Solar Panels

The "active ingredient" in almost all home solar electric panels is silicon - a semiconductor that's also used in computers. Silicon-based solar panels are called "photovoltaic" panels, and there are two main types: crystalline and thin film.

Many companies are researching alternatives to photovoltaic panels, but it will be a long time before these technologies are available and a good option for your home.

Crystalline Solar Panels

These "traditional" solar panels can be either monocrystalline or polycrystalline.

Monocrystalline panels are made from a large, single silicon crystal and have a patchwork pattern. Polysilicon panels are made of lots of tiny silicon crystals and have a geometric pattern. While monocrystalline panels are more efficient than polysilicon ones, they are also more expensive.

The efficiency of crystalline panels range from 12% to 20%, and they are almost always the best choice for a home solar system.

Thin Film Solar Panels

Amorphous photovoltaics, or thin film silicon panels cost much less to produce, but they are also much less efficient. The silicon in thin film panels is printed on a flexible backing material. The efficiency of thin film panels ranges between 6% and 10%. Thin film panels take twice as much space to make the same amount of energy as crystalline panels.

Note: "Thin film" is a catch-all phrase and some thin film solar panels aren't silicon based. Some use other semiconductors such as cadmium telluride (CdTe) or copper indium gallium diselenide (CIGS).

BIPV Solar Panels (Solar Roof Shingles)

A twist on thin film solar panels are building integrated photovoltaics (BIPV). These are designed to act like solar roofing shingles. BIPV panels are more expensive and somewhat less efficient than traditional solar panels, but many consumers consider them to be the best-looking option on the market.

People also often talk about solar thermal or concentrating solar. These are both solar hot water technologies and don't make electricity.