What Are Dimmable Light Bulbs?

Dimming your lights means the light bulbs work at a lower capacity but still offer the right amount of illumination for your space. By dimming lights to 75% of their full brightness, 20% of the needed energy to light the bulbs is conserved.

Keep reading and I’ll explain everything you need to know about dimmable light bulbs.

How Do Dimmable Light Bulbs Work?

how do dimmable light bulbs work

There are different mechanisms that allow different types of light bulbs to dim by decreasing their light output. In the case of 3-way bulbs, there are 2 filaments built in that can be switched on or off.

With incandescent bulbs (more about them in a moment), the strength of the current flowing into the bulb controls a bulb’s brightness which corresponds to its voltage. A dimmer switch reduces the voltage of the current flowing into the bulb and therefore produces less light. This gives nearly complete control over the light level, unlike 3-way bulbs with fixed brightness settings.

Dimmable LED light bulbs, however, are different case and don’t work the same as I’ll explain below.

Dimmable Light Bulb Use

Dimmable light bulbs have two significant benefits:

  1. They reduce a home’s energy consumption.
  2. They allow you to customize the lighting in your space and create a more pleasing ambient mood.

Not all spaces need to be as bright as day and not all rooms need bright light at all hours. With dimmable bulbs, you’re able to reduce the brightness of a bulb at your leisure.

You can even have lights ranging from brilliant white to soft yellow, all from the same light source!

What Light Bulbs Are Dimmable?

what light bulbs are dimmable

There are several types of dimmable light bulbs, including LED, compact fluorescent light (CFL), incandescent, and halogen bulbs.

  • Incandescent bulbs are the traditional type of bulb and work by running an electric current through a filament. This causes the filament to become so hot that it glows.  These bulbs are widely compatible with dimmable lamps, though they’re no longer commercially available because they’re not very energy efficient.
  • Halogen bulbs function in a similar manner, producing light via a heated filament, but use a different type of glass and gas in their design. They’re also widely compatible with dimming lamps and produce powerful, daylight-like light, but they only last between 1,000 and 2,000 hours ‒ a relatively short lifespan for light bulbs.
  • In the case of LEDs, certain bulbs are specifically dimmable, and you can activate them with a resistive dimmer. These types of bulbs are low-watt and energy-efficient, typically boasting a lifespan of more than 20,000 hours.
  • CFL bulbs, on the other hand, are not typically useful as bulbs in dimming lamps. Using a dimmer switch will normally shut off the CFL bulb entirely. However, some CFLs do come equipped with a dimmable ballast meaning they can be dimmed; be sure to check the packaging on your bulb to see whether it’s dimmable.
Note: When shopping, it’s important to remember that not all LEDs are dimmable so make sure a light bulb’s package lists it as dimmable before you buy it. Otherwise you’ll either get nothing from the LED bulb or can even potentially cause it to fail.

How to Tell if a Light Bulb is Dimmable

  • Standard incandescent bulbs are almost dimmable.
  • You can typically assume that halogen bulbs are dimmable but you’ll need to check before buying to make sure LED or CFL bulbs types are.
  • Most of the time dimmable CFL and LED bulbs are sold with it on their packaging.

The best rule of thumb is this: if it’s not an incandescent or halogen bulb and doesn’t clearly state it is dimmer compatible on the package then it’s not dimmable. This assumption will keep you from wasting money.

Are LED Bulbs Dimmable?

are led bulbs dimmable

Not all LED bulbs are dimmable; in fact, dimmable LED bulbs use entirely different components than non-dimmable bulbs. However, dimmable LED bulbs typically come in one of two varieties: Pulse Width Modulation (PWM) and analog.

Analog bulbs control their current to either dim or brighten the intensity of the light, depending on the setting. PWM bulbs are a bit more complicated.

In general, LED lights work by cycling their lights on and off in the span of milliseconds, so even though the light bulbs seem on to the human eye, they save energy by turning off for milliseconds at a time. PWMs can adjust this cycle depending on their setting, making them appear brighter or dimmer.

For instance, if a PWM bulb dims to 50% brightness, the light is set to be on 50% of the time and off the other 50%. If you set the bulb to be dimmer, the light will be on for less time, and vice versa.

Do Dimmable Bulbs Cost More Than Non-Dimmable?

do dimmable bulbs cost more than non dimmable

Yes, dimmable LED bulbs typically cost more than non-dimmable bulbs. LED bulbs are constructed with more complex technology than standard bulbs meaning they tend to be more expensive to produce.

And while LED bulbs tend to be more costly in general their longevity and energy efficiency often more than makes up for the initial investment. There are some cases where a dimmable bulb doesn’t cost any more than a non-dimmable bulb but as a rule they usually do.

Where Can You Buy a Bulb Dimmer?

where can you buy a bulb dimmer

One of the problems with dimmable LEDs is that they aren’t always compatible with standard dimmers. The reason is because they use so little wattage that dimmer switches aren’t always able to detect them or function as intended.

This often results in the LED bulb flickering, shutting off, or working at almost normal brightness.

The easiest way to avoid this to buy an LED-compatible dimmer switch. Dimmer switches control the power and voltage to it and therefore allow it to dim as opposed to having full voltage and power applied.

LED-compatible dimmer switches are available anywhere you might buy home improvement products, including Lowe’s, Home Depot, or Amazon.

James Marshall
About the author

James is a business management professional and consultant with a former background in maintenance, repair, and hands-on projects. He enjoys DIY tasks and maintenance around the home as well as part-time writing. Read more »