provided instructions.
  2. Rinse the Panels: Safely access the roof and rinse the panels to remove loose dirt and grime.
  3. Prepare the Cleaning Solution: Mix water with a mild, soap-like dishwashing liquid or use a solar panel-specific cleaner. Avoid harsh chemicals to prevent damage to the panels.
  4. Apply the Solution: Use a soft cloth or squeegee to gently apply the cleaning mixture. Employ a soft-bristled brush for tackling stubborn spots.
  5. Rinse Thoroughly: With a comprehensive water spray, rinse off all soap and cleaning agents, ensuring no buildup remains around the panel frames.
  6. Dry the Panels: Prevent water spots by drying the panels with a clean, soft cloth.
  7. Inspect: After drying, inspect the panels for any missed hard spots. If soap residue is visible, it should be cleaned off to ensure a pristine finish.

For those considering the DIY route for solar panel cleaning, prioritising safety is essential. It’s crucial to always secure yourself with a harness before beginning any work.

Case Study: Is solar panel cleaning worth it?

If we take a typical residential household in Sydney with a 6.6kW solar system consisting of 20 solar panels on a 1-story roof. We would expect the cost through Solar Choice’s partners to be around $250-$350 to have the solar panels serviced professionally.

In a recent study published by the International Energy Agency, they found that typical dust and dirt can cause output reductions of 3% to 5%. Generally this normal soiling would not justify the cost of cleaning your solar panels. Another study published on Sustainable Energy Research, demonstrated that heavily soiled solar panels could impact performance by up to 60%.

For a typical 6.6kW system in Sydney we know that the daily average production is 23.5kWh per day. Cleaning solar panels that are underperforming by 30% will create an additional 7kWh per day. This would create an additional $44 per month or $528 in the first 6 months.

This assumes that, in this scenario, the owner uses 50% of his solar energy avoiding a 35c per kWh tariff while 50% of the energy is sold back to the grid for a 5c per kWh feed-in rate.

There are plenty of limitations with this generic calculation, so you will need to use some common sense when assessing the state of your solar system and if in doubt you can send some photos to sales@solarchoice.net.au.

FAQs (Frequently Asked Questions)

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Jeff Sykes