Are you looking for a medium size pear-shaped bulb for general lighting? If yes, the A21 bulb is an ideal choice. Depending on your needs, this bulb size works great for both ambient and accent lighting. 

A21 bulbs are inverted pear-shaped bulbs with a diameter of 2.625 inches. These bulbs come with an E26 base, which is considered the standard base size in the US. You can use these fixtures for versatile lighting purposes like- commercial, residential, and industrial lighting. They come in different technologies, including- incandescent, halogen, CFL, and LED. However, LED A21 bulbs are the most energy-efficient variants. They operate in lower temperatures and last longer. Dimming, CCT adjustable, and other smart features are also available in these bulbs. 

Nevertheless, the length and diameter of the A21 bulbs vary for different wattage ratings. There are more such facts to explore about A21 bulbs. So, here I bought you everything you need to know about A21 bulbs: 

What Is An A21 Bulb? 

A21 bulb refers to a specific size of the traditional A-shape bulbs. The letter ‘A’ indicates the inverted pear shape of the bulb. The number ‘21’ indicates its diameter, eighths of an inch or 2.625 inches. However,  as 2.625 inches is equivalent to 66.675 mm, A21 bulbs are also known as A67 bulbs in countries that use a metric system. These fixtures are larger than A15 and A19 bulbs. These larger sizes make them ideal for both general and accent lighting. So you can use them for versatile purposes. 

Features Of A21 Bulb

The A21 bulb has unique features that separate it from other A-type bulbs. These are as follows- 

Dimension Or Size

ANSI C79.1 standards regulate the dimension or size of the A21 bulb. As discussed above, they have a diameter of 2.625 inches or 66.675 mm. However, the maximum length and diameter of the bulb vary for different wattage ratings. These are as follows- 

Bulb Base 

A21 bulbs always have an E26 base. These E26 bases are considered standard size in the USA, North America, Japan, and Vietnam. This base supports 110V-120V. So, A21 bulbs typically run at this voltage range. Besides A21 bulbs, A19 bulbs also have E26 bases. To learn more, check this- Are E26 And A19 The Same Thing?

Types Of A21 Bulbs

Based on technology, A21 bulbs can be of different types. As technology advances, energy efficiency increases, but the price of the bulb also becomes expensive. But in the long run, the energy-efficient ones become more cost-effective as they consume less energy, saving your electricity bills. Here, I am adding a detailed discussion of different types of A21 bulbs- 

1. Incandescent A21 Bulbs 

Incandescent A21 bulbs are the traditional fixtures that have tungsten filaments. They glow when electricity passes through these filaments. The major drawback of these fixtures is that they are not energy efficient. About 90% of the energy is converted to heat, and only 10% is transformed to light. Thus, these lights get extremely hot while operating. 

2. Halogen A21 Bulbs

Halogen bulbs are a better version of incandescent ones but have halogen gas inside. However, they also have filaments and are not environmentally friendly. But these fixtures are more durable and last longer than incandescent A21 bulbs. 

3. CFL A21 Bulbs

CFL stands for Compact Fluorescent Lamp. These fixtures have mercury vapor and phosphor coating inside. When electricity passes through these coatings and mercury, it produces UV light. CFL lights are an excellent replacement for incandescent bulbs and are more energy efficient. 

4. LED A21 Bulbs

LED A21 bulbs use light-emitting diodes to produce light. These fixtures use the latest lighting technology, which consumes less energy to produce illumination equivalent to traditional bulbs. This makes them highly energy efficient. You get many advanced features available in these fixtures compared to other variants. For example, they come with CCT adjustability, dimming features, and more. Besides, smart LED A21 bulbs also have motion sensor features. Some also integrate with mobile phones and apps. Thus, you can control the lighting of your space from anywhere at any time. 

Wattage Ranges

You will find A21 bulbs in different wattage ratings, making them suitable for versatile lighting. They are available in varying lighting technologies, from traditional incandescent A21 bulbs to the latest LED A21 bulbs. The wattage of the LED bulbs can be as low as 8 watts. Again, the incandescent A21 bulbs operate at higher wattage that can range up to 150 watts. However, LEDs are the most popular variant for their energy efficiency and durability. They use much less wattage to give equivalent lumen output than the incandescent ones.

Brightness & Versatility 

The large size of A21 bulbs allows them to spread prominent lighting in the surroundings, offering sufficient brightness. You can use them for versatile usage, including- ceiling fixtures, table lamps, floor lamps, and pendant lights. Whether it’s a large room or a small one, it meets the lighting requirement. 

Color Rendering

A21 bulbs are designed with better color rendering features. It can give off accurate color visuals of the product as natural lighting. However, the accuracy may vary based on the fixture’s quality and the bulb’s reliability. Yet, going for an A21 bulb with CRI>95 will give better color accuracy. You can use these bulbs to showcase artwork or photography. 

