Solar Panel Cleaning in Hilo, HI

Solar Panel Cleaning in Hilo, Hawaii

This Hilo home had two separate solar systems on the same red corrugated metal roof:

• A large flat-mounted photovoltaic array spanning most of the roof
• A tilted solar thermal collector unit used for hot water

Both had accumulated a heavy layer of dark brownish-red organic buildup across the glass surfaces. In Hilo’s climate, that kind of contamination builds up faster than most homeowners expect. The combination of frequent rain, high humidity, and warm temperatures creates near-ideal conditions for algae and organic growth to establish on any flat or low-angle glass surface — and solar panels sit at exactly the angle where that growth accumulates and stays.

What Dirty Solar Panels Actually Cost You

A solar panel covered in algae and grime is not just an aesthetic problem. The glass surface is what allows sunlight to reach the cells underneath, and anything sitting on top of it reduces how much light gets through.

The buildup on these panels before we started was significant:

• Several panels in the photovoltaic array were almost entirely obscured by dark reddish-brown organic matter
• The solar thermal collectors had a thick coating of the same residue across both glass surfaces
• The contamination had built up to the point where the glass was no longer reflective at all

In Hilo, where overcast days already limit available sunlight, a heavily soiled panel array is working at a fraction of its potential output. Cleaning is the most straightforward way to recover that lost performance without any additional hardware or system changes.

How We Cleaned the Panels

The two systems required slightly different approaches:

Photovoltaic panels

• Cleaned using a soft wash method — no abrasive tools or high-pressure spray directly on the glass
• High pressure on solar panel glass can damage the anti-reflective coating manufacturers apply to the surface
• The cleaning process lifted the algae and organic buildup fully without scratching or leaving streaks

Solar thermal collectors

• Treated separately given their different surface angle and tilted rack mounting
• Full glass surface cleaned without applying pressure that could stress the collector frame or connections
• Both collector panels restored to clean glass

The red corrugated metal roof around both systems was unaffected throughout. All runoff was directed away from the panels and off the roof edge.

The Difference After Cleaning

The contrast on this job was easy to see:

• Photovoltaic panels went from a dark brownish-red opacity to fully reflective dark blue glass
• Solar thermal collectors were restored to clear glass across both panels
• The full array looked the way it did when it was first installed

If your solar panels in Hilo have visible buildup, discoloration, or a surface that no longer looks reflective and clear, regular cleaning is the most direct way to keep your system performing the way it was installed to.

One thing worth knowing: Hilo’s climate means this is not a once-and-done situation. Organic growth comes back, and staying ahead of it with periodic cleaning keeps the buildup from reaching the level seen on these panels before we started.

Need Your Solar Panels Cleaned in Hilo?

Property Wash in Paradise serves Hilo and the surrounding East Hawaii area with professional solar panel cleaning for both photovoltaic and solar thermal systems. If your panels have visible buildup or you are not sure when they were last cleaned, we will take a look and give you a straight quote.

Learn more about our solar panel cleaning service.

Get a Free Quote

Or call us directly: 808-825-6280