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Buying Guide

Purchasing an LED lightbulb can be confusing. The bulb descriptions are no help, being a jumble of numbers and letters that aren’t self-explanatory. This page is going to be your cheat sheet. The bottom line is that some numbers and letter in bulb product descriptions matter and some don’t. The outline below contains the most useful lighting terms, along with their accompanying letters and numbers that you can use as search terms and to decipher product descriptions and the numbers that go along with them: lumens, the Kelvin scale, and the Color rendering Index (CRI). This page also provides links to products from recognizable retailers, however isn’t an endorsement.

Lumens & Watts

Most large retailers have realized that Lumens confuse consumers and therefore list many bulbs with the wattage that they are intended to replace. However, Lumens are a better measure of what a lightbulb does: provide brightness. Watts measure the bulb’s energy use. Understanding the distinction can help you purchase bulbs confidently.

Familiarizing yourself with the table below is enormously useful. They are the primary numbers that retailers use to describe bulbs.

Familiar WattageLumens EquivalentNew Wattage 

Kelvin scale (K)

Another common number you’ll see is Kelvins measure, ranging from 2000 – 6500. If you confuse this number with Lumens, you might be unhappy with your purchase. The good news is that the Kelvins measurement always has a K following it – 2700K, 5000K, 2200K. Most consumer bulbs come in a standard 2700K – 3000K. The bottom line: don’t confuse Kelvins with Lumens.

K scaleTemperature effectLocations/Applications
2000-2200Warmest, amber light. Can be perceived as too dim. Not good for reading.Homes, libraries (not the reading lamps), restaurants
2700 – 3000KWarm, relaxing, everyday light. Most common in households – in living rooms and bedrooms.Homes, hotel rooms, lobbies, restaurants, retail stores
3500Neutral. Crisp, fresh and bright.Public reception areas, executive offices, supermarkets
4000Cool, very bright white. Can be perceived as harsh.Classrooms, offices, showrooms
5000 – 6500Bright daylight. Energizing, alert.Jewelry stores, hair salons, galleries, museums.

Other important measurements.

CRI (color range index). This number falls on a scale from 0 (poor) to 100 percent (perfect) and describes how thoroughly a light source, like a lamp, reveals the “colors within a color” – also known as nuance or dimension. In other words, there are more colors present than “blue” in something blue, but we can’t see it until the lighting conditions are good enough to reveal it. The CRI is the measurement of those conditions, 100 being “will absolutely reveal all the colors within this color” to 0 “won’t reveal any of the colors within this color.” A sunny day has a good CRI, a cloudy day less so, but a cloudy day has a higher CRI than a dimly lit bar. A black shirt might look deeply black in that dimly lit bar but look dull outside on a sunny day. A black lab’s fur might look like the darkest brown or auburn at its ends when he’s outside in the bright sun, or a person’s eyes might seem to change color depending how cloudy the sky is. However, you would continue calling both the shirt and dog black and the person’s eye color blue but be aware of its nuance, complexity, and dimension.

Light bulb (lamp) bases: A19, E26: refers to base of lamp. A19s are what we think of as standard. E26s are skinnier, like a candelabra or night light bulb.

Product Guide

There’s a lot of info on bulb product descriptions but you can ignore a lot of it. Consider these examples: From Amazon: LED 9W/60W Replacement A19 Warm White (2700K) Dimmable Light Bulb, Energy Star Certified. What it means: LED 9W: the new Wattage. /60W Replacement: the Wattage it replaces. A19: Disregard – a standard measurement of its base. Warm White (2700K): disregard – standard measure of household lighting. Dimmable Light Bulb: self-explanatory. Energy Star Certified: the bulb meets federal requirements for energy efficiency. Applicable if you want a rebate through your utility. Most LED bulbs are Energy Star certified. Let’s look at the label again, crossing out all the standard info and leaving what’s important: LED 9W/60W Replacement A19 Warm White (2700K) Dimmable Light Bulb, Energy Star Certified. Here’s another one: Globe 6W LED.

