Two houses on the same street can have very different solar potential. The direction your roof faces, its pitch, and shade from trees, chimneys or neighboring buildings all affect how much electricity panels can produce over a year.

In much of the country, roof sections facing south tend to produce the most, while east and west faces can still work well. Shade is often the bigger issue. Even partial shade during the middle of the day can cut output, and trees that look harmless in winter may block a lot of light once they leaf out.

A good installer will use satellite imagery, shade analysis tools or an on-site visit to estimate production for your specific roof. Ask to see that estimate in writing and how it was calculated. If the numbers depend on trimming or removing trees, find out who is responsible for that work and what it might cost before you sign.