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Step-by-Step Guide to Buying the Right Light Bulb

LED? CFL? E26? A19? Warm white? Cool daylight? The choices can be daunting

seventeen different kinds of light bulbs

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If you’ve ever gone to a big-box hardware store to get a light bulb, you may have glanced down the vast length of the lighting aisle and decided that it’s not such a bad thing to go to bed at dusk and wake up at dawn. 

But don’t be intimidated by the hundreds of choices you have among the rows and rows of light bulbs. Technology has changed bulbs for the better: They last far longer than they used to, they can produce different intensities of light, and some can even be turned on and off by a cellphone, motion or the sunrise. Finding the right one just takes getting used to a few criteria old bulbs didn’t offer. Buying the wrong one can mean yet another trip to the store — or, worse, a set of bulbs you can’t use.

Types of light bulbs

Not so very long ago, if you wanted a light bulb, you bought an incandescent bulb, the kind Thomas Edison created for commercial consumption. You can still buy old-school incandescent light bulbs, which have a filament whose brightness depends on the amount of power running through it. But now you have other choices:

  • Light-emitting diode (LED) bulbs were once the most expensive choice, but their prices have fallen significantly. You can get some off-brand LEDs with the equivalent brightness of a 60-watt incandescent for $1 or less; name-brand bulbs typically sell for more. LEDs can last about 25,000 hours, compared with about 750 hours for incandescent bulbs.
  • Compact fluorescent lights (CFL), those twisty fluorescent bulbs, are also more energy efficient than incandescent bulbs. They can last about 8,000 hours and cost about $2 to $3 apiece. Because they contain small amounts of mercury, CFLs will need to be recycled. Some stores, such as Home Depot and Lowe’s, will recycle CFLs for free.
  • Halogen lights are very bright bulbs that are typically used for lighting small areas, such as kitchen counters. They tend to last about 2,500 hours, and burn even hotter than incandescent bulbs, so wait for one to cool off before you touch it.

The amount you pay for a single bulb, however, is just part of the cost. You also need to take into account how often you’ll need to replace the bulbs and how much power you’ll use to run the light. According to the Consumer Federation of America, over 10 years the total cost — that’s the cost of the bulb and the power to run it — of using a 60-watt incandescent bulb would add up to about $70. (That cost also includes buying several replacement incandescent bulbs over the decade.) A CFL costs about $20 over the same span of time, and an LED costs an average of $13.70. The average house has more than 20 light bulbs, meaning that switching to LEDs from incandescents could save you about $1,100 over the 10 years, or a bit more than $100 a year.

Bulb brightness

Not so very long ago, your main consideration in buying a light bulb was how many watts you needed: a 100-watt bulb for reading, for example, or a 60-watt bulb for a table lamp.

A watt, however, is a measure of how much energy it takes to power a bulb — not how bright the bulb is. (It’s named after James Watt, inventor of the steam engine.) Many newer bulbs are marked in lumens, which is the amount of light a particular bulb emits, and that’s because most new light bulbs, such as LEDs, use much less power than an incandescent bulb.

For example, a traditional 60-watt incandescent bulb emits 900 lumens of light and uses 60 watts of power. An LED light that emits 900 lumens of light uses just 15 watts of power. Here’s a table of how watts on incandescent bulbs convert to lumens. 

Watts Lumens
40 W 600 lm
60 W 900 lm
75 W 1125 lm
100 W 1500 lm
150 W 2250 lm

Source: RapidTables.com

What kind of warmth?

Old-style incandescent lights had one shade of white, unless you were partial to colored party lights. New bulbs — even incandescents — have a variety of color warmth, which is measured in a scale of 1,000 to 10,000 degrees Kelvin. (It’s named after William Thomson, Lord Kelvin, who discovered absolute zero — the lowest possible temperature.)

According to bulb manufacturer Westinghouse, Kelvin temperatures for commercial and residential lighting applications fall somewhere on a scale from 2000K (warm white) to 6500K (daylight):

  • Bulbs in the 2700K range are warm white, considered cozy and inviting, and are good for living rooms and kitchens.
  • Bulbs in the 3100K to 4500K range are a cool white, sometimes with a tinge of blue. They’re often used for bathrooms, vanities and outdoor lighting.
  • Bulbs in the 5000K range are called “cool daylight,” and are best used for basements, garages and security lighting.  

Location, location, location

Unless you enjoy climbing ladders, you’ll want the longest-lasting bulbs in hard-to-reach places, such as the top of a stairwell. Here again, LEDs would be your first choice. If you decide to use an LED light for that floodlight mounted under the rafters, make sure you choose one that’s made for exterior use.

And there’s no need to be heroic about replacing a light bulb. If you don’t feel confident about climbing up to replace a hard-to-reach bulb, get a relative, neighbor or handyman to do the job for you.


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If your bulb will reside in an enclosed location, such as a hall light with a glass cover that fits flush to the ceiling, or an outdoor light that’s protected from the weather by a glass globe, you’ll need a bulb marked as usable for enclosed fixtures. LEDs and CFLs don’t last long in enclosed fixtures, because the heat buildup will fry some of their components.

If you’re planning on putting a bulb where it may become damp, such as a bathroom or basement, be sure to get a bulb that’s suited for damp locations. Use outdoor damp-rated lights for porch lights that are out of the rain or wind, and also on decks with an overhang that does not allow water to seep through (otherwise you need wet-rated bulbs).

What kind of features?

Traditional light bulbs had one feature: You put it into a socket, flipped a switch, and it produced light. Today, however, you can buy lights that:

  • Dim. Not exactly a new feature, but you can buy dimmable LED and incandescent lights. Most CFL bulbs are not dimmable — and that will be marked on the package.
  • Listen. Some bulbs are now Wi-Fi- or Bluetooth-enabled, meaning you can turn them on and off (or dim them) or even change them to a wide variety of colors with a smartphone or smart speaker.
  • Wake up. Some outdoor lights can now turn off when the sun rises and on when the sun sets.
  • Keep watch. Some bulbs now have motion sensors, which will startle trespassers and wildlife alike.

One final note: Light bulbs, in particular halogen lights, come in a remarkable number of sizes and shapes. Fortunately, the classic pear-shaped, screw-in light bulb we’re all familiar with and you’re most likely replacing is easy to identify on store shelves. On the packaging, look for “E26” or “medium base,” which indicates the bulb will screw into a standard threaded socket, and “A19,” which signals the bulb is the size and shape of a standard bulb. If you are in need of anything other than a standard E26/A19 light bulb and want to save another trip to the bulb aisle, bring the bulb you plan to replace with you to the store. 

John Waggoner covers all things financial for AARP, from budgeting and taxes to retirement planning and Social Security. Previously he was a reporter for Kiplinger's Personal Finance and  USA Today and has written books on investing and the 2008 financial crisis. Waggoner's  USA Today investing column ran in dozens of newspapers for 25 years.