Mar
First of all the word photovoltaics (PV) has two parts: Photo (the Greek word for light) and Volt (relating to electricity). In that way it really means light-electricity, which is pretty much what it is. PV systems take light energy and convert it into electrical energy.
The most common types of PV systems are based on silicon which, when arranged into a PV cell, creates an electrical current when sunshine hits it. The highest efficiency for silicon is held by monocrystalline silicon, and the lowest by thin films. Monocrystalline silicon is silicon sliced from a single grown crystal, and thin films are PV to which an amorphous film has been applied.
The major drawback to PV-powered homes is the start-up cost. It is really expensive to install a PV-system, but the pay-back is fairly quick depending on the area you are in, the federal and state rebates, and the size of the system itself. PV-systems are expected to have a life span of 25 years or longer. Maintenance costs are fairly low.
Not all PV-systems are the big solar panels on top of roofs. There are a growing number of building-integrated photovoltaic products (BIPV) that are allowing designers to disguise the systems within the roofs. Some are made to look like shingles, and some are made to work with roofing materials. The possibilities are endless!