The SunPower panels will be equipped with microinverters, which are about the same size as the black connector boxes seen here. That's a technology that wasn't used heavily during the Solar Decathlon competition two years ago. Inverters are needed with solar electric panels to convert the direct current they generate into household alternating current. Right now, most installations use a few large inverters to do the job. But in the past two years, a number of companies have developed microinverters that convert DC to AC on each individual panel. This has historically added cost to the overall system but microinverters offer some advantages and better efficiency, say proponents. Each panel can be monitored for performance and shading on one panel won't decrease the output of panels wired to it, as happens with centralized inverters. For homeowners, microinverters means that homes can add just a few panels at a time as they are wired individually.