If you're one of the "every little bit counts"-types of green dwellers, you've probably gotten into the habit of shutting off your lights when you leave a room. But in the back of your head, you're reminded of that old wives' tale: It takes more energy to power up the lights again than you're saving by shutting them off. Those old wives are sometimes right, though. Depending on how long you're stepping out, it might save watts to keep the lights on, and the magic number depends on the type of bulb.
Of course, if you're leaving the house for an 8-hour workday, you should definitely be turning off unnecessary lights—for both mother nature's sake and for the sake of your wallet.
But if you want to know if it's a good idea to shut off your CFL bulb when you leave the room for just a few minutes, it gets trickier. Luckily, Reader's Digest's green guide spelled it out for us:
- INCANDESCENT BULBS: Shut these power suckers off if you're leaving a room for anything more than 5 seconds.
- CFL BULBS: Shut them off if you're leaving a room for more than 15 minutes.
So if your living room light fixture is stocked with CFLs, it's not worthwhile to flip the lights off for your short bathroom break. But if you're rocking incandescent bulbs, or have been eating plenty of fiber, you might want to hit the switch.