Understanding Different Types of Light Bulbs: A Complete Guide (2024)

Walking down the lighting aisle, you might be overwhelmed by the types of light bulbs: LED, CFL, halogen, and incandescent bulbs. You just want a bulb that will last a long time and won’t waste too much energy while it lights your path. Luckily, this can be very easy to find, provided you have a few pieces of knowledge. Here’s a look at some of the more common light bulb types you’ll come across in your search and what to choose for each room.

Types of Light Bulbs

Light bulbs come in many forms and use different amounts of energy. Here’s a guide to choosing wisely from the different main types of lighting.

LED Light Bulbs

Light-emitting diode (LED) bulbs are currently the darling of the lighting aisle. Lasting up to 20 years, LED bulbs have overtaken CFL bulbs as the most efficient, energy-saving bulbs. They cost more than CFL bulbs, but the long life makes them worth the added price. There are also several types of LED light bulbs, meaning there’s always a good option for your specific needs.

CFL Light Bulbs

With their signature twisty-tube design, compact fluorescent lamps (commonly called CFL bulbs) light the way.

They cost more than incandescent bulbs, but their energy efficiency makes them worthwhile long-term. Because they create light by exciting gasses rather than heating up a wire, CFL bulbs are less prone to breaking or going out. This gives them a nine-year lifespan, so the upfront cost pays for itself over time. The various types of fluorescent bulbs also give you options for size, color, and brightness.

CFLs contain mercury, so instead of throwing them out, you'll need to recycle them. Your local retailer is likely to accept them for recycling, so be sure to take advantage of that.

Incandescent Light Bulbs

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What is an incandescent bulb? This is the original bulb design, and it’s probably what pops into your mind when you imagine a light bulb. This bulb type is mostly absent from homes and store shelves these days. Incandescent lights burn hot and are poor energy savers compared to CFLs, although some people are partial to their warm glow.

Comparing incandescent bulbs vs. LED or other bulb types, there’s simply no competition. Incandescent bulbs last an average of one year (compared to hundreds or thousands of hours for LEDs and CFLs) and can waste energy. Your home and your electricity bill are likely better off with other choices.

Halogen and HID Bulbs

You’ll also see halogen and HID (high-intensity discharge) bulbs in the lighting aisle. HID light bulbs are common in commercial, industrial, or outdoor settings. They use mercury or sodium vapor to generate light. They cast a stark white light and are often used for task-specific lighting like directed spotlights or in the kitchen. Other common uses are outdoor lighting and in-track lighting systems.

Varieties of halogen bulbs aren’t as efficient as CFL and LED lighting and only last about a year like incandescent bulbs, so they’re becoming less common. These bulbs are about 25% more efficient than incandescent ones, though.

Other Fluorescent Lights

You might know the old flickery fluorescent tubes in schools, offices, and the occasional basem*nt. They’re distinctive because they tend to come in three-foot-long tubes. They can last a decade, but fluorescent lights can also turn faulty before they’re completely out, meaning they’re only a slight improvement when comparing bulb types, such as fluorescent vs. incandescent bulbs. These are uncommon in updated homes, so chances are, these aren’t the ones you’re seeking.

As with CFLs, you must recycle fluorescent lights properly.

Lumens vs. Watts: Understanding These Lighting Variables

You’ll see lumens and watts listed on the box when you purchase bulbs. Here’s what these terms mean:

What Are Lumens?

Lumens measure the amount of light emitted from the bulb. The higher the number, the brighter the light. A 100-watt incandescent light bulb is equal to 1,600 lumens.

Light bulb packages now have a lighting facts label—similar to the nutrition facts label you’re used to seeing on your groceries. It gives you the cost per year, the expected lifespan, and where the bulb falls on the warm-cool spectrum (more on that in a moment).

What Are Watts?

Watts measure electricity. Check the light fixture for the maximum wattage of light bulb it can support. Never go above this number because some light bulbs burn hot, so this can be a fire hazard. It’s always fine to use a lower-wattage bulb than the fixture can support—you’ll just get less light.

Types of Light Bulbs by Color Temperature

Different light bulbs give off different color temperatures. Some bulbs give off a warmer yellow glow, while others give off a cooler blue light. Deciding the winner between warm vs. cool light is all about personal preference, so keep it in mind when choosing bulbs. You’ll see color temperature on a box of bulbs, and it’s described using the Kelvin scale (abbreviated as K). Warmer color temperatures are lower on the scale, and cooler temperatures are higher on the scale.

Candlelight

Candlelight bulbs give off a warm, vintage light reminiscent of the flame of a candle and have a Kelvin score of about 1,000K to 2,600K. You have probably seen them in decorative chandeliers or sconces. You usually won’t see them in workspaces or for reading light, as they’re more intended for ambient light and don’t cast a lot of illumination.

Warm White

Kelvin temperatures around 3,000K give off warm white light like an incandescent light bulb or a candle. This soft ambient light works well in bedrooms and living rooms. Warm white light is relaxing to the eye and feels inviting.

Neutral White

Neutral white light has a Kelvin score of around 4,000K. It has a modern feel that isn’t too yellow or too blue. Use it in spaces where color perception matters. It makes a great choice for a bathroom vanity mirror or for photographing items for resale.

Cool Blue

Lights above 5,000K cast a cool blue light. They are perfect for task lighting in a home office or kitchen. They can also be a smart choice for outdoor flood lights and different types of security lighting.

