No single answer applies in every case. But a solar rebate and other incentives can always reduce the cost. Your price depends on a number of factors, including whether your home is under construction and whether photovoltaic is integrated into the roof or mounted on top of an existing roof. The price also depends on the photovoltaic system rating, manufacturer, retailer, and installer.
The size of your system may be the most significant factor in any measurement of costs versus benefits. Small, single-PV-panel systems with built-in inverters that produce about 75 watts may cost around $900 installed, or $12 per watt. These small systems offset only a small fraction of your electricity bill. A 2-kilowatt system that meets nearly all the needs of a very energy efficient home could cost $16,000 to $20,000 installed, or $8 to $10 per watt. At the high end, a 5-kilowatt system that completely meets the energy needs of many conventional homes can cost $30,000 to $40,000 installed, or $6 to $8 per watt. These prices are rough estimates; your costs depend on your system’s configuration, your equipment options, and other factors. Your local photovoltaic providers can give you more accurate estimates or bids.