A solar inverter makes up about 10% of the total cost of your solar energy system. The size of your system, the type of inverter, and the efficiency rating affect your final cost. If you add solar panels to an existing system, you can increase your solar electricity generation, extend the life of your installation, and create further savings on utility energy costs. Most solar panel contractors. Premium Technology Justifies Higher Costs: While SolarEdge systems cost 20-35% more than basic string inverters ($5,500-$9,000 vs $3,000-$5,000 for residential installations), the module-level optimization delivers 15-25% higher energy production, typically paying for the premium within 2-3 years. The size of your solar system (measured in kilowatts, or kW) directly impacts the size—and, therefore, the cost—of your inverter. Think of it like this: a small apartment needs a smaller AC unit than a large house. The same principle applies here. String inverter systems cost less up front, but systems using microinverters last. In a solar installation quote, "adders" refer to the costs for equipment, labor, or features beyond the basic panel and standard inverter setup.