1. A method comprising: receiving, at a computing device from a user, a design specification for a solar power installation project, the design specification identifying a total number of solar panel modules to be installed at a site and placement of each solar panel module at the site; loading, by the computing device, possible string lengths for the solar panel modules, a string length being deemed possible if the string length has a string voltage potential that falls within an allowable range of input voltages for one or more inverters available for installation at the site; and evaluating, by the computing device, whether the design specification is feasible in view of the possible string lengths.