With a string inverter there is a single point of failure. If the string inverter fails, the entire array is offline. However, with a microinverter each individual PV module has its own dedicated inverter. If the microinverter (or the associated PV module) should fail. only that PV module is offline while the remainder of the system continues to operate.​
Enphase microinverters have a publicly stated defect rate of 0.05%, which equates to 1 in 2000. Given that the Enphase defect rate is better than most string inverters, this results in a PV installation with higher reliability and a higher overall system uptime over the life of the array.
Additionally, Enphase microinverters have an estimated useful life of more than 25 years, compared with string inverters that typically last around 10 years.