A 13 kilowatt (kW) residential solar system is the size of installation you are seeking if want you are trying to drive roughly 16,250-20,250 kWh of electricity per year, varying by location and other factors. At Solerus Energy, we carry some of the best residential systems from great brands like SolarWorld. These systems will come with about 50 to 54 panels occupying about 1,000 to 1,080 square feet of roof space. Of course, you receive more than solar panels. When you order a residential system from Solerus Energy, you will get all the supplies you need for mounting and connecting — right down to the grounding lugs.