Photos: Measuring home energy use in dollars and trees

London design firm DIY Kyoto dreamed up this Wattson device. Like the Onzo, its aesthetics might get a nod from the likes of Apple's Steve Jobs. Digital readouts spell out the watts and British pounds being spent.

With an additional sensor, it can also describe the use of renewable sources of energy. The recyclable plastic appliance consumes 5 watts and keeps data for 28 days. It costs 150 euros, and the Wattson isn't available outside of Europe.

Photo by DIY Kyoto

Caption by Elsa Wenzel