The Robservatory

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Shedding some light on the cost of lighting

In our home, our kitchen is lit with eight in-ceiling flood lights. Each uses a 65W incandescent bulb, and it seems to me that at least one of them is burned out at any given point in time.

Frustrated by the never-ending replacement cycle, and aware that there were longer-lived and more-efficeint options out there, I decided to look into replacing the incandescent bulbs with either CFL (fluorescent) or LED lights.

I was curious as to whether CFL or LED would be the better option for us, and how much it would cost to switch, in both the short and long term.

tl;dr summary: If you can afford the up-front costs, switch your lights to CFL or LED now. You will save a lot of money, and spend less time replacing bulbs. Read on for a full cost analysis of my kitchen light replacement project.

At our local Home Depot, I compared the incandescents to the CFL and LED bulbs, and found the following:

BulbCost/bulbEnergy $/yrLife
Philips 65W BL30$2.41$7.831.8
EcoSmart 65W CFL$4.97$1.697.3
Cree 65W BL30 LED$14.97$1.1422.8

Energy cost is based on $0.11 per kilowatt hour, for three hours per day.

(The energy usage cost and life, along with a "light appearance" scale and other useful tidbits, all appear on a newish lighting label that makes it simple to compare multiple lighting options.)

For the eight lights in our kitchen, the costs look like this:

Bulbs (Qty: 8Up frontAnnual
Philips 65W BL30$19.28$62.64
EcoSmart 65W CFL$47.76$13.52
Cree 65W BL30 LED$119.76$9.12

The LED lights' up-front cost is quite high; over double the CFLs, and roughly six times that of the incandescents. But the annual costs are dramatically lower than either, and their lifespan is the longest (by far) of the three options.

Here's how the costs compare for our eight-lamp kitchen, on an annualized basis. The Replace column is a pro-rata share of the replacement costs (i.e. $19.28/1.8 for the incandescents) for each type of lighting.

Annual CostsOperatingReplacementTotal
Philips 65W BL30$62.64$10.71$73.35
EcoSmart 65W CFL$13.52$6.54$20.06
Cree 65W BL30 LED$9.12$5.25$14.37

Using the above figures, it's easy to create a worksheet showing the cumulative cost of each type of lighting (scroll to see all years):

Running CostNormalCFLLED
Year 0$19.28$47.76$119.76
Year 1$92.63$67.82$134.13
Year 2$165.98$87.88$148.51
Year 3$239.33$107.95$162.88
Year 4$312.68$128.01$177.25
Year 5$386.04$148.07$191.62
Year 6$459.39$168.13$206.00
Year 7$532.74$188.20$220.37
Year 8$606.09$208.26$234.74
Year 9$679.44$228.32$249.11
Year 10$752.79$248.38$263.49
Year 11$826.14$268.45$277.86
Year 12$899.49$288.51$292.23
Year 13$972.84$308.57$306.60
Year 14$1,046.20$328.63$320.98
Year 15$1,119.55$348.70$335.35

The two highlighted rows show where the LED lights begin to cost less than the incandescents (year three) and the CFLs (year 13). If you look at year 15, the obvious message is: change your lights. It doesn't matter if to CFL or LED, just get away from incandescent.

Despite the LEDs' very high initial purchase price, their extremely low annual energy cost and long life means that within two years, they would be saving us money over the incandescents.

But as seen in the table, to save the most money, we should switch to CFLs; thirteen years is a long time to pay back the investment in the LEDs. And they're saving money over the incandescents after only one year.

In the end, though, I chose to go with the LEDs…not because I honestly expect to save money by using them for over 13 years, but because…

  • Unlike CFLs, LEDs are mercury free. If you have a burned out or broken CFL, you can't just toss it in the trash; there are ways you must recycle them. LEDs have no mercury.
  • I find the color tone of most CFLs to be unpleasant. They seem to have a blueish tint, and just aren't as warm as incandescents or LEDs.
  • Instant-on CFLs aren't as instant as incandescent or LED lights. I like that when I flip the switch, I immediately get the full effect of the light.

So for those reasons, I went with the LEDs. Once installed at home, I found that they're slightly brighter than the incandescents that they replaced, which is a good thing—they're not harshly bright, just brighter. (There were also "daylight" color LEDs available, but they were over $20 a bulb, and that math didn't work quite as well for me.)

If you're contemplating switching out your incandescents, the math shows you really should do so. Note that all figures are based on using a light three hours a day; if you use yours less than that, the savings will be lower. If it's a light that's on a lot, though, you'll save even more.

We've switched to LEDs in our outside lights (which are on about six hours a day), my office (easily 10 hours a day), and now the kitchen (four to five hours a day). We'll slowly migrate the rest of our lights, probably as each breaks, because I like the thought of saving money and not replacing a light bulb for the next 22+ years.

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