Best Solar Inverters: String vs. Micro vs. Power Optimizers
Choosing your solar panel type and whether you want to lease or buy are typically the biggest decisions you’ll make when evaluating your solar options.
However, another big decision involves the type of inverter you choose to convert the direct current (DC) energy that your panels produce into the alternating current (AC) that your home relies on. The three inverter options – string inverters, microinverters, and power optimizers – all work slightly differently and come with their own distinct pros and cons.
Photo Source: LetsGoSolar.com
How String Inverters Work
Often referred to as a “central” inverter, string inverters are the most commonly used type of inverter. Under this PV setup, your solar panels are wired together though a common “string,” and all of the energy the panels produce is sent to a single inverter that is typically located in your basement, garage, or on the side of your house.
Advantages:
- Easy maintenance that doesn’t require climbing up on your roof.
- Low cost
Disadvantages:
- String inverters will only produce as much energy as the least productive panel
String inverters are ideal for the budget-conscious solar user who has solar panels that are in good working order and unobstructed by shade. Since a PV system tied to a string inverter is only as good as the worst performing panel, a faulty solar panel or a roof with constant areas of shade can significantly affect your solar energy production capabilities.
How Microinverters Work
Microinverters are set up in the opposite manner as a string inverter. Solar PV systems with a microinverter have an individual “micro” inverter attached at the site of each solar panel. Whereas string inverters send energy from every panel to a single inverter, a PV system using microinverters converts the DC solar energy to AC energy on the spot.
Advantages:
- Poor performing panels don’t bring down the production capabilities of the whole PV system.
- Easy to identify when an individual panel is flawed and in need of maintenance or replacement.
Disadvantages:
- A costlier option than string inverters
- Maintenance of microinverters is complicated by the fact that they are located on the roof.
Microinverters are ideal for solar users who have a roof with various slopes or have obstructions, like a chimney, that casts a shadow on portions of the roof.
How Power Optimizers Work
Power optimizers combine many of the primary features of both string inverters and microinverters. Like microinverters, power optimizers are located on the roof alongside of or integrated with each individual solar panel. However, a PV system with a power optimizer still sends power to an accompanying string inverter.
Unlike microinverters that do the DC to AC conversion at the site of the solar panel, power optimizers simply “optimize” DC current before it is sent to the string inverter for conversion into AC current. This leads to a much more efficient current conversion process.
Advantages:
- Offer similar advantages as a microinverter, but typically at a lower price point.
- Microinverters and power optimizers typically come with a 20 to 25-year warranty.
Disadvantages:
- Like a microinverter, maintenance and repair costs are typically going to be high with power optimizers given their rooftop location and constant exposure to the elements.
Power optimizers are a good fit for homeowners who are willing to pay more for making their solar energy system more efficient, but want a slightly more affordable option than a microinverter.
String inverters are the tried and true method for converting solar-generated DC current into AC current, but microinverters and power optimizers (together referred to as module-level power electronics – MLPEs) are swiftly gaining steam in residential solar markets.
For residential solar users, it’s nice to have options, and string inverters and MLPEs each have pros and cons. Be sure to do your research to determine the best fit for you.
