When installing a solar panel system, the most common question is: do you need an inverter for solar panels? The answer is—yes, most of the time. But the "why" and "when" depend on your energy system, objectives, and types of appliances you want to power. It's a device that converts direct current (DC) electricity, which is what a solar panel generates, to alternating current (AC) electricity, which the electrical grid uses. Solar panels produce DC power; your. . Rooftop solar power, also known as rooftop photovoltaic (PV) systems, refers to solar panels installed on residential or commercial building rooftops to generate electricity. Inverters come in sizes ranging from 2. 5kVA for residential setups to 40kVA for large-scale systems.