How We Test
We test solar equipment on our own rooftop array and a ground-mounted test bed. Real-world performance data from our monitoring systems, not manufacturer spec sheets.
Scoring Criteria
Every product receives a score from 0 to 10 based on weighted criteria. Here is exactly how we calculate it.
Performance & Efficiency
We measure real-world energy production against rated output over 90+ days. Temperature coefficients, shading performance, and low-light output are tested.
Build Quality & Warranty
We evaluate panel construction, junction box quality, frame durability, and warranty terms. We track manufacturer financial stability because a 25-year warranty means nothing if the company folds.
Value & ROI
We calculate payback period and 25-year ROI using real utility rates. We factor in available incentives, degradation rates, and financing costs.
Installation & Compatibility
We assess mounting compatibility, wiring complexity, monitoring system quality, and installer availability. We note any special tools or skills required.
Tools & Equipment
The tools we use to produce consistent, reproducible results.
- Rooftop and ground-mounted test arrays
- Enphase and SolarEdge monitoring systems
- IV curve tracer for panel characterization
- Pyranometer for irradiance measurement
- 30-year financial modeling calculator
Independence Pledge
- No sponsored rankings. Our scores are never influenced by advertising or affiliate relationships.
- We buy everything ourselves. Products are purchased at retail price with our own funds. No vendor-supplied review units.
- Affiliate transparency. We earn commissions from some links. This funds our testing but never affects our scores. Full disclosure.
- Corrections policy. If we get something wrong, we update the article with a visible correction notice and date.
Update Cadence
Panel reviews include 12 months of production data. Battery reviews are updated with firmware changes. Incentive information is verified monthly.
Every article shows its publish date and last update date. If a review is more than 6 months old without an update, we flag it as potentially outdated.
Our Testing Team
The people behind the scores.
