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Frequently Asked Questions

What makes a property a good location for solar panels? A good solar location has a south-facing roof with minimal shading, adequate structural capacity for panel and racking weight, remaining roof life of at least 15 years, and a utility that offers favorable net metering or export compensation. NREL’s PVWatts calculator allows homeowners to model their specific location’s solar resource and expected production.

How much sun does a property need for solar to make financial sense? Properties with at least 4 peak sun hours per day — most of the contiguous United States — can support financially viable solar installations. The Southwest averages 5.5–7.5 peak sun hours, the Southeast 4.5–6 hours, and the Northeast 3.5–4.5 hours. NREL’s National Solar Radiation Database maps solar resource availability by location.

Can north-facing roofs support solar installations? North-facing roof sections produce 30–40 percent less annual energy than equivalent south-facing sections and are rarely financially optimal for solar installation. Homes with insufficient south-facing roof area should evaluate east-west splits, ground-mount alternatives, or whether the available roof area can still support a financially viable system given the reduced production.

Does shading disqualify a property from solar? Shading of 20 percent or more annually on the primary installation area significantly reduces the financial viability of solar. Modern module-level power electronics (microinverters or power optimizers) mitigate string-level shading losses, but shading exceeding 30 percent on most of the available roof area typically warrants considering ground-mount or alternative siting.

Further Reading from Authoritative Sources