When selecting a 20kw solar inverter, prioritize models with high peak efficiency (above 98%), strong thermal management, and compatibility with your existing or planned solar array and grid requirements. The following table summarizes key features of top-rated 20. Choosing the right 20 kW solar inverter is crucial for maximizing your solar energy system's efficiency, reliability, and lifespan. These inverters can handle a range of power sources from 20,000 watts to 24,999 watts. For most commercial installations or large residential systems, a three-phase string inverter.