How Much Can You Save By Replacing Your Light Bulbs?

If you’re trying to cut costs on energy, one common suggestion is to use more energy efficient lighting by replacing your light bulbs. People understand that Compact Fluorescent Lights (CFLs) and Light Emitting Diode (LED) bulbs use less energy than incandescent lights, but they’re also more expensive.

How much money do you actually save with fluorescents and LEDs? Is it enough to justify the higher costs of the bulbs? Or does the additional cost outweigh the savings you get?

The Cost of Lighting your House

The US Department of energy estimates that about 5% of your energy costs go to lighting. On the grand scheme of things, that’s significantly less than the 17% that goes toward heating water, or the 48% that goes toward heating and cooling your home.

Since it only takes one money-conscious person to change a lightbulb, though, lighting is an area where most of us feel pretty qualified to take charge of our lighting expense.

So let’s make some assumptions: Let’s assume that the cost of energy is 12.93 cents per kilowatt hour, the national average for residential usage in August 2015 according to the US Energy Information Administration.

Let’s do a little math. (Or you can just skip to the bold for the bottom line)

Now, let’s assume the average light bulb in your home holds a 100 watt incandescent bulb that burns 3 hours per day.

3 hours X 365 days X 100 watts = 100,905 watt hours per year

Converting to kilo watt hours (KWH), Electrical usage is measured in KWH.

100,905 / 1000 = 109.5 KWH per year

109.5 KWH *0.1293 =$14.16

The average annual energy cost for a 100 watt incandescent bulb is $14.16 per year.

I won’t do the math again, but the average annual energy cost for a 60 watt incandescent is $8.50. For 40 watt bulbs, the annual cost is $5.66.

The Cost of Lighting Your Home with CFL Bulbs.

Now, let’s assume that you replace your 100 watt incandescent lights with 9 watt fluorescents.

The average annual energy cost for a 23 watt fluorescent bulb is $3.26, $10.91 less than the cost of using the 100 watt incandescent.

Other common wattages include the 13 watt CFL ($1.84 per year) and 9 watt CFL ($1.27 per year), If you replace 100 watt incandescent bulbs with 9 watt CFLs, your annual savings moves up to $12.89

The Cost of Lighting Your Home with LED Bulbs

So let’s assume you want to look at the most energy efficient bulbs, and go with 5 watt LED lights instead.

The average annual energy cost for a 5 watt LED bulb is $0.71, $13.45 less than the cost of using the 100 watt incandescent, and $0.56 less than the cost of a 9 watt fluorescent.

Other common wattages for LEDs are 14 watts ($1.98 per year) and 9 watt ($1.27 per year).

Replacing Your Light Bulbs

So, what about light bulbs themselves? Aren’t incandescent lights cheaper?

Yes and no.

An individual incandescent light bulb is cheap, less than a dollar.

However, it burns out quickly. According to the US Department of Energy, CFL bulb lasts about 10 times as long as the average incandescent. An LED lasts 20-15 times longer.

Are LEDs 20-25 times more expensive than incandescent bulbs? Are CFLs 10 times more expensive? Is it just too expensive to try replacing the light bulbs?

Not anymore. You can pick up LEDs as low as $2 on a good sale, but the least expensive options usually run in the $4-5 per bulb range. You can generally find CFLs in the $1.50-$2 per bulb range, or cheaper if you shop the sales and go with multipacks.

One change we made was replacing 150 watt outdoor flood lights with 15 watt LED flood lights. These are we leave on all night and let motion sensors turn them on and off as people (or in our case, deer) trigger them. Switching these continued to give us considerable savings while providing plenty of security. We’ve made changes just about everywhere, though, often with little or no compromise in light quality.

Bottom Line on Lighting Costs: Incandescent Bulbs Are Really Expensive

Between replacement and operation costs, incandescent light bulbs are the most expensive option by far, even if you normally use relatively low wattage options. You might pay $1 to buy one, but you might have to replace it 20 times before you’d have to replace an LED, or 10 times more than a CFL. Over a 10 year period, you might spend $20 for incandescent lights, versus $4 or $5 for CFLs or LEDS. And that’s before including the extra energy you spend by not replacing your light bulbs.

If you’re still using incandescent bulbs, seriously think about replacing your light bulbs in the fixtures and lamps you use the most.

As for CFLs versus LEDs, not everyone loves CFLs. The light quality can be harsh, and CFL bulbs have to be disposed of carefully due to the mercury content. That’s okay. If you look carefully, you can find LED bulbs that may cost the same or less than an equivalent CFL bulb once you consider the difference in life span and operating cost.You may have to experiment a little to find the best lighting option for particular situations. You may like CFLs better in certain situations than you like LEDs, and vice versa.

It only takes one person to change your light bulbs. The energy savings will quickly make up for the cost of replacing your light bulbs.

Image courtesy of sippakorn at

Part of Frugal Fridays at Aspired Living & Annie and Everything

16 Responses to “How Much Can You Save By Replacing Your Light Bulbs?”
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