We have two small arrays, 12 panels of PV (electric panels) and 16 solar thermal for hot water. Both provide hot water / electricity to our jail. They are roof mounted. Recently one of our electric utilities proposed investment options in a solar farm, this will reduce electric bills, depending on how many panels you purchase. They site the panels on their property, operate and are responsible for them. The cost savings over time is good especially since it protects you from future rate increases. I recommend seriously considering options like this from a long term return and community investment perspective. Our hot water install is fairly complex but seems to work well. Between conservation and alt energy options our utility bills have been the same for a decade despite rate increases and building expansions!