Labour: Having people climb around roofs is dangerous, and people with dangerous work expect higher compensation. Inverter: Cost of materials, assembly, and QA

Labour: Having people climb around roofs is dangerous, and people with dangerous work expect higher compensation. Inverter: Cost of materials, assembly, and QA. You want good stuff for the amount of current passing through. Cabling: Cabling is mostly materials in cost. Conductive metals are expensive. Metal Mounting: It's heavy, and requires lots of raw material and expensive equipment to create it.