Test Drive a Solar Array's Wattage Before You Build With RoofRay Google Maps CalculatorSThinking of camping out at Ikea once they start selling those solar panels? While you're waiting, RoofRay will help you plan exactly how many SUNGLYÄSS units you'll need, and how much you'll save. Draw the shape of a prospective solar array on Google Maps' satellite image of your roof, enter its slope angle, and watch RoofRay calculate how much DC juice your panels will generate. It doesn't take into account exactly what kind of panels you'll be using, so of course it's an estimate, but an interesting tool for getting the general idea of how much you could knock off the electric bill. See it in action in a demo video below. [RoofRay via Treehugger]