In This Article
- The 4 Types of Lightbulbs
- Understanding Lightbulb Brightness (Lumens)
- Understanding Lightbulb Power (Watts)
- Understanding Lightbulb Color Temperature (Kelvins)
- The Different Lightbulb Shapes
- Understanding Lightbulb Bases
- How to Choose the Right Lightbulb for Your Space
Lighting can dramatically impact the way your space looks and feels, so it’s the kind of thing you want to get right. The only problem? There are tons of lightbulbs on the market, and navigating all those options can be tough—especially when you’re bombarded with jargon like lumens, Kelvins, and watts.
The good news? There isn’t that much information to master, and after a quick lesson on lightbulb types, brightness, and color temperature, you should be well on your way to choosing lightbulbs for your space like a pro.
The 4 Types of Lightbulbs
Browse the lightbulb section at your local hardware store, and you’ll find all kinds of different lightbulbs. Thankfully, there are really just four types of lightbulbs you need to know about: CFL lightbulbs, halogen lightbulbs, incandescent lightbulbs, and LED lightbulbs.
CFL Lightbulbs
Looking for a lightbulb that’s energy-efficient, long-lasting, and budget-friendly? Consider a CFL (compact fluorescent lamp) lightbulb. With an average lifespan of 7–9 years1, CFL lightbulbs are longer-lasting than halogen and incandescent lightbulbs. And they tend to be budget-friendlier than LEDs, despite being similarly energy-efficient. Available in a range of color temperatures, CFL lightbulbs should make an easy addition to most homes. Just remember that they contain mercury2—so they’re not the kind of thing you want to drop.
Halogen Lightbulbs
Bright but dimmable, halogen lightbulbs are a popular choice for recessed lighting, under-cabinet lighting, and more.2 The lightbulbs are more energy-efficient than incandescent lightbulbs, but less energy-efficient than CFLs and LEDs. And though they’re incredibly budget-friendly, they don’t boast a very long lifespan. (You should expect your halogen lightbulbs to last about 1–2 years.1) Since halogen lights get hot, you’ll want to exercise caution when handling them. You’ll also want to avoid touching them with bare hands. (The oils in your hands may cause the lightbulbs to explode.)2
Incandescent Lightbulbs
Incandescent lightbulbs are some of the most popular around. Warm but dimmable, incandescent lightbulbs are a great pick for most homes. And since they’re the most budget-friendly lightbulb type in this bunch, they’re incredibly easy to stock up on. That said, incandescent lightbulbs are not very energy-efficient. And with an average lifespan of 1–2 years1, they’ll need to be replaced pretty regularly.
LED Lightbulbs
It’s not hard to see why LED (light-emitting diode) lightbulbs have become so popular. Though the lightbulbs are bright, they’re incredibly energy-efficient. And they’ll last a really long time. Boasting an average lifespan of 9–22 years1, LED lightbulbs are not the kind of thing you’ll have to replace frequently. And since they don’t contain mercury—and shouldn’t break when touched—they’re more low-maintenance than some of the other bulbs on the market. (We’re looking at you CFL and halogen, lightbulbs.) Unfortunately, this convenience comes at a cost: LED lightbulbs are some of the most expensive you’ll find.
As you can see, every type of lightbulb has its own pros and cons. Some win on price, some win on longevity, and some win on energy efficiency. So when choosing lightbulbs for your space, try to balance all of these factors. Would you rather have an expensive, energy-efficient lightbulb that you can leave alone for up to two decades, or would you rather stock up on budget-friendlier lightbulbs you’ll have to change out more frequently?
Understanding Lightbulb Brightness (Lumens)
A big part of lighting your space is getting the brightness right. Make a room too dim, and it’ll be tough to see. Make a room too bright, and you might be in for a headache. So when choosing lightbulbs, you’ll want to pay attention to brightness, which is measured in lumens. More lumens means more brightness—the higher the lumens, the brighter the bulb.
