Purchasing used solar panels can be a great way to save money when installing a solar system in your home or business. The life span of a solar panel is currently unknown—many of the first solar panels are still in operation. But most experts believe that quality solar panels will last more than 80 years. Additionally, recycling old photovoltaic cells will keep their valuable parts and resources from wasting away in landfills—an added environmental bonus.

Although older photovoltaics are still functional, newer panels are technologically advanced and often more efficient. Newer panels produce more wattage with less surface area, so if you have a limited amount of space, it may be wise to spring for a newer model. It can also be difficult to combine many different types of used panels into a large solar array—so be sure that you are dealing with a seller that can provide enough panels of the same type to suit your needs. Panels built before 2005 are often inefficient in shaded areas, a problem that can be addressed by situating older panels in locations that are unobstructed by vegetation or buildings.

Don’t shy away from damaged solar panels. They can be easily and cheaply fixed by a trained professional. Cracked glass, broken frames, condensation under the glass and broken or loose connections are common problems that can often be repaired. Some panels gain a brown tint with age, a condition that does not affect their power-producing ability.

Although there are many websites that offer used solar panels, it is important to test the voltage of used panels, in-person if possible. Be sure to bring along a voltmeter to test the circuit of each panel before purchase. Apply the leads of the voltmeter to the positive and negative ends of the photovoltaic terminal. The meter should read close to 12 volts on a healthy 12 volt panel. Panels that are designed to function in a set of 4 should read between 4 and 5 volts each.

Any way you look at it, finding a cheap solar alternative saves you money and allows you to take advantage of your state's solar incentives and rebates.