This is the biggest question many people will ask when it comes to installing a PV solar system. Many variables play into the equation, so it’s difficult to give a set answer. However, in Colorado the range is between 3-6 years for a system on a commercial property and 7-11 years for a residential system. Some of the variable affecting price and payback are: Installing a larger system cost less per PV kilowatt; multi-face roofs add complexity and some cost; specialty systems that deal with some shading issues add cost and extend payback time; A ground mount while typically more efficient will cost more than a roof mounted system due to building the structure to mount to; Older homes or commercial properties with electrical systems that do not meet current safety standards may add cost to the installation of a solar system. The best way to determine the ROI (return on investment) is to have a solar PV installer provide an accurate bid to build an appropriately sized system for your address.