Cleaning 101 - What you need to know

People don't give much thought about cleaning, but they should. For example, how many times have you used a cleaning product that was wildly effective, only to find out later it was actually harmful (eg. TCE, Tricolsan, Teflon, etc). Or what about those 5-star rated Amazon scrubbers that make cleaning showers and bathtubs super easy? Those same scrubbers strip off the protective glaze layer and cause long term damage. Automatic car washes and pressure sprayers for the car? Super convenient, yet terrible for the vehicle's clearcoat.

Consistent among these scenarios is the balance of convenience, effectiveness, and long-term effects. We almost always prioritize convenience, without giving much thought to the long-term effects. This is why fast-food restaurants, automatic car washes, and various chemicals are so popular. For the long-term though, more thought is needed, especially for something we keep more than 10 years, which includes our health, our vehicles, and yes, our solar panels.

For the long term, more thought is needed

What has any of this got to do with solar panel cleaning? The same balance applies, it is no different than other cleanings. Want convenience? Go with stiff bristles, pressure washers, and chemicals. Super convenient and effective. Long-term though? Terrible. Why? Because what's convenient strips off the protective coating that each panel has, a coating that protects against long-term oxidation, among other things. Oxidation is the leading cause of efficiency loss over time with solar panels. (Each solar panel manufacturer has their own implementation of this proprietary coating, typically called ARC, or Anti-Reflective Coating, although it could be called by other names. The purpose of this coating can serve multiple beneficial properties).

Close-up of a 15 year-old panel: this is not dirt on the panel, since it was just cleaned, rather we see varying stages of oxidation, the most severe at the edges (red arrows). The scientific reason why this happens is the degradation of the EVA (Ethylene Vinyl Acetate) encapsulant material used to seal the solar cells, leading to the formation of unsaturated hydrocarbons and carbonyl groups, which appears as yellowing or browning discoloration (haze). In plain English, oxidation and the resulting haze blocks light and reduces efficiency. Regular, gentle cleaning can minimize this.

If you want your solar panels to last and be effective for as long as possible, first, choose a cleaner that cares about this. This means someone who cares about the brushes and bristles used, realizing that softer bristles and gentle pressure preserves the surface coating and minimizes oxidation. Being mindful of gentle cleaning also means quick and easy methods are avoided, such as harsh pressure washers, chemicals, and cleaning machines that use rotating bristles. At Interstellar, we pride ourselves in treating your panels like our own, keeping the long-term view front and center of everything we do.

Boar's Hair is both dense and extremely soft and gentle. It's also expensive, most cleaners forgo this brush head and go for the cheaper and harder synthetic bristles.