Common Uses and Applications Of A21 Bulb

A21 bulbs are used for versatile purposes. Among them, the most common uses of these fixtures are as follows- 

Residential Lighting 

A21 bulbs are great for general lighting in residential spaces. You can use them in bedrooms, bathrooms, kitchens, and living spaces. Besides, they are also fit for use in the garage and staircases. You can set them on each floor of your building stairs to provide sufficient visibility. Check this for more stair lighting ideas- 16 Stair Lighting Ideas With LED Strip Lights (2024).

Commercial Lighting

In illuminating offices, retail stores, and restaurants, you can use A21 bulbs. For office lighting, go for cool-tone A21 bulbs with higher CCT. This will keep the workers energetic and enhance productivity. However, for restaurant lighting, you can use warm halogen or incandescent A21 bulbs to bring aesthetic effect. As these bulbs are not energy efficient, I suggest you use lower lumens as account lighting. This will play a crucial role in creating a statement for your space decoration. To learn more about commercial lighting, check this- Commercial Lighting: A Definitive Guide.

Industrial Lighting

When lighting industrial space with an A21 bulb, you should look for industrial grains. Consider the IK rating to ensure robustness. This will protect your fixture from any physical attack in an unfavorable industrial environment. This guide will help you out: IK Rating: The Definitive Guide to get an extended idea about IK rating. Besides, IP rating is another fact to consider, especially when you are using the A21 lights outdoors. In an industrial environment, indoor fixtures might also need a higher IP rating, as many locations have to go through continuous dust, dirt, and moisture. 

Nevertheless, the fixture’s IP rating depends on its contact level with solid and liquid ingress. To get protection against solid ingress, go for IP6X; these A21 bulbs are completely dust-proof. And for water protection, choose any one between IP65-67 dispensing on the level of contact. But if the industrial area doesn’t come in contact with water, you can go for lower ratings. This guide will help you to pick the right IP rating for your A21 bulb- IP Rating: The Definitive Guide. Besides, there are some more facts to consider when lighting industrial spaces. To learn those, check this- A Comprehensive Guide To Industrial Lighting (2024).

Hospitality Industry

A21 bulbs are widely used in creating a welcoming atmosphere in the hospitality industry. You will find them in the lobby, hallway, walkway, and waiting room of hotels, resorts, and other similar spaces. They work great to add an aesthetic appeal to your space along with its functionality. Check this guide to learn more about the lighting techniques of the hospitality industry- Hotel Lighting: The Definitive Guide.  

Educational Facilities

In classrooms, libraries, seminars, and other educational institutions, A21 bulbs are used. They provide sufficient lighting to meet the visibility required for studying in classrooms. However, you should use high-color temperature fixtures or bright white A21 bulbs when lighting educational institutions. If you install a warm bulb, this will make them sleepy, and that will affect their concentration. So, in choosing any A21 bulb for such a location, choose the color temperature wisely. 

Healthcare Facilities

A21 bulbs are widely used in healthcare locations like hospitals, clinics, chambers, medical examination rooms, and similar areas. Cool lighting is used in these areas to bring a clean and neat look. However, in some spaces like patient chambers, warm lights are used to create a comfortable ambiance. To learn more about hospital lighting, check this- Hospital Lighting: Why Choose LED Lights?

Things To Consider Before Purchasing An A21 Bulb

When purchasing an A21 bulb, here are some factors that you must consider- 

Consider Bulb Technology

A21 bulbs are available in different technologies. These include- incandescent, halogen, CFL, and LED A21 bulbs. If you are looking for the best lighting, LED is the go-to option. They are long-lasting and highly energy efficient. However, they are more expensive than other variants like incandescent and halogen. But in the long run, LED lights are cost-effective as they don’t require frequent replacement and use minimal electricity to illuminate. 

Energy Efficiency 

Considering energy efficiency is essential as it concerns your electricity bills. Energy-efficient A21 bulbs consume less energy. So, even if you turn them on all day, it will not cost much on your electricity bills. And when it comes to energy efficiency, nothing can beat LED A21 bulbs. They consume 80% less energy than the transitional incandescent bulb. 

Lifespan 

The lifespan of A21 varies for the type of bulb. The LED A21 bulbs are the most durable ones that last for 25,000 hours or more. Meanwhile, incandescent bulbs last only for 1000 hours. Halogen and CFL variants are also available. The life span of these A21 bulbs is as follows- 

As you can see, LED A21 bulbs are more long-lasting, so you should consider buying LED bulbs. They will save you from the hassle of frequent light replacement. So, you can use a bulb for years. 

