The surface area required for a solar PV system is about 18-20 sq./ft. per solar panel. Depending on the size system you require assume 60-80sq/ft. for every 1000 watts (or 1kWatt) of solar PV required to meet your needs. The biggest variable in the amount of space needed is the type of panel you use for your system installation. Panels vary in efficiency and wattage by manufacturer and manufacturing method. The “average” residential home, with a 6-8kw system on a South facing roof would require about 500-650 sq ft of available (preferably unshaded) roof space.