How to Buy a Better Light Bulb

By Jennifer Tuohy

It might be time to retire that old joke “How many (fill-in-stereotype-to-be-mocked-here) does it take to screw in a light bulb?” Because light bulbs have got a whole lot more complicated in recent years. These days, it requires substantial acumen to buy the right bulb, especially if you are looking to buy the most energy-efficient model.

The battle for eco-friendly supremacy between Light Emitting Diodes (LEDs) and Compact Fluorescents (CFLs) bulbs is largely over (plummeting prices and expanding models have given the more energy-efficient, longer-lasting LEDs the clear edge over CFLs, which still contain mercury). The result of the revolution however, is that navigating the light bulb aisle at the hardware store can be something of an overwhelming experience.

As this infographic illustrates, due to low energy use and incredible lifespan (up to 50,000 hours compared to 8,000 for CFL and 1,200 for incandescent), LEDs have emerged as the clear eco-conscious choice in the light bulb space. Graphic by Jennifer Tuohy.

Brighter, greener and smarter bulbs are great for the planet, but this innovation means there is more choice than ever before; consequently there are more decisions to make when you go to buy a bulb. Do you want Wi-Fi connected and color changing? Flat bulbs or three-way brightness? Dimmable and remote controlled? And these all come after you’ve decided if your bulb will give off “warm” or “cool” light, be indoors or outdoors, and candle or bulb shaped.

Here to help you navigate the vast light bulb aisle is a shatterproof guide to picking the perfect bulb:

Select a Shape
Not every bulb fits into every fixture, so before you decide on the shape check which base is required for your fixture. There are three standard bases, Edison screw (the most common), bayonet (for smaller bulbs and popular in Europe), and GU—more of a specialty bulb fitting. The next step is selecting the right shape for your needs. Shape is particularly important when considering the amount of light you’ll get and how far it will reach.

Spots: Also called reflectors, spots concentrate light in a small area.
Best used for: track lighting, overhead recessed lighting

Floods: Also known as reflectors, think of these as giant spots. They cast a wider directional light than spots.
Good for: outdoor lighting, recessed cans indoors, landscape lighting and motion sensing fixtures

Decorative: These bulbs are designed to provide ambient and accent lighting and are generally shaped like candles.
Good for: wall scones and decorative fixtures, chandeliers

A-line: This is your classic all-purpose incandescent light bulb, just shaped more like an A than the traditional sphere. You use these in lamps and for general room lighting as they disperse light at a wide angle.
Good for: room lamps, reading lamps, hallways

Globe: These are almost completely round and can emit light in every direction.
Good for: bathroom vanities, living room lamps, pendant lights

The above is a summary of the general shapes and uses you will come across. The chart below goes into more depth on where different shapes work best. (Note: the spiral shape is really only found in CFL bulbs)


Choose Your Brightness
At this point, throw away everything you used to know about light bulbs. LEDs are not measured by wattage, because they use so little electricity. Instead, you need to focus on the lumen output—the amount of light the light emitting diodes inside your bulb will produce. For optimal energy efficiency, you want high lumens (amount of light) and low wattage (amount of energy). So as not to confuse consumers too much, most LED bulbs indicate on the package what their equivalent wattage is (a 5-watt LED equals the same light as a 40-watt incandescent). However, sooner rather than later, you’ll need to know all about the lumens. Use this chart to help you get there:


Choose Your Temperature
Early complaints about energy-efficient LEDs were directed at the type of light they gave off—the cold blue glow was discouraging and not ideal in a home setting. Today’s LEDs come in any color under the rainbow (literally), but you can also choose what color “white” you want.

The “color” of light is measured in Kelvins (K)—the lower the number the warmer the light. As a base to work from, if you were looking for a warm light, similar to that of an incandescent, look for between 2,700K and 3,500K, (for reference 5,000 would be as bright as direct sun light). Most LED bulbs indicate their color temperature using familiar words, such as soft white and bright white, but you can also reference the K rating of the light on the packaging:

  • Warm / Soft White (2,700K to 3,500K)—yellow tinted, ideal for indoor use and the closest to traditional incandescent light
  • Bright White (3,500K to 4,100K)—slight blue tint, brighter, ideal for high-traffic areas and workspaces where you need good illumination—hallways, laundry rooms and kitchens
  • Daylight (5,500K to 6,500k)—super bright, mimics daylight, ideal for reading, task lighting and outdoor use


Another number you may see on bulb packaging is the light’s CRI. This stands for Color Rendering Index, which measures the quality of the light the bulb gives off. It is not an indication of color itself, just the accuracy of the color. The range is 0 to 100, with 100 being the highest quality. Most LEDs clock in at about 80, which is perfectly fine for home use. So you really don’t need to worry about factoring this number into your decision making process, unless accurate light quality is crucial to a task you are performing (in which case look for a bulb with 90 CRI or higher, such as the Cree TW Series LED).