Of course, more brightness isn’t always better. Task-based spaces, like home offices and kitchens, typically need a lot of light. But cozier spaces like dining rooms could benefit from a dimmer atmosphere. When figuring out how bright your lightbulbs should be, you’ll want to consider two things: the size of the room you’re lighting, and the kind of room you’re lighting.
Start by getting the square footage of the room.3 (Measure the room’s length and the room’s width, then multiply the two.) Then, you’ll want to multiply your square footage by another number—depending on the kind of room you’re lighting.3
Garage: x 80–100
Kitchen: x 70–80 (for work areas), x 30–40 (for general lighting)
Bathroom: x 70–80
Home Office: x 60–80
Dining Room: x 30–40
Living Room: x 10–20
Bedroom: x 10–20
Hallway: x 5–103
These coefficients represent the number of foot candles you want in each room. Foot candles measure how bright a light source looks when you’re standing 1 foot away.3 So the higher the number of foot candles, the brighter the light source.
Multiply the room’s square footage by the appropriate number of foot candles, and you’ll end up with a pretty big number. This is the number of lumens you need in the room—or, put differently, how bright the room needs to be. (For simplicity’s sake, we’ll call it the room’s brightness number.)
Remember that you can add lumens in two ways: installing more lightbulbs or installing brighter lightbulbs. So consider how many lightbulbs you can install in your space. Then, make sure the lightbulbs you’re installing are bright enough (or dim enough) to help you meet your room’s brightness number.
Understanding Lightbulb Power (Watts)
Watts will tell you how powerful a lightbulb is. And by powerful, we mean: how much power the lightbulb will use.
Back in the day, watts were a good indicator of how bright a lightbulb would be. (A high-watt bulb was brighter than a low-watt bulb.) But now that energy-efficient options abound, lumens are a better indication of brightness. (A low-watt LED may be brighter than a high-watt incandescent lightbulb.)
So when looking at watts, all you’re really thinking about is how energy-efficient—or energy-inefficient—the lightbulb is.
CFL Lightbulbs: use between 3–120 watts
Halogen Lightbulbs: use between 5–500 watts
Incandescent Lightbulbs: use between 5–500 watts
LED Lightbulbs: use between 2.5–16 watts（1）
Understanding Lightbulb Color Temperature (Kelvins)
In addition to being bright or dim, light can be warm or cool. And when you’re talking about how warm or cool the light is, you’re really talking about the light’s color temperature. Color temperature is measured. on the Kelvin scale.（4） A lower Kelvin number means a warmer color, so you can expect the light to have more yellow undertones. A higher Kelvin number means a cooler color—so light with bluer undertones.
Soft White (lots of yellow undertones): 2,700–3,000 Kelvins
Warm White (some yellow undertones): 3,000–4,000 Kelvins
Bright White (some blue undertones): 4,000–5,000 Kelvins
Daylight (lots of blue undertones): 5,000–6,500 Kelvins（4）
When choosing a color temperature for your space, you’ll want to consider two factors: your personal preferences and the kind of room you’re lighting. Many of us have strong preferences about the kind of light we like. We know we like warm light, cool light, or somewhere-in-between light. And since you’re choosing lightbulbs for your home, it’s worth keeping these preferences in mind.
Then, consider the room you’re lighting. Warm light tends to feel softer and more welcoming, making it a great pick for cozy spaces, like the living room or dining room. Cool light tends to feel brighter and crisper—the kind of thing you want in a task-oriented environment, like a home office.
That may sound like a lot to figure out. Thankfully, industry experts have an easy rule of thumb to follow:
Living Room: 2,700–3,000 Kelvins
Dining Room: 2,700–3,000 Kelvins
Bedroom: 2,700–3,000 Kelvins
Kitchen: 2,700–4,000 Kelvins
Bathroom: 3,000–4,000 Kelvins
Home Office: 3,000–5,000 Kelvins
Garage: 3,000–5,000 Kelvins（5）
As you can see, the color temperature should be lower in cozy spaces (meaning the light should be warmer) and it should be higher in task-oriented spaces (meaning the light shoulder be cooler).
