Start with the roof
Roof condition
If the roof will need replacement soon, it may make sense to handle that before installing solar.
Roof material
Asphalt shingle, metal, rubber, flat roofing, and other materials can require different mounting methods and affect installation cost.
Usable space
Vents, chimneys, setbacks, dormers, and roof geometry reduce the area available for panels.
How much sunlight does the roof get?
Shade is one of the biggest site-specific factors. Look at trees, nearby buildings, chimneys, roof obstructions, seasonal shade, and which roof sections receive the most sun.
A south-facing roof can be favorable in much of the United States, but east- and west-facing roofs can also work well. Actual production matters more than labeling a roof direction good or bad.
Does the electrical setup work?
A solar installer should evaluate the main electrical panel, service capacity, meter location, available equipment space, wiring and conduit paths, and whether electrical upgrades may be required. These details affect both feasibility and project cost.
Is your electricity usage high enough?
A technically excellent roof does not automatically make solar financially worthwhile. Solar generally has more potential value when the home uses a meaningful amount of electricity and the system can offset electricity that would otherwise be purchased from the utility.
Solar may deserve extra scrutiny if
- Heavy shade covers most usable roof space.
- The roof needs replacement soon.
- Very little roof area is available.
- Electrical upgrades add substantial cost.
- Electricity usage is unusually low.
- You expect major changes to the home or roof soon.
The real answer comes from the site design
A good solar proposal should show the usable roof area, system size, expected annual production, major equipment, and the assumptions behind the estimate.