Environmental Impact and Sustainability

If you are concerned about environmental impact, LED A21 bulbs are the safest option. They are durable and operate at lower temperatures. Besides, they don’t contain any toxic elements and produce lower carbon footprints. In contrast, incandescent and halogen bulbs have filaments that are composed of lead, which is bad for the environment. Again, the CFL A21 bulbs have mercury, which is not environmentally friendly. They are also responsible for the greenhouse effect. So, using an A21 bulb is a comparatively greener and more sustainable option. 

Color Temperature

The color temperature of A21 bulbs plays a crucial role in mood setting. If you want to create a cozy ambiance, go for lower-color temperature bulbs that give off warm colors. These warm A21 bulbs range from 2500K to 3500k, giving a soft glow. Cool color A21 bulbs with high CCT ratings are also available. You can use them in offices, schools, colleges, and other institutions where productivity is a significant concern. However, colorful A21 bulbs are also available. These lights are a great choice for mood lighting. To learn more about light colors, check this- How To Use LED Light Colors For Different Moods?

Dimmable or Non-dimmable

The Dimmable A21 bulbs allow you to control the light intensity. You can adjust the brightness of the light as per your requirement. For instance, you can increase the intensity for better visibility when reading. Again, for relaxing in the room, dim the bulb to create a soft ambiance. In this way, you can get suitable lighting for your space considering this feature while purchasing A21 bulbs. However, these fixtures are more expensive than the non-dimmable ones. Yet, if you want more flexibility, buy the dimmable fixtures. 

Lumen Output & Wattage 

The lumen rating of A21 bulbs determines its brightness. High-lumen bulbs give off a bright light. If you want to use these fixtures for general lighting, go for a higher lumen. And if accent lighting is what you aim for, the lower lumen is ok. However, when deciding on the lumen ratings, you must examine the wattage. LED A21 bulbs can produce equivalent lumens to incandescent bulbs using fewer watts. For instance, LED lights can produce 600 lumens by utilizing only 6.6 watts. In contrast, an incandescent A21 bulb will require about 60 watts to have the same lumen. Therefore, you will get brighter light with LED A21, corresponding to less wattage consumption. 

Compatibility

Consider the bulb base to ensure compatibility with the A21 bulb. These fixtures come with an E26 base. That is, the base of A21 bulbs is 26mm in diameter. So, to install these bulbs, you must have an E26 socket. In case the socket is designed for a smaller base like E12, you can use A21 bulbs with it. However, an adapter can help you to fit the fixture. To learn more about E26 bases, check this- What Is An E26 Bulb? Here’s What You Need to Know.

Installation and Maintenance Tips For A21 Bulbs

• Before installing, make sure the power switch is turned off. This will save you from unexpected incidents like electric shock.

• When replacing a bulb with a new one, make sure the installed bulb is cool. If the bulb is glowing, don’t touch the bulb immediately after turning off the switch. Let the bulb cool down, and then touch it for replacement.

• Avoid touching the bulbs with your bare hands. Instead, use hand gloves.

• Before installing an A21 bulb, check its compatibility with the bulb base. Also, make sure the wattage and voltage requirements of the bulb match the power source. 

• Mount the bulb properly, rotating it in a clockwise direction. Avoid over-tightening; this will be troublesome when uninstalling the bulb. 

• Clean the bulb when it gets dirty. For cleaning, always use dry clothes. Using wet clothes can be risky. Besides, if the bulls are low IP rated, it will damage the fixture. 

A21 Vs. Other A-Type bulbs

Besides A21, This type of bulb can be made in many other sizes. These include- A15, A19, A23, and A25. A15 and A19 bulbs are small-size fixtures usually used for decorative lighting. You will find them in pendant lights, chandeliers, ceiling fans, lantern lights, etc. In contrast, A21, A23, and A25 bulbs are larger and can be distinguished from the mini ones. These fixtures are used for both general and ambient lighting. The main differences between these bulbs are in their diameter and length. These are as follows- 

FAQs

The Bottom Line

The medium size of A21 bulbs makes them suitable for versatile usage. These bulbs, being larger than A19 bulbs, can be used for general lighting. You can install them in your bedroom, living room, kitchen, or bathroom. These bulbs are also used in table lamps or floor lamps. Again, these A21 are also great choices for accent lighting. You can use the incandescent or halogen A21 bulbs to bring aesthetic appeal to your space. The filament used in these fixtures makes them ideal for vintage decoration. 

However, LED A21 bulbs are the best choice for performance. They last much longer than the traditional bulbs. The most impressive fact is that LED A21 bulbs can save up to 80% of energy consumption compared to incandescent bulbs. Thus, it will save you electricity bills. Besides, advanced features that the traditional one lacks are also available in LED A21 bulbs. So, when you purchase an A21 bulb, always prefer the LED ones. Yet, if you want to go for incandescent and create a vintage vibe in your space, purchase bulbs with lower wattage ratings. This will consume little energy yet produce the soft accent lighting you are looking for.