Types of Light Bulbs: A Complete Guide

Candace Nelson
Written by Candace Nelson
Updated September 15, 2022
Group of friends enjoying a dinner at home
Photo: 10'000 Hours / DigitalVision / Getty Images

Highlights

  • LED bulbs are efficient and last 20 years, making them a lighting aisle favorite.

  • Lighting facts on light bulb boxes help you choose the right option for your room or fixture. 

  • Light bulbs come in various shapes and sizes to fit the vibe you’re creating.

  • Choose warm color temperatures for living rooms and bedrooms and cool temperatures for kitchens and offices.

  • Make sure to get the right base for your light fixture since light bulbs don’t all twist in.

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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.

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.

CFL Light Bulbs

With their signature twisty-tube design, compact fluorescent—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. It can also help reduce how often you change your light bulbs.

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

Close-up of two retro incandescent light bulbs
Photo: Chonticha Vatpongpee / EyeEm / Getty Images

This light 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.

Incandescent bulbs last an average of one year 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. 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, so they’re becoming less common. These bulbs are about 25% more efficient than incandescent ones, though.

HID light bulbs are common in commercial, industrial, or outdoor settings. They use mercury or sodium vapor to generate light.

Other Fluorescent Lights

You might know the old flickery fluorescent tubes in schools, offices, and the occasional basement. They’re distinctive because they tend to come in 3-foot-long tubes. They can last a decade, but fluorescent lights can also turn faulty before they’re completely out. 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 the 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 1600 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, expected lifespan, and where the bulb falls on the warm-cool spectrum.

What Are Watts?

Watts measure electricity. Check the light fixture for the maximum watt 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. 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

Candle light 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. They usually won’t see them in workspaces or for reading light.

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 light therapy lamps.

Bulb Types by Size 

A woman changing a light bulb at her home
Photo: Johner Images / Getty Images

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 and mount. 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. 

Visual comparison of 5 light bulb types, including LED, CFL, fluorescent, incandescent, and halogen
Images (left to right): grapestock / Adobe Stock, Kybele / Adobe Stock, The Toidi / Adobe Stock, supachai / Adobe Stock, Piotr / Adobe Stock

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 are 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 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.

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