Sources behind every claim.
We'd rather lose a sale than make a claim we can't back up. Below is every primary source we cite — NREL field data, Princeton research, the Insurance Information Institute, the EIA, and manufacturer documentation. Click any link to read the original.
Production Loss & Soiling Research
Why we claim 5–15% annual loss for typical U.S. systems, higher in pollen and agricultural zones.
- NREL — Soiling Losses Quantitative Study (2024)
National Renewable Energy Laboratory
Annual soiling losses across U.S. PV fleets — median ~5%, with regional variation up to 15%+.
- NREL — Addressing Soiling on PV Modules
NREL Research Hub
Field methodology and cleaning-recovery measurements across multiple climates.
- IEA-PVPS — Soiling Losses Impact on PV Performance
International Energy Agency, PV Power Systems Programme
Agricultural soiling rates regularly exceeding 15% annually without intervention.
- Princeton — Regular Panel Cleaning & Air Quality (2021)
Princeton Environment in the Half Century
Regular cleaning + air-quality improvements raise PV output, especially in high-pollution / low-rain regions.
Rain Cannot Clean Pollen
Why we tell visitors that rain alone is not enough — backed by NREL field research.
- NREL — Rain Not Enough to Wash Pollen from Solar Panels (2023)
NREL News Program
Direct NREL release stating rain alone is insufficient to remove pollen, requiring scheduled cleaning.
- Renewable Energy World — NREL Pollen Study Summary
Renewable Energy World
Independent reporting on the 2023 NREL pollen findings: >15% peak losses during pollen season.
Wisconsin State Capitol Solar Array
Verification of our most-cited customer outcome — the 2009 installation we cleaned in 2025.
- Renew Wisconsin — Solar Panels Rise to Capitol Heights
Renew Wisconsin
Confirms install date (2009), 48-panel count, ~9,600 sq ft installation, MGE-owned. The +16.7% production lift after our cleaning is our own measured data — see /our-work for the irradiance readings.
Insurance, Warranty & Wear-and-Tear
Why a paper trail of professional cleanings protects your homeowner / commercial policy and warranty.
- Insurance Information Institute — Are Solar Panels Covered by Homeowners Insurance?
III.org
Standard HO-3 form explicitly excludes wear-and-tear, deterioration, and neglect.
- Insurance Information Institute — ISO HO-3 Sample Policy
III.org (PDF)
The actual policy form language used by most U.S. insurers.
- NAIC — Homeowners Insurance Topics
National Association of Insurance Commissioners
Industry-level confirmation of policy-form prevalence and exclusions.
Cleaning Method, Brushes & Deionized Water
Why we use soft rotary brushes + deionized water — backed by manufacturer documentation.
- LG Solar — Official Cleaning Guidance
LG.com
LG officially recommends deionized water + non-abrasive brush; advises against tap water, abrasives, and cleaning agents.
- Enphase — Solar Panel Cleaning Guide
Enphase Energy
Industry-standard soft-brush / gentle-rinse protocol.
Local Wisconsin & Electric-Rate Data
Why we use $0.16/kWh and warn about hard-water mineral deposits in the Madison area.
- U.S. EIA — Wisconsin Residential Electricity Profile
U.S. Energy Information Administration
Wisconsin residential average ~$0.16/kWh (used in our $80–$250/yr soiling-loss math).
- Madison Metropolitan Sewerage District — Water Hardness
madsewer.org
Confirms hard water in the Madison area — the mineral source for the white spotting we remove with deionized rinse.
- NREL — PV Degradation Rates Review (1,900-system meta-study)
NREL
Median panel degradation of ~0.5%/year (used to distinguish slow degradation from sudden soiling losses).
Have a research question we didn't answer?
Text Marquis directly. He'll send you the relevant document with the specific page number or table reference.