Daylight

Light bulbs marked daylight have a Kelvin score of around 6,500K. As the name implies, these bulbs mimic the light you see outdoors in the middle of the day. This light is most likely too harsh for use in the home. The blue light can make it especially tough to relax in the evening.

Daylight bulb use is usually best for workspaces for artists and photographers and for light therapy lamps.

Bulb Types by Size

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When you see a reference to a Type A, Type S, or Type B light bulb, that indicates the general shape and size of the bulb as well as the type of light bulb base. Different fixtures will call for different types of light bulbs.

Type A Light Bulb

This is the type you’re probably most familiar with, going all the way back to Edison. Type A is a roundish bulb with a relatively wide mount on the bottom. Most light bulbs, regardless of CFL, LED, or incandescent status, use this mount.

Type B Light Bulb

This is a much slimmer version of the Type A mount. The bulb itself is generally narrow and bullet-shaped or flame-shaped. This style of bulb is most popular for decorative purposes, such as in candelabra-style lighting fixtures.

Type C7/F Light Bulb

A C7 light bulb is a candle-shaped bulb often used in night lights and holiday lights. Sometimes they’re smooth, and sometimes the bulb has a decorative texture. The base of a C7 bulb is a candelabra size.

Type S Light Bulb

Type S doesn’t refer to the mount; rather, it indicates the shape. Type S light bulbs are shorter, rounder-shaped bulbs that can use the same mount as a Type A or Type B light bulb.

Type G Light Bulb

Type G lights are big and round. They are often used in a row on a vanity to give off bright light. However, use isn’t limited; Type G light-bulb bases fit in any standard fixture.

Type PS Light Bulb

PS stands for pear straight. These bulbs are pear-shaped with a rounded, oblong end similar to Type A. They work indoors or outdoors in light fixtures designed for a bulb with a longer neck than Type A.

Different numbers after PS indicate the diameter of the light bulb. One inch is 8, so PS-16 is 2 inches. Other common sizes include PS-25, which is 3.125 inches in diameter and PS-35 is 4.375.

Type R Light Bulb

Type R light bulbs have a floodlight style with a flat end. R lights have a reflective coating that distributes light evenly as it’s reflected back. The light appears brighter, making it a good choice for task lighting.

Type MR Light Bulb

Often a halogen style, the MR bulb plugs into the socket with two prongs. You’ll often see MR light bulbs in kitchens.

Types of Light-Bulb Shapes

Light bulbs come in a variety of shapes for different uses or to match a light fixture’s style. For example, a globe light bulb may inspire bathroom vanity lighting ideas while a floodlight is best for the security lights around the outside of your home.

Standard

Also referred to as A bulbs, standard light bulbs make up the majority of light bulbs used in homes. They’re shaped like a hot-air balloon with necks of varying lengths. Get them in a variety of color temperatures for most of your lighting needs.

Globe

Globe-shaped bulbs are rounded with a short neck. These give off bright light, and you can use them for precise work like applying makeup in your bathroom. The shape is also appealing for decorative purposes.

Capsule

Capsule light bulbs pack the bulb in a small space. With two prongs, they fit in specialty fixtures, like ceiling fans or under-cabinet lights. They come in warm or cool temperatures and different lengths.

Candle

Candle-shaped bulbs are widest toward the base and then get narrower. These are small bulbs used for decoration or as soft light in night lights. Find them in different temperatures and with colored glass.

Candle Angular

Candle angular bulbs start out candle-shaped but add some flair with a decorative wisp at the end. These light bulbs give off a vintage vibe and are popular for decoration. Look for clear or amber hues.

Tube

Also called tubular, tube light bulbs are shaped like the tubes in high school science classes. They’re long and thin, and their design makes them highly efficient and excellent choices for providing bright task lighting.

Spiral

The spiral shape is usually indicative of a CFL bulb, which is rare nowadays. You can also find decorative light bulbs with a twisted shape.

Floodlight

Floodlights have a big, flat end to evenly flood an area with uniform light. You’ll usually see them outdoors for lighting the driveway basketball court for evening games or as bright motion lights.

Specialty

The specialty category of light bulbs can be diverse. It includes heat bulbs, projector bulbs, black lights, and novelty shapes and colors—orange skeleton light, anyone?

Common Light-Bulb Base Types

It’s important to know which bulb base will fit into your fixture since some are different shapes and not all twist in. Knowing the base will help you choose the best light bulb for your space.

Medium

A medium base is the standard twist-in light bulb for most household lighting sources. You’ll easily find these lights at hardware stores.

Candelabra

A candelabra is also a twist-in light bulb, but it’s smaller than a medium base.

Intermediate

An intermediate light-bulb base is a twist-in that’s bigger than a candelabra but smaller than a medium.

Pin-Type

Pin light-bulb bases usually have two prongs that push into the light fixture.

Push and Lock

Push and lock light-bulb bases are similar to the pin type in that they have two prongs. The prongs push into the fixture, and then the fissure is turned slightly to lock it in place.

Which Type of Light Bulb Is Right for You?

As you can see, there are actually many aspects to consider about the humble light bulb. Choosing from the many varieties is a matter of thinking about the fixture you’re using, the lifespan of the bulb, the color and temperature of the light, and the purpose of the light in a given space.

If you’ve read through this guide and still aren’t sure which light bulb is the best choice for your specific situation, a local lighting installation expert could be the help you need—they can use their extensive experience to help you choose the best bulb for any scenario.

Candice Nelson contributed to this piece.