Now that you know how to choose the right color temperature for your space, you’ll need to find lightbulbs that can get the job done. Some lightbulbs—like incandescent lightbulbs and halogen lightbulbs—only put off warm light. Others—like CFL lightbulbs and LED lightbulbs—are available in many different color temperatures.
CFL Lightbulbs: 2,700–6,500 Kelvins（6）
Halogen Lightbulbs: 3,000–3,500 Kelvins
Incandescent Lightbulbs: 2,700 Kelvins（7）
LED Lightbulbs: 2,700–6,500 Kelvins（8）
The Different Lightbulb Shapes
Once you know what kind of lightbulb you want, you can think about what your lightbulb looks like. Lightbulbs come in an array of different shapes.（9） And each shape has a name—and a corresponding alphanumeric code—you can use to find the exact lightbulbs you’re looking for.
The letter in the alphanumeric code will tell you what type of lightbulb you’re looking at. The number in the alphanumeric code represents the diameter of the bulb at its widest point, measured in eighths of an inch.（10） (So an A15 lightbulb is an A series lightbulb with a diameter of about 15/8”, or 1.875 inches.)
A Series Lightbulbs: Boasting a round top and a tapered base,11 A (arbitrary) lightbulbs12 are probably what you picture when you hear the word “lightbulb.”
B Series Lightbulbs: Great for chandeliers and sconces, B (blunt-tip) lightbulbs12 are tapered at the base, wider in the middle, and tapered at the top.11
BR Series Lightbulbs: BR (bulged reflector) lightbulbs12 are narrow at the base and wide at the top.11
BT Series Lightbulbs: BT (blown tube) lightbulbs12 are narrow with a blown-glass bubble in the middle.10
C Series Lightbulbs: C (conical) lightbulbs12 are round at the base, wider in the middle, and tapered at the top.11 (If you’ve ever seen string lights with pointed bulbs, these are probably what you were looking at.)
CA Series Lightbulbs: CA (conical angular) lightbulbs12 look a lot like C lightbulbs. They’re round at the base, wider in the middle, and tapered at the top—but their tapered tip is bent over.11
G Series Lightbulbs: G (globe) lightbulbs12 are completely round.11 (If you’ve seen string lights with ball-shaped bulbs, those were G lightbulbs.)
MR Series Lightbulbs: MR (multifaceted reflector) lightbulbs12 look like half-spheres.11 They’re narrow at the base, round at the middle, and flat at the top.
PAR Series Lightbulbs: PAR (parabolic aluminized reflector) lightbulbs12 are popular in commercial settings. They’re shaped like MR lightbulbs, with a narrow base, a wider head, and a flat top.11
PL Series Lightbulbs: PL (plug-in fluorescent lamp) lightbulbs13 are fluorescent lights that you can plug directly into an outlet.
R Series Lightbulbs: R (reflector) lightbulbs are narrow at the base, wider at the head, and flat along the top11
LED Light Bulbs. Warehouse-Lighting.com.
Thanks to this silhouette, R lightbulbs put off a lot of light—making them a popular choice for lighting large rooms or hallways.11
T Series Lightbulbs: T (tubular) lightbulbs are exactly what they sound like: lightbulbs that look like tubes. Some plug directly into outlets, while others slide inside fixtures like normal bulbs.
This isn’t an exhaustive list of lightbulb shapes. (Yes, there are even more than this.) But the truth is, most of the time, you’ll be just fine with an A-series lightbulb.
If you want your lightbulb to double as a decorative accent—or to serve some specific purpose (like lining a candelabra or lighting a work of art)—you may want to experiment with some of these other shapes. But if all you need is a basic lightbulb that can effectively light your space (and that can fit most fixtures), a standard lightbulb should do.
Understanding Lightbulb Bases
Once you’ve found a lightbulb that ticks all your boxes, there’s one final thing to consider: What does the lightbulb’s base look like? When shopping, there are three types of lightbulb bases you should be aware of: screw bases, pin bases, and twist and lock bases.2 And the biggest difference between the types is how they attach to a light fixture.
