by Jessica Miller (Emery Street) | This column provides tips on reducing waste while saving money.

Is it better to turn lights off whenever you leave a room, or to leave them on if you know you will come back shortly? Energy.gov has some answers. They take into consideration the type of light bulbs you use and their operating life, which decreases every time it is switched on and off. Here is a very brief summary. Visit their page for detailed explanations.

1. Incandescent lights should be turned off whenever they are not needed
2. It is best to turn halogens off whenever they are not needed.
3. The operating life of a light emitting diode (LED) is unaffected by turning it on and off. Therefore LEDs have an advantage when used in conjunction with occupancy sensors or daylight sensors that rely on on-off operation.
4. Since they are already very efficient, the cost effectiveness of turning off to conserve energy is a bit more complicated. A general rule-of-thumb is this:
   • If you will be out of a room for 15 minutes or less, leave it on.
   • If you will be out of a room for more than 15 minutes, turn it off.