What is a dimmer?

The science behind a typical dimmer is relatively simple and hasn’t really changed much. An electronic dimmer component, called a triac, turns the light on and off very rapidly – 120 times per second. The longer the triac is off, i.e. the more the lights are dimmed, the lower the light output and the greater the energy savings.

Why use dimmers?

Simple, dimming gives you control. Control your environment; set the mood for your surroundings and create the correct lighting for different tasks. Control your money; installing a dimmer saves you about 3% in energy use and that is before dimming, not to mention the increased life you will get from your light bulb. Save more by installing occupancy or vacancy sensors, eliminates “forgetting to turn the lights off.”

Where should I use dimmers?

Everywhere you have a light switch. Dimmers can’t be used on switches that run motors. That being said, there are specific dimmer controls for ceiling fans and most fans today include controls as a standard.

Can I use a dimmer on my outdoor lights?

Yes, the switch controlling the lights is most likely indoors so changing it to a dimmer is easy. Just be sure to select the correct dimmer for the lights. Many outdoor lights and transformers come with their own controls: time clocks, motion sensors and photocells or they can be added after market.

Are there different types of dimmers? How do I know which type to use?

Yes there are different dimmers for different light bulbs. Most of the time the manufacturer will include this information in their literature; as a general rule-of-thumb:

What is ganging and derating?

Mounting two or more dimmers side-by-side under a multi-gang wallplate is ganging. Fins are broken off the dimmer to fit them side-by-side in the junction box; this diminished the capacity of the dimmer. For example: a 600W incandescent with dimmer with one fin broken is now 500W and with two fins broken is 400W. It is very important to keep this in mind when calculating dimmer load.

Why is my dimmer warm to the touch?

During normal operation wall box dimmers do get warm to the touch. A dimmer is 99% efficient and the other 1% is dissipated in the dimmer as heat, this is a normal part of operation.