Obsessively turning off household lights to save money is a habit most of us have, but it turns out it’s not really the money-saving power move we think it is. Here’s why you can stop.
It Saves Money, But LEDs Make It Hardly Worth It
Let us be perfectly clear right out of the gate: If you turn off a device in your home that uses electricity, no matter how big or small the device, you will, of course, save money. It idoesn’t matter if the device is a giant power-hungry gaming PC or a tiny night light in the bathroom—if it isn’t using electricity, then naturally, you aren’t paying for that electricity.
When it comes to serious energy savings, however, LEDs completely changed the game. The efficiency of LED lighting compared to traditional incandescent lighting is staggering.
Back in the day, it made sense to turn the lights off when you left the room. Our parents weren’t out of line to tell us to turn the lights off and sigh when we didn’t. The total wattage of all the incandescent lights in a big room could easily exceed the wattage of a desktop computer under load, and there was an associated penalty on your electric bill and your wallet.
LED lights use a small fraction of the energy traditional incandescent bulbs do, though. Such a small fraction, in fact, that—depending on the bulbs in question—you can power anywhere from half a dozen to a dozen LED bulbs with the power required by the incandescent bulb you’re replacing.
The (Lack of) Savings by the Numbers
It helps to look at some actual concrete numbers to put it all in perspective. Let’s say, for the sake of example, that there are ten light bulbs on the ground floor of your home that you would like to keep on—for security, you just like the warm lighting in the evening, or whatever the reason might be. And let’s say you leave them on for 5 hours every night.
Suppose you have ten traditional 60w incandescent bulbs. They consume a total of 600w per hour or 0.6 kWh. You can multiply that by the cost your local utility charges for kWh, but the U.S. national average is $0.12 per kWh, so we’ll use that.
Each evening when you leave those ten bulbs on after work, it costs you $0.36. Per month, it’s $10.96, and per year it’s $131.49. That’s not early retirement money, but it’s certainly a chunk of money that could have been spent on something else like 6-12 months of your favorite streaming service, or your heat bill in the winter, or any number of things.
Now let’s say you have ten 60w-equivalent LED bulbs used under the same conditions—5 hours per day in the evening after work. Most 60w-equivalent bulbs use between 8-9w of energy, so we’ll use 8.5w for our calculations.
So now your per-hour energy use isn’t 600w, it’s 85w. At the U.S. national average energy cost, running those ten bulbs for 5 hours after work costs you $0.05 per day, $1.55 per month, and only $18.62 per year.
In fact, to get even close to the energy expense of leaving the ten incandescent bulbs on in the evening, you’d need to leave roughly seventy equivalent LED bulbs on. For many people, that would mean turning every single light on their house on, including the porch lights, garage lights, and even the attic lights, too.
Use Your Lights Guilt Free
The point of this exercise isn’t to encourage you to be wasteful for the sake of being wasteful. Efficient LEDs or not, there’s no reason to leave attic or closet lights on 24/7.
But with the efficiency of LED bulbs, flipping lights off in a room you’ll be returning to shortly or not leaving accent lights on around your house when you really love the cozy vibe they provide just doesn’t make a lot of sense. Don’t fret about wasting too much power setting up smart lights to make winter feel less gloomy or otherwise enjoying your lights.
The cost to run a 60w-equivalent LED bulb is $0.001 per hour—a tenth of a cent. At that price point, you’re talking 1,000 hours of operation to hit one dollar.
And hey, if you want to enjoy your lights extra guilt-free, unplug your lesser-used electronics or put them on a power strip you can flip off when you’re not using them
While you should leave frequently used items and crucial things like your internet modem and router plugged in, you’ll save way more power per year by unplugging unused electronics than you will beating yourself up for leaving the kitchen lights on.
I used a Kill-a-Watt meter to check the “phantom” idle load on all my smart TVs, for example, and found that the individual TVs used around 18W of idle power. That’s two LED bulbs worth of power, 24/7, except completely wasted because it’s just powering a TV that isn’t even turned on.
So if you want to take a “there’s no such thing as a free lunch” approach to your lights, unplug your unused electronics and put that energy towards your super-efficient LED bulbs guilt-free.
