A solar installer will usually design the solar PV system based on an individual home's annual energy usage. However, trying to cover your entire roof with PV may not work and may not even be required. Often only a part of the roof can be used effectively, because of roof-fragmentation and orientation. Our (SmartZeroHome.com) intelligent design generator gives the design specs for your home, including the best PV size (not the maximum) that should be installed on your roof, so that you get the maximum output from the PV and don't overspend.
Following are the main considerations when planning to install a solar PV system on your roof: