For a homeowner, it’s a simple question. But in order to answer the question accurately, solar installers need to make a number of assumptions -- as well as gather some pretty detailed information from a homeowner. Often, by the time these data gathering questions are answered, the homeowner is even more confused.

The ideal system size that a homeowner really needs is bounded by two parameters. First, the number of panels that will physically fit on the roof -- taking into account applicable setbacks, wiring issues, shading, structural requirements and aesthetics. And second, the size of the current (or projected) electric bill (only the utility will benefit if the resulting electric bill is negative). Naturally, a third parameter — the homeowner’s budget — is almost always a factor.

Of course, a lot of number crunching goes on behind the scenes as a good installer determines the energy output, annual savings, and financing options for the customer. And tradeoffs are usually offered between higher efficiency/more expensive panels and inverters, and lower efficiency more affordable equipment. Please Listen Up to this week's Solar Energy Show as we go through a simple three step process to determine how many solar panels a homeowner needs: first, determine how many panels fit on the roof; second, determine how many panels it will take to zero out the electric bill; and third, find a trustworthy solar contractor with fair pricing.