Is This Bulb Dimmable?

In a perfect world, every bulb’s light can be lowered to the exact light level you want. But reality involves more trial-and-error than many of us have time for. A bulb’s dimming ability shouldn’t be the cause of a long-suffering sigh. The following tips should help you make better decisions on what type of light source to use and how to dim it.

Is This Incandescent Bulb Dimmable? Yes.

We begin with one of the oldest and the easiest light sources to dim: incandescent bulbs. The answer is yes, all incandescents are dimmable. They have the largest controllable dimming range from 100% full light, all the way down to 0%. Incandescents produce light by allowing an electric current to flow through a metal filament surrounded by inactive nitrogen and argon gas. The current heats the filament and produces light at the same time. Reducing the current (i.e. reducing the voltage), which is what a standard dimmer does, produces a little less light but doesn’t prevent the incandescent from working. The lower voltage will also benefit your incandescent bulbs, causing them to outlast their typical 1,000-hour life span.

Is This Halogen Bulb Dimmable? Yes.

Surprise! All halogen bulbs are dimmable; this includes xenon and krypton bulbs as well. A halogen bulb operates the same way an incandescent bulb does. However, halogens have a quartz capsule and some additional gas from the halogen family that slows down the burning process of the metal filament, allowing them to last twice as long as incandescents. Your incandescent hall light and the halogen bulbs in your track lighting can share dimmer without a problem.

While dimming makes incandescents last longer, your halogen bulb may come to a premature end. When a halogen bulb is dimmed down to 20%, the gases around filament begin to build up on the capsule glass instead. Then the bulb begins to operate as an incandescent, leaving the filament to overheat and burn out.

Is This CFL Bulb Dimmable? Maybe.

Only some CFL bulbs are dimmable. The package or bulb should say if it’s dimmable and tell you which dimmer switches are compatible. You may get varying results with different CFLs and their compatible dimmers. Sometimes the CFL will only dim down to a certain percentage, about 10-40% of full light levels, before the light cuts off completely. Now you could be lucky and your standard incandescent/halogen dimmer will work with your CFLs as well. To be absolutely sure, you should also make your dimmer switch is rated to handle CFLs. You’ll quickly find out if you have a non-dimmable CFL since the bulb won’t light up when you apply a lower voltage.

Is This Fluorescent Tube Dimmable? Most Likely.

The short is answer is yes, all linear fluorescent tubes are dimmable. However, before you start picking wall plates for your new dimmer switch, you need to check the ballast first. In order to dim fluorescent tubes, you need a dimmable fluorescent ballast installed. Today, most dimming ballasts are electronic and are efficient enough to dim the lights down to 1%. You should also confirm that the dimmer switch can handle fluorescent lamps, which is different from being rated to handle CFLs. This same advice applies to plug-in 2-pin and 4-pin CFL lamps.

Is This LED Bulb Dimmable? Maybe but You’re Going to Need a Special Dimmer.

Like CFLs, you need to check if your LEDs are dimmable. That goes for all LED bulbs, from MR16s and decorative chandelier bulbs to T8 bulbs and lamps for your garden post. LEDs are not able to be dimmed by a standard dimmer switch the same way. Since LEDs use a small fraction of an incandescent’s normal wattage consumption, your dimmer switch may not register the load. That means your light may stay on without any perceivable dimming, flicker like its auditioning for a horror movie, or just shut off completely. To avoid those situations, choose an LED-compatible dimmer switch.

Lutron Maestro dimmer switch with wallplate

LEDs have a wide dimming range, commonly dimmable down to at least 10%, sometimes able to dim down to 1% of full light levels. A compatible switch should take care of most LED dimming problems, but not every LED dimmer switch is right for every LED bulb so be sure to check the compatibility chart. Occasionally, a dimmer switch will only be able to dim an LED to a certain percentage, like 30% of full light instead of the promised 10%. In fact, regardless of what type of lights you have, you should read the bulb and dimmer’s features before making a purchase.

Did we clear up your dimming debacle or do you still have questions? Allow us to shine a spotlight on your lighting mystery by commenting in the area below. Find more ideas and advice on our Facebook, Twitter, LinkedIn, or Pinterest. If that spec sheet looks like gibberish, you can also contact our knowledgeable 1000Bulbs.com staff at 1-800-624-4488, Monday through Friday from 7am to 7pm CST, for more help finding everyday lighting solutions.