Lamp bulbs

Energy-certified product lookup.

3-Way Lights for lamps

  • Ideal use: in bedrooms, living rooms, dining rooms, and hallways
  • Our trusted brand: Simply Conserve

Task and/or reading lamps

Any of the above bulbs are appropriate Fixtures: vanity, bathroom, dining rooms, kitchen, recessed lights 60-Watt Equivalent LED, dimming.

Goes from brighter, clearer light to amber light when dimmed.

Use: most household fixtures, such as pendant and vanity fixtures in bathrooms, dining rooms and kitchens, recessed lights. Use anywhere bulb is visible.

 75 Watt equivalent LED bulb:

100 Watt Equivalents LED bulb:

Recessed Lighting and Track Lighting

This is where lighting can get tricky because bulbs have changed constantly over the years and so have their descriptions. Below is a quick explainer with some important terms that are different from standard terms described above. Here’s a more detailed explanation from

You may see the following terms when you’re shopping for recessed or track lighting:

  • Recessed lights: hidden within the ceiling and are sometimes called can lights or canister lights.
  • Track lights: hang from the ceiling, with a visible fixture.

Important jargon for recessed lights: BR-20, BR-30, and BR-40. This measures the diameter of the top of bulb, rather than the base (A19, E26). You’ll need to measure the diameter of the bulb container because a BR40 bulb in a BR30-sized container will hang below the ceiling, creating an odd appearance.

Indoor recessed: 11 Watt LED bulb BR30, 65 watt LED equivalent

Candelabras and chandeliers

These lights are less standardized and vary depending on each fixture. Some elements to keep in mind when shopping.

  • They often use an E12 base, which is the thread, or bottom, of a lightbulb. Candelabras and chandeliers usually have thinner, longer threads than standard lightbulbs.
  • This bulb is the most dependent on the purchaser’s design sense.
  • The product’s length is important and will vary depending on the fixture. You often must search and click a link to detailed product measurements.

Lowe’s (Energy Star-certified products will show the blue logo in the upper-right corner of product’s thumbnail picture. The first four rows of search results are all Energy Star-certified.) 

Globe light, decorative, 4-6 Watt, 20-40 Watt replacement: Important terms: medium or large base. This refers to the height of the base, or the part that screws in to the socket. G30, G40, G50 refers to the bulb’s diameter. Globe lights are often used on their own, like in a bathroom vanity.

Tube LEDS (fluorescent replacements)

Fluorescent bulbs were the most energy efficient method for lighting before LEDs came along. Compared to incandescent lighting – the traditional bulb – fluorescents were cheaper, longer-lasting, and provided clear, bright light, especially popular in commercial spaces. In residences, the fluorescent bulb comes in either a tube shape or the CFL, which is shaped like a spiral staircase instead of the traditional globe. There is a lot of variety when shopping for fluorescent replacements. For the easiest experience, include in your search terms the desired shape of bulb, traditional or modern wattage that you need to replace, followed the length needed if replacing tube lights. Example: LED tube light 100 watt replacement 4 feet; or LED 60 watt bulb.


Vintage lightbulbs

Vintage lightbulbs are different from modern LED’s in their design. The product guidelines in the previous section apply for vintage LEDs. The one difference is the look. The link below will show you a page with a variety of shapes and sizes with the common E26 base. We want to leave design decisions to you.
One note before you begin looking. Vintage LED’s, because they are decorative – come in a variety of silhouettes, each with its own code. Remember the standard codes from the first section? A10 and E26? The “E” and the “A” refer to shape. The “26” is the base code, the part that holds the screw thread. The table below lists the most common shape codes. For a deep dive on shape codes, click here: For base codes:

Shape CodeDefinition
A (A19)Arbitrary (standard)
E, ED (E26, E12)Elliptical
SStraight sided
STSpherical Tubular
PSPear shape

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