It’s that time of year, again! The sun is out in Western Washington, the wind is blowing, and pollen is in the air. If your panels are starting to look a little yellow, now is the perfect time to do a little spring cleaning.
We often get asked how often solar panels should be cleaned. In the Pacific Northwest, our spring rains generally do a great job of keeping solar panels dust-free; it’s that sticky annual pollen accumulation that’ll determine whether cleaning is worth doing and when, as that’s going to vary greatly depending on where you are. Some system owners find that they can go 5+ years without breaking out the scrub brush, whereas others require annual or biennial cleaning.
Is pollen going to significantly impact solar production? Yes and no. A light dusting spread evenly across the surface will have a negligible impact on any given day due to the light-diffusing nature of the glass. However, as pollen starts to accumulate along the lower edge of the frame, it can begin to creep up over the bottom row of cells on each panel, shading those cells and impacting production.
As the saying goes, “An ounce of prevention is worth a pound of cure.” We recommend keeping a casual eye on it, and if you notice any buildup occurring, work out a cleaning schedule that fits you and your system.
DIY or Hire a Pro?
If breaking out the brush, hose, and bucket doesn’t remotely appeal to you, that’s okay! Some systems are multiple stories high or difficult for a homeowner to access. If you’d rather hire someone to do it for you, give us a call at 360-746-0859 or send us an email and we’ll provide you with a recommendation for someone in Whatcom, Skagit, Island, San Juan, or Snohomish County who can take this task off your hands.
If DIY is your cup of tea, read on.
What equipment do I need?
- Gloves to prevent leaving fingerprints or marks on the glass
- Bucket or tub for water
- Gentle window scrubber with an extension — we like this one from Amazon
- Optional: biodegradable, PH neutral soap/glass cleaner
What’s the process?
Wash your panels in the morning or on an overcast day when the sun isn’t strongly hitting the array and the panels are cooler. At Western Solar, we like to clean our own solar panels when it’s raining out! This saves water, prevents thermal shock to the panel, and also prevents evaporation from leaving you with filmy/soapy panels.
Before you start, gently whisk any debris off the surface with a dry cloth or soft brush. If there’s any caked on material such as dirt or bird droppings, remove it with a soft bristle brush or nylon scraper, spraying with a glass cleaner if needed to help loosen; never use a metal scraper as you will scratch the glass.
To wash, spray the panels with water for an initial soak. Saturate the window scrubber with water and extend to reach each solar panel. If needed, a small amount of biodegradable soap can be used to assist in loosening any dirt or pollen. Follow up with a few rounds of rinse sprays to ensure no residue remains, if using soap. For large arrays, wash in sections to avoid evaporation before you have a chance to rinse.
A few other guidelines to note…
- Avoid metal tools such as blades, knives, steel wool, and other abrasive materials. These can damage the glass.
- Do not use high-pressure washers, abrasive brushes, powders, polishers, sodium hydroxide, benzene, nitro-thinners, acidic or alkaline solutions which can damage the anti-reflective coating on the glass and void the warranty.
- Do not wash in hot temperatures.
- Products like Rain-X should never be used on your solar panels.
- If roof access is required, use caution and proper fall protection.
But seriously, how often is washing necessary?
Here in Western Washington, solar panels typically don’t need to be washed more than once every three or four years. That said, every site is different. If your panels are near a dusty gravel road, large field that is regularly mowed, or trees that release a lot of pollen, then cleaning more often may be worth your time.
At Western Solar, we tend to ignore our own advice of washing every few years and opt to clean the panels on our own homes every year. We geek out on optimizing our systems’ generation and curb appeal. Whether you prefer your panels to be clean enough to eat off of or are fine with letting them go several years between cleanings, rest assured that we are here to share some insight whenever it’s time for your roof’s next solar bath!