Domestic Solar Panels
Domestic solar panels might never need cleaning.
Design factors in most conditions and installation take care of the rest. For instance, rain is nature’s way of keeping the panels clean. The angle at which each cell is installed ensures the majority of dirt washes away with the rainwater.
In States with very little rainfall, homeowners still find that the occasional downpour is enough to keep their solar system clean.
Properties close to heavy industry, agriculture, factories, or free-ways attract more dirt and heavier pollution. Again, unless you live in a state renowned for drought conditions, rainfall is most likely sufficient to keep solar panels clean.
Commercial Solar Panels
Commercial solar panels should be cleaned regularly. By their nature, they are in areas where dirt and pollution are higher.
Potential financial losses are greater the bigger the system gets.
Loss of production affects the length of payback time, expected savings on utility bills, and any potential earnings.
Most commercial set-ups include a maintenance plan; it is an annual equipment and performance check that often includes a full system wash.
There are solar panel cleaning services available if your installer doesn’t provide them.
How to Know When it’s Time to Clean Solar Panels
There are three reliable methods:
- Physically go outside and check. If safe, use a ladder and look for signs of build-up or dried on bird droppings.
- Check your monitoring system. Are your panels performing as expected for the time of year, or has there been a drop in production? It could be a warning sign that it’s time to give them a clean.
- Subscribe to a monitoring service offered by your installation company at the time of set up. For a small fee, payable monthly or upfront, they continue to monitor your system to ensure it is performing to its full capacity at all times. Not only does this pick up on issues before they occur, but it also saves you money and extends the lifespan of your PV system.
For commercial solar arrays, all of the above criteria apply but it is also worthwhile scheduling a regular annual or bi-annual clean, depending on your business and the location of the panels.
How to Clean Solar Panels
Let’s assume that you are confident in tackling the job yourself and have a safe structure from which you can securely reach the panels. If your panels affect production levels or have unsightly stains on them, it’s time to wash them.
Note: Before performing any maintenance task yourself, ensure you read the manufacturer’s installation, maintenance, and safety documentation. Doing these tasks yourself could cause personal injury, harm, or loss. Avoid using harsh chemicals, industrial-grade cleaning agents, or sharp instruments as they may void your warranty.
Time of Day
Solar panels inherently get hot. Leave any cleaning until the sun goes down, or better still, early in the morning before the brightest sun is overhead.
Follow the Guidelines
Refer to the instruction manual left by your installer, or head online to find their recommendations.
They might have a particular trick up their sleeve to return the panels to their best. More importantly, there may be products or methods that you should avoid for fear of invalidating any warranty.
NO Pressure Washing
The temptation might be great, but high-pressured water creates micro-cracks that significantly affect yield; Avoid do so at all costs.
Just Water
Tap water from a bucket or hose is best and usually sufficient enough to do the trick. Some professionals use deionized water although it isn’t essential.
If you choose to use detergent, a squirt of dish soap is sufficient. Harsher chemicals react with the panels and harm them.
Granted, car wash soap could be considered a better alternative as dish soap does contain micro-abrasives.
Non-Abrasive Cloths
A sponge or cloth is the only other piece of equipment you need to gently wipe away dirt. Instead of over-reaching, use a mop to reach the furthest points.
Mop heads get into all corners, including the bottom of the frame where debris sometimes collects, left behind by the rain.
Don’t apply too much pressure; Use gentle rubs in a circular motion.
Is it Worth Cleaning Solar Panels?
Domestic solar energy systems perform better when they’re clean, but only by a small margin.
If a typical 5kw system generates more power than an average household uses, is cleaning the panels worth the time and expense?
A 2% yield improvement compared with before and after washing panels equates to an overall saving of around $20.
It’s for you to decide whether it is worth the trade-off, especially if you’re paying a professional more than the actual savings.
Figures inflate when dealing with a commercial system. Studies show that energy yields significantly improve, by up to 10%, based on a large system cleaned 12-months previously.
The earning and potential savings increase accordingly, while payback time decreases.
