More motivation to let a robot vacuum

To go on a proper energy diet, first you'd have to measure the power consumed around the house, outlet by outlet. Just like counting calories, that would take all the fun out of gobbling up electricity. But if you're really geeked about saving money and greening your home, then you might follow the lead of one Silicon Valley engineer who crusaded around his apartment with the Kill-a-Watt energy meter, measuring the appetite of nearly every appliance.

Eric Boyd calculated that over a year, his refrigerator, desktop PC, and iMac used the most electricity. He estimated that his stove, oven, and air conditioner demanded a bit less energy than the computers. (Government figures, on the other hand, list heating and cooling as the biggest energy gobbler.) The toaster, microwave, washer, and dryer were hungrier for watts than anything else in Boyd's home, but their infrequent use led to low operating costs overall. Lighting didn't cost much because he already used compact fluorescent bulbs instead of ravenous incandescents. And in case you needed more motivation not to clean the floor yourself, his Roomba ate up a piddling 43 cents of his annual electrical bill.

Unfortunately, Boyd concluded that he'd barely notice a dent in his utilities bills if he conscientiously unplugged every gadget from the wall when not in use. But various studies show that standby power drained by those dormant appliances might quietly eat up as much as one-tenth of your energy expenses.