Q&A / 

Dimmer Switches

Dimmer switches are a nice touch. They can soften the light level in a home, save you money on your electric bill and increase significantly the life of your light bulbs. You don't believe me? Well it's true.

The electric cost savings basically parallels the amount that you dim the lights. If you dim by 10 percent, you save 10 percent. Dim the light 25 percent and you save roughly 20 percent on your electric bill. But light bulb life increases dramatically. Dim your lights 10 percent and your bulbs last twice as long! Dim your lights 25 percent and they last four times longer. This makes a big difference if you happen to use expensive bulbs, or if they are in hard to reach locations such as a two story entrance hall or a huge vaulted ceiling in a family room.

Controlling Light Intensity

To control the intensity of light you need to control the flow of electricity that causes the light bulb filament to glow. You can do that in one of two ways:

  • Change the amount of voltage that reaches the lamp or bulb
  • Control the amount of time that electric current flows to the lamp

The first method - controlling voltage - was used by early dimmers. These devices were called rheostats and autotransformers. Both of these converted the unwanted electricity into heat. They were highly inefficient.

In 1961, Joel Spira invented the first electronic dimmer switch. This device controlled the amount of time that current flowed to the lamp or the light bulb. The end result was the same with respect to light intensity but there was very little waste of energy. You see, the electricity never flowed past the switch in the first place. The electronic dimmers cycle on and off so rapidly that our eyeballs and brains can't even tell the electricity was shut off in the first place. After all, imagine having a light bulb on full blast for an hour. It produces, in that time span, a given amount of light. If you were able to rapidly turn on and off the light bulb so that is was actually only on for 30 minutes of the hour, you would use half the electricity, right? That is what new dimmers do. They just do it so well you can't tell they are turning on and off!

Installing Dimmers

It is not uncommon for a person to damage one of these electronic dimmers. They have sensitive electronic components within them that are sensitive to short circuits and voltage spikes.

The first thing you must do when installing a dimmer is to turn off the electricity to the circuit. If the circuit panel is not correctly marked so that you know the exact breaker to tip, then turn the light you wish to dim ON. Have someone in the room and have them tell you when the light goes off as you trip individual breakers off.

If the house is occupied and you do not post a sentry, you could be in trouble. I have seen a light in the on position and then a family member walk into the room and turn the switch off as the worker is going to the panel. The worker comes back up and sees the light off and thinks that they got the right breaker. WRONG! The circuit could still be energized!

The best way to do a final check is to use a voltage tester once you begin to disassemble the existing switch. Be sure the circuit is dead.

Follow Instructions

Be absolutely sure you have purchased the right dimmer for the lighting load. Pay attention to the wattage capacity of the dimmer! Not all dimmers are created equal. Get the right dimmer for the job!

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