What is a microinverter?

Microinverters are small inverters that convert the output from a single solar panel into electricity you can use in your home. When sunlight hits a solar panel, the panel creates DC (direct current) power. Because the electric grid uses AC (alternating current) power, and solar panels can’t create AC power on their own, a device called an inverter is needed to make the switch.

How are microinverters different than central inverters?

In a home solar system using a standard central inverter, solar panels are typically connected together in a series that produces one burst of power. This electricity is sent into the central inverter, which is often installed inside a garage. Microinverters, on the other hand, are much smaller, and designed to be attached to each solar panel on your roof. The current from each panel is directly converted and sent into your home.

Advantages of microinverters

A big advantage of using microinverters is that if one panel becomes shaded, or blocked by snow or leaves, it won’t affect the rest of the array. In a setup where solar panels are attached in a series, the panels act like one unit; if one panel performs 10% less efficiently, they all will. If there’s a manufacturing defect in one panel, or anything else goes wrong as the panels age, the whole array will be affected. Microinverters eliminate this problem because every solar panel is independent, and if there’s any small problem with one of them, the rest of the panels will still continue to pump out power normally.

Central or “string” inverters also come in limited power ratings. Solar arrays come in all sizes, based on the needs of your unique house. Because the size of central inverters is limited, you may end up having to pay for one that’s much bigger than you actually need. Microinverters can be customized to the exact number of solar panels that you have.

Microinverters also take less space; since they’re up on the roof, you won’t have to find room in your garage. Central inverters sometimes require cooling fans that can be noisy. Because microinverters run at lower power points than central inverters, they also have the advantage of requiring less additional equipment. Cooling fans can be eliminated, large transformers are no longer necessary, and other parts can be smaller.

Microinverters are also considered more reliable than central inverters. They have longer warranties (usually 15-25 years, versus 5-10 years for central inverters). Because they handle less power and produce less heat, they can last longer. Because they help solar panels work independently, it’s easy to see if a solar panel isn’t performing correctly and repair or replace it to keep the whole system working at its best.

Cost of microinverters

Because each microinverter has to duplicate the parts inside a single large central inverter, it’s a little more expensive to buy a set of them. The price has gotten cheaper over the last few years, and the efficiency has also improved. New technology came out in 2011 that can power two panels at once, rather than just one, which also helped bring the price down.

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