The economics of lighting

I grew up with the admonition that you always turn off the lights if you’re the last to leave the room. Or “close the lights,” as my grandma used to say. But home lighting technology has evolved considerably over the past couple of decades.

1. Does it save money to turn out the lights when you leave the room?
2. Does it shorten the life of the bulb by turning it off and on more frequently?

If you have LED lighting, the answers are (1) not enough to notice and (2) not at all.

A little more detail, courtesy of the NYT:

1. “You could have a dozen of LED bulbs going 24/7, and they would still consume less energy than what a typical fridge uses in a day,”

2. “The technology that makes LEDs glow is completely different than that of traditional incandescent bulbs, and LEDs—even smart ones—aren’t physically stressed being turned on and off in the way that traditional bulbs are. As the DOE notes, turning an LED bulb on and off doesn’t affect its lifespan.

“If you’re talking about compact fluorescent light bulbs (CFLs), like what you might have in an office building or a basement, “the operating life of CFLs is more affected by the number of times they are switched on and off,” according to the DOE, which recommends using a 15-minute rule. If you’re going to return to the room within 15 minutes, leave the light on. Longer than that, switch it off.”

Of course, this is just about economics. Interior lights account for tens of thousands of bird deaths every year when they crash into windows of illuminated rooms. At least close the curtains or blinds after sundown, please.

You don’t need to turn off the lights