by Brook Wilkinson

Yesterday, I discovered that I've been living a lie. I'd read somewhere, long ago, that cell phone chargers leak electricity from outlets even when phones aren't charging. But when I plugged in my new Kill a Watt to check, I found that wasn't so.

The Kill a Watt--which I discovered on Head Butler, the wonderful blog of must-have books, music, and products written by Jesse Kornbluth--is a device that measures how efficient your appliances are. Plug it into a three-prong outlet, and then plug something into the Kill a Watt, and it will calculate how much that item costs to run per hour, day, week, month, or year. (Of course, first you have to set your utility's electric rate, which is quite simple.) The cell phone charger, as I said, costs nothing. A microwave oven costs $1 per year. But a desktop computer--even in sleep mode--costs a whopping $190. Bet that's enough to remind you to turn your computer off tonight.