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

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. 

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.

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.