What Is A 3-Way Light Bulb?

Looking at the most common light bulbs for your home you might have come across 3-way light bulbs. These are special light bulbs that produce three different levels of light. Let’s find out more about the pros and cons of 3-way bulbs.

What Are 3-Way Light Bulbs?

A 3-way light bulb is a special kind of light bulb with three settings: low, medium, and high. This bulb is designed to give you more control over the level of light in a room, making it a versatile option for everything from task lighting to reading to general illumination.

The versatility of the 3-way light bulbs makes them a great option for bedroom or table use. For instance, use low light if you’re watching TV and need dim light for a better watching experience. Use medium light in tasks requiring more focus, such as sewing. If you want the brightest possible lighting, go for the high light output.

Most 3-way lighting setups use a bulb with a standard screw base (E26) and either 30/70/100 or 50/100/150 watts. This setup allows switching between different light levels,

Some larger floor lamps use a PS25 bulb with a Mogul screw base (E39). They require 100,200 or 300 watts to cast more light on the wall and ceiling.

woman screws 3-way bulb in floor lamp base
A 3-way bulb brings three different brightness levels for your lamp

What Are the Different Types of 3-Way Light Bulbs?

There are two main types of 3-way light bulbs; 3-way incandescent light bulbs and 3-way LED light bulbs.

3-Way Incandescent Light Bulbs

3-way incandescent light bulbs consist of two filaments(low and medium wattage) that operate at full voltage.

Low-wattage filaments can be 30W, 50W, or 70W. While medium-wattage filaments have 70, 100, or 200 watts.

When a 3-way bulb gets power, it supplies electricity to the low element first. Then, the power moves to the medium filament and eventually to both simultaneously. The overall wattage is the total power of the two filaments.

3-Way LED Light Bulbs

LED 3-way light bulbs use the same socket as incandescent lamps. However, the total wattage doesn’t count in the same way as in incandescent lights because they don’t work in the same manner.

3-way LED light bulbs are slowly replacing traditional incandescent bulbs. Why? For one, they’re much more energy efficient. And even though they’re more expensive, they’ll save you more bucks upfront as they last longer and don’t spike up your electricity bills.

Moreover, they’re environmentally friendly and don’t need a specific disposal method. There are also many light types, such as soft white light, traditional yellow light, and bright white light.

LED lights also turn on in no time, unlike CFLs which require time to warm up and produce less heat, which makes them a safer option around kids and pets.

3-way bulb with LED technology
3-way LED bulbs look the same as standard LED bulbs

Differences Between 3-Way Light Bulbs and Dimmer Switches?

Many users confuse the 3-way light bulbs with dimmer switches. They typically aim for the same purpose; switching between different light levels. However, they are not the same.


As we mentioned, 3-way light bulbs have two filaments controlling brightness levels. You either turn on filament 1, 2, or both.

On the other hand, dimmable light bulbs operate by a special electric circuit that allows you to adjust the brightness.

Changing Brightness

In dimmer lights, you use an external switch or remote control to send signals to the dimmer to adjust how much power goes to each LED. That way, you switch between different brightness levels gradually.

To simplify it, in 3-way light bulbs, there’s no gradual change in brightness. While controlling dimmable lights is like adjusting the volume of your stereo. You gradually increase or decrease the lights using a switch or remote control until your reach your desired light level.

Benefits Of 3-way Light Bulbs

With a 3-way light bulb, you can choose between three lighting options: low, medium, and high. This makes them the perfect choice for any situation.

  • Want to read in bed without disturbing your partner? Low light will do the trick.
  • Need to do some work but don’t want to blind yourself? Medium is the perfect setting.
  • In case you need to get things done fast, high is the way to go.
  • You can always opt for 3-way LED lights, which are extremely energy efficient in the long run. Some products operate for up to 25,000 hours.
  • 3-way light bulbs are usually easy to install by yourself, so you won’t need to pay for a technician to install them.

What to Look for When Buying 3-Way Light Bulbs

If you’re out there looking for a 3-way light bulb, there are some factors you need to consider before your purchase.

Size and Shape

Light bulbs come in various shapes and sizes, and 3-way light bulbs are no exception. Most light bulbs used in U.S. households are A19 bulbs with an E26 base.

To explain more, the letter A refers to the shape of the bulb, which is arbitrary. The number 19 refers to the bulb’s size. While E26 means the bulb has a 26mm Edison Screw base.


The color rendering index (CRI) is a metric that assesses the distinguishing characteristics of a light source. It evaluates how your light source shows the color of surrounding objects in comparison to incandescent light or natural sunlight.

If you’re shopping for new light bulbs, check their CRI score. It would be best to aim for light sources with a CRI score of 80 or more.


The most common 3-way light bulbs are either CFLs or LED bulbs. 3-way LED bulbs are usually the better option. That’s because they produce less heat, save more energy, and don’t contain mercury, so they’re much safer.

How to Install 3-Way Light Bulbs

Installing a 3-way light bulb is easy and only takes a few minutes. The best part is that you don’t need special tools beyond your regular screwdrivers. Here are the steps:

  1. Start by turning off the power at the circuit breaker or on the wall switch. This will ensure you don’t shock yourself while replacing the bulb.
  2. Carefully unscrew the existing light bulb and remove it from its socket. Make sure to note how it was positioned before removing it so you can reinstall the 3-way in its original position.
  3. Next, insert the new 3-way light bulb into the socket and twist it clockwise until it locks into place.
  4. Finally, turn on the power again and test out your new 3-way light bulb to make sure it’s working properly.