How big of a system can I have?

It depends on several factors including: the size of your electrical panel, the size of your roof, your annual electric usage and of course your budget. The design of the system is constrained by how much your electrical system can handle based on the National Electrical Code. If you have a good roof to put the panels on, the available square footage is a limit to the size.

In New York you can only put in a system that generates no more than 110% of your annual electrical usage and get incentives from the system from NYSERDA. So, for example, if you use 5,000 kWh per year you can put in about a 4.5kW system. Such a system would take up about 325 sq ft. The shape of the available space makes a difference as to what can actually fit in the space. Figuring this out is all part of the design work that goes into planning a system.