What they assumed about production
Two quotes that list the same number of panels can still forecast very different energy production. Ask for the production estimate and the assumptions behind it: local weather data, shading analysis, tilt and azimuth, and system losses factored into the model. Check whether the company used on-site measurements or just satellite estimates. Production predictions are the key driver of future value because they affect how much grid electricity you'll replace. Remember that estimates vary by roof and by company modeling practices, so compare apples to apples when possible.
Installer quality and the national vs local tradeoff
National firms and local installers each have tradeoffs. Larger brands like Sunrun, Palmetto Solar, or Freedom Forever can offer scale, published processes, and bundled financing or monitoring tools. Local companies often know municipal permitting, have hands-on crews nearby, and may be easier to reach for service. Important things to compare: whether the installer uses subcontractors, who handles permits and inspections, how service calls are routed, and whether workmanship guarantees are in writing. Don’t assume a national brand means better installation — vet crew experience, references, and responsiveness for every quote.
How the contract and financing shape real cost
Sticker price misses financing costs, contract terms, and long-term buyout clauses. If a company offers loans, leases, or power-purchase agreements, get the complete financing disclosure and a plain summary of monthly costs, total paid over time, and any early-termination or transfer terms. Look for itemized fees (interconnection, meter swap, roof work) and who pays for permit delays or change orders. These details often explain why two similar-looking quotes lead to very different out-of-pocket and long-term costs. Always treat financing as a major comparison factor tied to your location, credit, and utility rates.
Warranties, monitoring, and serviceability
Ask what the warranty covers and who handles claims: the manufacturer, the installer, or a third party. Avoid relying on verbal promises — request written warranty details. Compare monitoring platforms, what’s included at no extra charge, and whether remote production data is part of the contract. Also ask about routine maintenance expectations, roof penetrations, and how quickly the company responds to performance issues. Warranty length alone isn’t enough; also consider how easy it is to get repairs done in your area.