If you’re in the lighting business, you probably get asked every now and then whether you should turn the light off every time you leave the room. The answer depends on the type of lamp and how long you’ll be gone.
- Incandescent Lighting – Turn Off! Incandescent lights are the least efficient type of lighting we use and should be always be turned off when not in use. Since 90% of the energy incandescents use is emitted as heat, turning off the lights also keeps a room cooler.
- Halogen Lighting – Turn Off! Though halogens are somewhat more efficient than incandescents, they are far less energy efficient than LEDs or CFLs, the most efficient lights available. Turn them off when you leave the room.
- Compact Fluorescent Lighting (CFL)– About 15 Minutes CFLs use 75% less energy than incandescents and last ten times as long. However, they are more affected by the number of times they are switched on and off, so extend the life of the bulb by switching it on and off less frequently. The U.S. Department of Energy recommends that if you’re gone for 15 minutes or less, leave it on.
- LED Lighting – Turn Off! LEDs are the most energy-efficient. Neither their performance nor their lifespan are affected by turning them on or off. LEDs are often used together with occupancy sensors or daylight sensors so they can turn on and off automatically. LEDs turn on at full brightness almost instantly and with no delay.