Solar
A module is a sheet of glass angled at the sky.
Everything in the air lands on it, and rain smears most of it rather than removing it. On monitored systems we record production seven days either side of a clean so the result is measured, not claimed.
Soiling by season
What lands on a Cape Fear array
Sample loss ranges observed across coastal residential systems. Your array will differ with pitch, orientation, tree cover and distance from open water, which is exactly why we measure rather than quote an average.
| Season | Main driver | Sample output loss | Notes |
|---|---|---|---|
| Late winter | Salt film and winter grit | 2 to 4 percent | Low sun angle means the absolute kWh loss is small |
| Spring, February to May | Longleaf and loblolly pine pollen | 5 to 9 percent | The heaviest soiling window of the Cape Fear year |
| Summer | Salt aerosol and dust | 3 to 6 percent | Frequent afternoon rain rinses part of it away |
| Autumn | Oak tannin, leaf litter, bird deposit | 3 to 7 percent | Bird deposit causes localised hot spots, not just loss |
All figures on this page are sample values for a demo website, not performance guarantees.
Method
Deionised water, soft brush, no detergent
Detergent leaves a residue film that attracts soil faster than the panel had before, and the surfactants in household cleaners can attack the anti-reflective coating on the cover glass. Most manufacturer O and M documents prohibit both detergents and high pressure. Our method is what those documents specify.
Baseline the monitoring
Seven days of production recorded before we touch the array, so the comparison afterwards means something.
Work cold
Before 10 am or after 5 pm. Spraying water onto glass at 140 degrees F risks thermal shock to the module.
Rinse, brush, rinse
A pre-rinse floats the grit off before any brush touches the glass. The brush lifts bonded film. A deionised final rinse dries without spotting.
Inspect the hardware
Rails, clamps, conduit and the junction box. Coastal fixings corrode and it is far cheaper to catch that inside a warranty period.
Report
Photographs, any cracked cells or delamination found, and the production comparison once seven days have passed.
Hot spots
Why bird deposit is worse than dust
Even soiling across a whole module costs you a percentage of output and nothing more. Localised soiling is a different problem. A single opaque deposit, typically bird droppings or a leaf that has bonded on, shades one cell while the rest of the string keeps pushing current through it.
That shaded cell stops generating and starts dissipating. The bypass diodes in the junction box exist to limit this, but repeated cycling in a marine environment is exactly the condition that eventually fails them. The discolouration you sometimes see on an older panel corner is the record of that happening.
So the useful rule for a coastal array is not "clean it when output drops". It is "clear localised deposit early, and clean on a schedule that matches the pollen and salt calendar".
Solar questions
What owners actually ask
Send us your manufacturer O and M document and we will confirm compatibility before booking.
It depends entirely on the site. On coastal arrays we typically see mid single-digit percentage recovery after a spring pollen season, and less after a clean winter. Any figure quoted before we see your data is a sample, not a promise.
Most manufacturers require soft brush and clean water and prohibit detergents and high pressure, which is exactly the method we use. Send us your O&M document and we will confirm before booking.
Most Wilmington arrays do well on twice a year, timed after pine pollen ends in May and again in late autumn. Arrays within a mile of open water often justify three.
Yes, and they are cheaper per panel because access is simple.
Solar array
Measured before, measured after.
On monitored systems the production comparison comes as standard. On unmonitored systems we photograph the array instead and tell you honestly what we can and cannot prove.
Insured and IWCA. Certificates issued to your property manager on request.