A: Complex roof lines reduce the number of panels you can fit on a roof. Almost all solar installers today use a software package called Aurora that calculates how many panels can fit on a roof using satellite data on the angle, shade and orientation of the roof. I have found it to be very accurate. If your roof cannot fit enough panels to cut your carbon footprint to zero, I suggest looking at community solar options. There are several companies in MA that offer this. They build large solar-panel array in big fields in MA and sell you the net-metering credits at a discount of usually 10% (one offers 12.5%) to the utility price of electricity. These net metering credits appear on your electric bill. This is a very good option if your roof is not suitable for solar panels.