Compare energy, not panel count
Put each proposal on the same annual-kWh basis and review shade, orientation, weather, degradation and clipping assumptions.
Use an independent production model as a reasonableness check, while recognizing that it is not a performance guarantee.
Separate price from financing
Compare cash price, financed price, dealer fees, interest, term and total payments. A low monthly payment can hide a longer or more expensive obligation.
For leases or power-purchase agreements, review escalators, transfer terms, production guarantees and end-of-term options.
Map every responsibility
Identify roof work, structural review, electrical upgrades, permits, interconnection, monitoring and incentive paperwork.
Separate equipment warranties from workmanship, roof-penetration and production commitments.
Sources and further reading
Questions or corrections? Contact the editorial team.
