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Home Solar Photovoltaic Systems

Solar-powered electricity is known as photovoltaic electricity and is produced by the reaction of silicon wafers to sunlight. Sales of photovoltaic (PV) systems are increasing at more than 25 percent annually both because their price has been falling and because electricity costs are rising.

A PV system consists of solar collectors, an inverter to convert direct current from the collectors to alternating current, and either batteries for electricity storage or a net-metering connection to the utility.

Net metering uses two meters to track power coming into the home from the utility, and out to the utility from the PV system. You’ll usually get utility credit, not cash, from the kilowatt-hours your PV system feeds back to the electric grid.

Photovoltaic electricity, at about 20¢ per kilowatt-hour, is still more expensive than utility-provided electricity in most parts of the U.S. While it makes sense for many families to invest in PV power, you should first make sure that your home is a model of energy efficiency in other ways. You should confirm, for example, that all your major appliances such as heating and cooling systems bear the Energy Star® label, and that you have installed the maximum amount of insulation in your attic and walls.

Your opportunity to use PV power depends on the characteristics of your climate, homesite, and roof. The direction that your PV system faces is critical to its performance. Ideally it should face the southern sky, but east and west facing roofs may also be acceptable in some climates. Flat roofs work well for PV systems also. PV systems may also be ground-mounted or mounted on large awnings or carports.

Our publication Field Guide to Photovoltaic Systemscontains more information on buying a photovoltaic system. See our Bookstore for more ways to reduce energy costs.