Simpler Solar. Cost and complexity are the two main reasons you don't see a photovoltaic array on every rooftop in America (except in Seattle). Solar in a Box simplifies the installation process and reduces labor costs, says the maker. In addition to a ready-to-go AC solar-panel assembly, the modular kit includes all necessary cables, connectors, and roof mounts. The builder just needs to provide home-run wiring and circuit breakers. (A separate kit has all the materials needed for future expansion.) The price to builders varies from $3.95 to $4.50 per kilowatt. Ready Solar, 877/817-3239, readysolar.com