Consider Lifespan
Most LED bulbs promise a lifespan of on average 20 years. This is based on a projected number of hours the bulb will last (usually between 20,000 and 35,000 hours—the larger bulbs generally boasting the longer lifespan), when operated for a certain number of hours a day (normally three). As LED bulbs haven’t been in the market for 20 years, it’s hard to prove or disprove these claims. However as the cost savings touted around LEDs are factored based on this extraordinary longevity, it’s worth looking for a bulb that comes with a long manufacturer’s warranty. For example, Cree warranties their bulbs for 10 years and Philips offer 6 years of protection.

Other Fun Features
By this point, you are hopefully narrowing in on your potential bulb-of-choice. But then you see two identical-looking bulbs—only one is $10 more than the other. Welcome to “features.”

LED bulbs come with a wide variety of additional features to choose from, and while you could just grab the cheapest bulb and go at this point, you might want to consider picking up an option with one or more of the following features. After all, you’re going to have this bulb for somewhere between 20 and 30 years.

LEDS don’t always work with pre-existing dimming switches, so if your set up includes dimming you’ll want to make sure your bulb is compatible with traditional incandescent dimmers. Alternatively, you can upgrade your dimmer switch.

Bulb Pick: The $15 Philips 11-watt A19 LED Household Dimmable Light Bulb (830 lumens, 2,700K and a 25,000 hour lifespan) is a great all-rounder in this space. You can use it anywhere you would put a traditional 60-watt incandescent.

Wi-Fi Enabled
The trend for “connected” light bulbs is not going away anytime soon. Considering that you can now get a 60-watt equivalent LED bulb for the same price as a traditional one (although you’ll need to purchase a hub to control them), it is a great option for those interested in having a “smart home.”

Connected bulbs turn on and off just like regular ones, but can also be controlled by a smart phone or tablet app from within the home, or from anywhere with an Internet connection. For a roundup of some of the best options in the smart bulb space, read this article (LINK:

Bulb Pick: GE Link ($15 A-Line; flood also available). This dimmable, connected bulb replaces your 60-watt bulbs while outputting 800 lumens of soft white, 2,700k indoor light and promising close to 20,000 hours of life.

Color Changing
While you can pick up a connected bulb for $15, you can also spend $60 on one. It’s at this point that the trend toward improving light bulbs with technology actually becomes life changing. Philips’ Hue light bulbs are simply extraordinary. With the ability to match any color in the spectrum with just a swipe of your finger, your room can resemble a ski lodge in Austria, a mid-summer’s meadow, or an ‘80s discothèque. The possibilities are endless. The bulbs are capable of displaying 360 to 600 lumens, have a lifespan of 15,000 hours, and a range of 16 million color combinations. Hues are currently available as A-Line (A19) or Floods (BR30), and they also have a variety of accent lighting options.

Bulb Pick: Philips Hue ($60)

Flat Bulbs
Another recent innovation in the LED bulb space is the Philips SlimStyle bulb. A flat light bulb, these are very lightweight and, due to the unique design which addresses an issue of heat sink in most LED bulbs, use less materials to build them. This means they are lightweight and inexpensive, costing as little as $8.97. The SlimStyle comes in a 60-watt and 75-watt equivalent and works wherever a standard A-line bulb will. However, its unique shape means it will work in some places your traditional A-line will not.

Bulb Pick: Philips SlimStyle ($8.97), 800 lumens, gives off 2,700K for 25,000 hours.

3-Way Light Bulb
3-Way LED bulbs are also new in the LED space. Currently there are only three brands that manufacture them, but that’s three more than a year ago—an illustration of how quickly the space is developing. Used in lamps with built-in dimming capability, a 3-way bulb combines three different light levels in one bulb, giving you the effects of dimmable light without the dimmer.

Bulb Pick: Philips 3-Way LED ($20) at 470/840/1620 lumens (equivalent to 40/60/100 watt incandescent), gives off 2,700K light for 25,000 hours

Now that your education is complete, feel free to proceed to the nearest hardware store armed with all the information you could need.

Jennifer Tuohy is not only a technology geek but also a green mom who shares her knowledge for The Home Depot about how technology can save energy and money. You can find a wide selection of the LED lights bulbs, including the Hue lights, at The Home Depot.

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