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
My parents were Depression babies (born in 1922).
My parents were frugal New Englanders.
“Turn off the lights” was drilled into us.
Now, of course, I do the math and it still amazes me how many lights in our house it takes to reach 100 watts.
Was having this very conversation with one of my kids just yesterday ~ it was drilled into us. At least those of us who grew up with depression-era grandparents. I don’t even say anything about it anymore, it’s a habit: see a light on that doesn’t need to be … turn it off.
Oft overlooked is the post-depression period of lights out for the war effort
On slow-charge, 110 volt, my car-charger draws less current than the fridge …
Incandescent light bulbs, now widely replaced by LED bulbs, use up a lot of electricity, wastefully perhaps, because heating filaments to the the point where they emit photons takes a lot of energy and is intrinsically wasteful. (More infrared energy coming out than visible light.) Particularly when you have a lot of lights on. Thank TA Edison for that.
A couple of years ago we replaced our old fashioned (new when it came with the house 50 years ag0) boiler which uses hot water circulated through pipes to base-board radiators in every room. Two zones, upstairs & down. Was maybe 80% efficient at converting natural gas to heat, relied on ‘leakage’ of air into the house to burn the gas, exhausted fumes through the chimney. Modern 95%-efficient boilers pull in air through pipes & exhaust fumes through other adjacent pipes. Much cheaper to run. BUT, use the same circulator technology to move the hot water through the house.
A couple of months ago, after getting a huge electricity bill, I realized that the thermostat for downstairs had been left at 65 or 66, and should have been turned down about 5 degrees. I did so, and discovered that the next month’s bill dropped about 30%.
So, if yer electric bills are high, though you have lots of LED bulbs, check the thermostats.
The house we lived in in St. Louis for 35 years had a natural gas boiler and hot water heat circulating through cast iron radiators (the house was built in 1928). The only thing electric about the heating was a tiny motor in the basement that moved the water. I doubt it contributed significantly to our electric bill; it was the gas bill that was affected by the thermostat in our house.
Once, we had a 3-day power outage in the winter. The temperature in the house dropped into the low 50s. My brother and I rigged up a backup power system for the circulating pump that could use the car batteries. Remove a battery and hook it to an inverter that was wired into the motor circuit. A switch was used to isolate that power from the rest of the house and outside so that no repairman would get an electric shock.
Joel:
Pretty ingenious to do such. We had a fire place with a blower which we wold use if we had issues with the furnace. To do what you did, you have to know something.
It wasn’t the gas bill that went up. It was the electric bill. Maybe it was overuse of the microwave or the toaster oven. Right… Or perhaps the few incandescent bulbs that are still in use.
I read an article on electric utilities in 1936 when six cents was considered a reasonable price for a kwh. One utility operator explained his pricing. Back then, women would leave the house, lock the door then put on their gloves. He said that if she noticed a light bulb left on and felt it was worth taking off her gloves, unlocking the door, turning off the light, locking the door again and putting her gloves back on, the price of electricity was too high.
Perhaps the most interesting aspect of this post is that, at least in LED-equipped households, it shouldn’t matter (much) if you turn off lights or leave them on. (Not so with thermostats!)
Don’t tell me to get a programmable thermostate for downstairs. Ordinarily, that area is not used often enough to have heat turned up ‘regularly’.
well, two things
when i moved into an apartment in Portland, after a few months the electric company came out and switched my meter. figured it was broken since i used less than half of what my neighbors used.
on the other hand, one day i came home and found the house suspiciously warm. yelled at my daughter for turning the heat up. and then laughed at myself when i saw my breath condense as i was yelling. [“yelling” is a figure of speech. laughing at yourself is better for children.)
2) still being cheap, i find that not using heat when i don’t need it, and keeping the temperature very low even when i do, i use about ten percent of the fuel that my neighbors use. I do find that electric heaters in a room when needed are cheaper than a whole house furnace that cannot reasonably be turned off when and where not needed. i think much of the heat from a whole house system is lost in the ducts.
i don’t know if ten bulbs use less heat than a refrigerator, but i bet multiplied by 300 million or so, it makes a difference. trouble with the gd refrigerator is you can’t tell how much electricity it is using as it ages, whatever the tag on it in the store said.