Solar Panel Cleaning: Should You Hire a Professional Cleaner?

Solar panels 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 tilt will clean themselves during heavy rainfall, so when do you need to clean your solar panels and how important is it? This article outlines what you need to know.

Understanding the Need for Solar Panel Cleaning

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, 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.

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.

Main causes of solar panel soiling?

Different environments and locations are subject to worse soiling than others. Here are some of the common things that can influence your solar panel efficiency over time:

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.

How often should you get your solar panels cleaned?

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

As a rule of thumb, it is recommended to clean solar panels once every couple of years to maintain their optimal performance. 

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.

Here are a few things to look out for that mean its time to get your solar panels cleaned

• 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 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 professional. Be sure to follow all manufacturer instructions for cleaning to avoid damaging your panels.

What are the costs of solar panel cleaning?

The costs of solar panel maintenance can vary depending on factors such as system size, complexity, and the need for professional assistance. In metro areas across Australia, the typical cost to clean residential solar panels is around $10 to $15 per panel.

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

Should I hire a professional solar panel cleaner?

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

Expertise

Professional solar panel cleaners have the knowledge and experience to clean the panels properly. 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.

Safety

Solar panels are often installed on rooftops, and cleaning them can involve some risk of injury. Professionals 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 professional 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. Professionals know how to clean and maintain panels in a way that prevents damage and helps ensure they’ll last as long as possible.

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.

Insurance Compliance

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

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.

How to clean solar panels

While we always advocate for professional cleaning which usually only costs around $200 depending on how many solar panels you have and how easy it is to access your roof. If you’re keen to roll up your sleeves, safety always comes first so don’t forget to use a harness.

Start by buying the required equipment from your local hardware store, bunnings is a good place to start for solar panel cleaning kits. You will need a ladder, roof harness, soft-bristled brush with a long handle, outdoor cleaner, a long hose, safety hat and gloves. For a sparkling finish, a blend of water and gentle soap or a solar panel-specific cleaner is your go-to. To make things easier, we’ve put together a quick guide for you:

1. First follow the instructions at your switchboard to turn off your solar system
2. After safely getting onto the roof, give your panels a good rinse to dislodge any loose grime.
3. Put together a simple cleaning mix using water and a mild soap-like dishwashing liquid, or opt for a cleaner designed for solar panels. Avoid using any harsh chemicals or cleaning agents which may damage your solar panels.
4. Gently apply the cleaning solution using a soft cloth or a squeegee. For any stubborn spots, try using a soft-bristled brush
5. Rinse off all the soap and cleaning agents with a thorough water spray ensuring there is no build up around the aluminium framing.
6. Finally, dry the panels with a clean, soft cloth to avoid water spots.
7. Check to see if all of the hard spots are cleaned off, if the panels dry before rinsing you may see a residue from the soap that should be cleaned off.

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 $200 to have the panels professionally cleaned.

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)