When you are looking into putting solar on your home, these are the things you should look out for:
Production in kWh (Killowatt hours), Value of the Production and Utility and Solar Rate Comparison.
Production in kWh has these main components:
Size of the system in kW. Basically how big the system is.
Amount of sunlight in that location.
Shading. Could be from trees or other roofs.
Direction of the roof. The roof is in the general vicinity of the South, so the roof should face South.
Tilt of the roof. A 30 degree tilt is optimal for maximum exposure to the Sun.
Once you have the amount that solar PV system will produce you multiply that by the amount the Utility Company charges for electricity (per kWh) and then compare it the solar rate (in a free solar lease deal) or calculate how much money you save by offsetting your regular usage (if you purchased the system).
Then there are other solar incentives, including: SRECs and tax incentives.