Choosing the Right Solar Inverter

This guide will help you to choose the best solar inverter for your project. Use this handy reference table to compare the facts. Quickly see the difference in features, performance, warranty and more. Make an informed decision so you know what you are buying. However, these products are ever-changing, with new models or capabilities being added all the time. We'll do our best to keep you up to date with the industry.

TYPE	STRING	STRING + OPTIMIZER	MICRO-INVERTER	HYBRID
DESCRIPTION	Most common and economical option, works great in direct sun.	Add device to back of each panel to "optimize" performance. Each panel operates independently.	Add device to back of each panel to "optimize" performance AND convert from DC to AC power.	String or micro-inverter that works gird-tied or off-grid; Connects solar + optional backup battery to the house.
GRID-TIED	Yes	Yes	Yes	Yes
OFF-GRID	No	No	No	Yes
BATTERY READY	No	No	No	Yes
RAPID ROOF SHUTDOWN	Optional	Integrated	Integrated	Optional or Integrated
PERFORMANCE IN DIRECT SUN	Up to 98% Efficiency	about 2% more	about 2% more	Varies
SHADE MANAGEMENT	Each string	Each panel	Each panel	Varies
PANEL OUTAGE	Affected string non-operational	Each panel operates independently	Each panel operates independently	Varies
MONITORING	Whole system or each string	Each panel	Each panel	Varies
WARRANTY STANDARD	10 years	12 years	10 to 25 years	5 to 25 years, varies by model
WARRANTY EXTENDED	20 years	25 years	N/A	20 years
COST	Most economical	Add 6% to 10% to system cost	Add 6% to 10% to system cost	Add 10% to 25% to system cost
COMMON BRANDS	SMA Fronius Delta	SolarEdge Tigo Energy SMA Fronius Delta	Enphase Energy APSystems Chilicon	Enphase IQ8 Generac PWRcell Outback Power Panasonic EverVolt Schneider Electric SolarEdge Energy Hub Sol-Ark
WIRING CONCEPT	Panel output cables are wired together to form a string, up to a dozen or so panels. Inverter has input for 2 to 4 strings. The inverter then combines the output and converts to AC power connected to the electrical box.	Panel output cables are wired to a small optimizer device mounted to the back of each panel. The optimizer's are then connected together to form a string, usually 8 to 15 panels. Inverter has input for 2 to 4 strings. The inverter then combines the output and converts to AC power connected to the electrical box.	Panel output cables are wired to a small micro-inverter mounted to the back of each panel. The micros are then connected together to form an AC circuit, with up to 11 to 16 panels. Each AC branch circuit can then be combined, or wired to it's own circuit breaker connected to the electrical box.	Varies by model. Similar to String or string + optimizer or micro-nverters wiring.

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What to know about solar inverters

There are FOUR basic types of solar inverter: String, String + Optimizer, Micro-inverter, and Hybrid.

A grid-tied, string inverter is the most economical approach. Works just fine in direct Sun when shade is not an issue. Multiple strings, or groups of panels, are wired together, and then connected to the inverter. Each string operates independently. The string inverter may need replacement in 15 to 20 years. Ideal for ground-mounted systems or buildings where rooftop shutdown is not required.

A string inverter with Optimizers has a small device added to the back of each panel to "optimize" performance. Each panel operates independently, it can be monitored, and includes rooftop shutdown capability. Optimizers help minimize shade losses and improve overall performance.

Micro-inverters also adds a device to back of each panel to "optimize" performance AND convert from DC to AC power. Each panel operates independently, it can be monitored and includes rooftop shutdown capability. Micro-inverters help minimize shade losses and improve overall performance. The smaller electronics have a longer lifespan, and a brand like Enphase has a 25 year warranty.

Finally, a Hybrid inverter can work both on-grid, or off-grid with optional batteries. The solar panels and storage batteries are connected in one unit. The hybrid inverter also has an internal power transfer switch to deliver power during an outage. Some customers buy a hybrid inverter to be battery-ready and future-proof the system in anticipation that battery prices will decrease over time. Can add rooftop shutdown or optimizers as needed. Some hybrid inverters even let you connect a fuel generator as another power source to charge your batteries and power your home or business.

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The value of good design

Most of the solar kits include an up-front design in the price. We want to make sure you get the right kit, with the right parts, for your project. The design covers topics like the power consumption, system sizing, the electrical connection and the structural mounting. Once the design is complete and the order placed, we will prepare a custom permit plan blueprint for the project. You you can provide the plan to the local building authority and utility for net metering approval. This value-added service is unique to SunWatts. The solar design can be ordered separately to get the project started. Then you will get credit for the design fee with solar kits that are 5kW size or larger.

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