How to Install a Dimmer Switch

Installing dimmers for your lights is a great way to set the mood, and it only takes a few minutes. And once you install one, you will want them for every light in your house. Besides looking really cool, they’re a god-sent on your eyes during that 2 a.m. snack.

Dimmers are a great way to save money since they drastically increase a bulb’s life while reducing electric use. Citing a source within the industry, if an incandescent bulb is dimmed only 10%, you will double the bulb’s life and save 5% on electricity. Dimming it 50% extends the bulb’s life 20 TIMES and saves 25% on electricity!

Use a Single-Pole Dimmer to replace the switch that controls the light(s) from a single location. Use a Three-Way Dimmer to replace a three-way switch.

Step by Step

1. Turn off power to the circuit, Be sure to test to make sure it's off. Unscrew the plate covering the switch and the screws holding the switch in its outlet box. Gently pull the switch out of its box.
2. Disconnect the old switch by unscrewing the wires that had been attached to it. Straighten those wires and, if necessary, snip the ends and strip the wires afresh.
3. Connect the dimmer. Most dimmers have two non-color-coded wire leads instead of terminals. Most don't have a grounding wire. Pair the dimmer leads with the house wires, one to black and the other to white (or you may find a white wire marked black).

   If you're replacing a three-way switch with a three-way dimmer, before you disconnect any wires, note which wire attaches to each switch terminal. The easiest way to keep things straight is to attach a piece of masking tape to each wire and write, on the tape, what that wire was attached to. Attach those wires to the corresponding traveler terminals of the new three-way dimmer so they match the wiring of the old three-way switch. (Don't worry, it's easier to do than to explain.)

   Splice the wires with the twist-on wire connectors supplied with the dimmer.

4. Fold wires back in the box by pressing evenly on the dimmer. Screw the dimmer to the outlet box, replace the cover plate and then press the dimmer dial down into the shaft of the dimmer. Turn the power back on, and you're ready for business.

Buying Advice
Make sure to get a dimmer that has a wattage rating higher than the total wattage of the bulbs being used. If a dimmer is controlling more bulbs than designed, you may hear a faint hum. If that is the case, change it to a heaver filament, rough-service type.

Safety
When controlling a fluorescent light, receptacle, or any appliance with a motor or transformer (i.e. low voltage lights), NEVER use an ordinary dimmer. Those devices are set to perform at certain speeds and may overheat and get damaged if forced to run more slowly. You may destroy the dimmer in the process too. Fluorescent lights require three-wire cables and expensive dimmers.