Copper Dusk

It's nine at night. The kettle and the well pump kick in together, the lights flicker, and you start wondering whether the battery will last until morning. Copper Dusk sizes the power system for a house that isn't connected to anything. Tell it what you plug in, where the house stands and when you live there, and it works out the battery, the inverter, the solar array and the generator — then shows you, hour by hour, whether the lights stay on. Start with your appliances. Pick a fridge, a pump or a kettle from the catalog, or add your own, then run a finger along a 24-hour ribbon to paint the hours each one runs. Every appliance gets its own breaker: flip it down and watch the whole system shrink. It's the quickest way to find out what that water heater really costs you. Then the sun. Choose your city or type in your latitude, pick a climate, and see what your roof makes in every month…