Screw Bases
If you’ve ever seen a lightbulb with a spiralized base, you’ve seen a screw base. These bases are designed to screw inside fixtures. And when shopping, you’ll see them designated by E series alphanumeric codes. (Some of the alphanumeric codes from the Lightbulb Shapes section tell you what shape the base is—not what shape the bulb is.)
Pin Bases
Some fluorescent lightbulbs have pin bases. This means that instead of screwing into a light fixture, the bulb clips into the light fixture using pins. When shopping, you may see these pin bases designated by G series alphanumeric codes.
Twist and Lock Bases
Some lightbulbs twist and lock into fixtures using pins. These lightbulbs will also be designated by G Series alphanumeric codes.
Most of the time, you’ll see screw bases. But on the off-chance that you’re dealing with a pin base or a twist and lock base, just make sure the lightbulb is appropriate for the fixture you’re trying to put it in.
How to Choose the Right Lightbulb for Your Space
Step 1: Think About the Room You’re Lighting
Ask a few questions about the room you’re trying to light. How big is the room? What function does the room serve? And how do you want the room to feel once it’s finished?
Step 2: Calculate How Bright the Room Should Be
Once you know how big the room is—and once you understand what purpose the room needs to serve—you can figure out how bright the room needs to be. Multiply the room’s square footage by one of the coefficients listed in our Lightbulb Brightness (Lumens) section. This will tell you how many lumens you need in the room.
Divide this total brightness number by the number of light fixtures you plan to put in the room. This will tell you, on average, how bright each bulb in the space should be.
Step 3: Decide What Color Temperature the Room Should Be
Now that you’ve gotten the room’s brightness under control, consider whether you want the room to feel warm, cool, or somewhere in between. Use the rule of thumb listed in our Lightbulb Color Temperature (Kelvins) section as a starting point—it will tell you how warm or cool a room should be, given its purpose.
Then, use that target color temperature to narrow down your lightbulb choices. Typically, you’ll have four types of lightbulbs to choose from: CFL lightbulbs, halogen lightbulbs, incandescent lightbulbs, and LED lightbulbs. If you’re going for a warm color temperature, you’ll still have your choice of all four. (All four can put off warm light.) But if you’re going for something cooler, your options will be limited to just CFL lightbulbs and LED lightbulbs.
Step 4: Consider Price, Longevity, and Energy Efficiency
Once you’ve locked down a color temperature, you’ll either have four types of lightbulbs to choose from—or two types of lightbulbs to choose from.
If you have four options to choose from, take a moment to consider factors like price, longevity, and energy efficiency.
CFL lightbulbs are generally budget-friendly, somewhat long-lasting, and very energy-efficient.
Incandescent lightbulbs are very budget-friendly, not long-lasting, and not energy-efficient.
Halogen lightbulbs are very budget-friendly, not long-lasting, and somewhat energy-efficient.
LED lightbulbs are not very budget-friendly, very long-lasting, and very energy-efficient.
Remember that some lightbulbs have other unique tradeoffs: CFL lightbulbs contain mercury, and halogen lightbulbs should only be handled with gloves.
If you have two options to choose from, you’re really just weighing price and longevity. CFL lightbulbs are budget-friendlier than LED lightbulbs, but last about half as long. LED lightbulbs are more expensive, but they’ll last a lot longer. And since they don’t contain mercury, you won’t have to be quite as careful when handling them.
Step 5: Consider the Lightbulb’s Shape
This step is optional. If you’re looking for a standard lightbulb, you can simply buy a standard lightbulb. But if you’re looking for a lightbulb that looks striking or that serves a specific purpose, you may want to consider lightbulbs of different shapes.
Step 6: Make Sure the Lightbulb Has a Suitable Base
Now that you’ve reached the end of your lighting journey, make sure the lightbulb you’re eyeing has an appropriate base. As long as the lightbulb’s base matches up with the fixture you’re trying to put the lightbulb in, you should be good to go.
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