Estimated ranges for residential solar inverter replacement span from about $1,250 to $6,100, depending on inverter type and installation complexity. When Do Inverters Actually Fail? According to the National Renewable Energy Laboratory (NREL), inverter failure rates average 10-15% within the first 5 years and. The cost of replacing a solar PV inverter can vary widely, and it's important to understand the range you might be looking at. On the lower end, you might find some basic models for as little as $300. Type of Inverter String inverters are the most affordable.