Brushing Up On Brushes

Synthetic hard bristles. Effective at lifting dirt? Yes. Safe for the coating? Hardly.

You've seen it advertised here, "Coat-Safe Brushes." Why is this important? Your solar panels need to last and perform well for at least 25+ years, so some thoughtfulness is needed when it comes to long-term maintenance. Similar to our vehicles, if we want them to last, we need to be thoughtful in how we take care of them. For example, you might have heard that it is best to avoid automatic car washes, since the spinning bristles eat away at the coating, causing long-term damage, as can be seen below:

What do solar panels and vehicles have in common? They each have a protective surface coating (for vehicles it's called clearcoat, for solar panels ARC), a coating that needs to be protected so that contamination and oxidation do not set in. This is why solar panels need to be cleaned with the same care as vehicle paint: gently, not with chemicals, not with a pressure washer, not with a harsh scrubber. Once this coating is compromised, it can accelerate the detrimental effects of oxidation.

This is why solar panels need to be cleaned with the same care as vehicle paint, gently

That doesn't seem too complicated - grab your favorite microfiber and detergent, and clean the panels the same way, right? Not quite. First, using detergent is not a good idea around the roof and home. Roof material is not designed to handle detergents, be it tile, shingle, or concrete (Google "cleaning roof with detergent" as a reference). Detergent run-off can also stain a variety of surfaces, in addition to contaminating soil and hurting plants. Second, most panel surfaces are not usually reachable by our hands and arms, and washing panels while kneeling or bending down on an angled roof is simply dangerous.

Which leads us to pole brushes, ubiquitous with solar panel cleaning. Without detergents, microfiber is too soft to remove dirt from the surface, so most pole brushes use bristles. Whether or not the bristles damage the coating depends primarily on three factors: the quality of the bristles, the pressure applied, and the presence or absence of constant water flow. A constant water flow is vital so that dirt and debris can gently wash away without scratching the coating. And the key to a good brush? High-quality (dense) and natural (not synthetic) bristles. This usually means costly brushes, whereas cheaper ones are less dense with harder synthetic bristles, which can easily damage the coating. You can visually see the difference in this comparison:

cheaper brushes are less dense with harder bristles

This highly rated brush on Amazon uses synthetic and hard bristles, which might be ok for regular windows, but can easily scratch the panel coating

In comparison, a high-end brush is natural, soft, and dense, and will be gentle on the surface even after repeated passes. It also costs about 3 times more

How much pressure should be applied? As light as possible, while allowing the water flow to soften up and loosen the dirt layer. This approach requires patience and a gentle approach, taking time from the first panel until the last one. I have observed other cleaners start off steady and slow, and after the first few panels, they're scrubbing at high speed trying to finish the work quickly. I make sure not to rush any job, always being mindful that the panel has a coating that must be protected for longevity. Solar panels should last 25+ years, and the right brushes and cleaning technique goes a long way in ensuring that they perform their highest for the longest time. Interstellar offers the best cleaning service using the best brushes on the market, at the best prices, contact us to find out for yourself.