A dimmer switch is great for taking control over the way a room is lit. It gives you the ability to make subtle changes in light levels—to set the mood in a dining room, lower the levels in a child’s room, or even give you flexibility with outdoor lighting.

In addition to these aesthetic benefits, a dimmer also has a couple of important, practical pluses. First, a dimmer saves energy by allowing you to tailor electricity usage very precisely, eliminating waste. It also extends the life of most lightbulbs because it minimizes or eliminates the “filament shock” when you flip on a conventional light switch.

Replacing a conventional light switch with a dimmer switch is a relatively simple task, even if you’re only a moderately experienced do-it-yourselfer. (Note: If you intend to use fluorescent or LED bulbs in the lighting circuit, you will need a dimmer rated for fluorescent or LED.) To buy dimmers, see Dimmer Switches.

dimmer switch
Dimmer slowly raises and dims light level to brightness set by small slider. Lutron

A dimmer switch can cause a lightbulb’s filament to vibrate, creating a buzzing sound when the light is on a less-than-full setting. You can buy a new dimmer that’s designed not to buzz and replace the switch, but before you do try replacing the bulb with a “long life” lightbulb that has a sturdier filament and is rated 130 volts instead of the far more common 120 volts.

Just remember the cardinal rule: Always shut off the power to an electrical circuit before working on it. Turn off the circuit breaker at the electric service panel, and then refer to the following step-by-step procedures:

1 Use a screwdriver to remove the wall plate. Then unscrew the switch mounting screws.

Remove the wall plate and unscrew mounting screws. ©Don Vandervort, HomeTips

2 Grasp the switch by its flanges and gently pull it straight out of the mounting box. With a non-contact circuit tester, double check to make sure the circuit wires are not electrically charged.

Pull the switch out by it’s flanges. ©Don Vandervort, HomeTips

3 Unscrew the wires from the switch terminals. If they are poked into holes in the back of the switch, use a small screwdriver to release them. Straighten the ends of the wires, or, if possible, snip them off and strip the ends again.

Unscrew the wires from the switch terminal. ©Don Vandervort, HomeTips

4Use lineman’s pliers to twist the bare end of the green ground wire together with the bare copper ground wire in the box. Then use a wire nut to further connect the dimmer’s ground wire to the circuit’s bare copper or green ground wire.

Connect the switch’s ground wire. ©Don Vandervort, HomeTips

5 Connect one of the dimmer’s black wires to each of the two black wires in the box using wire nuts.

Connect the light switch wires. ©Don Vandervort, HomeTips

6 Make sure the connections are tight, and then carefully push the wires into the box, leaving room for the dimmer. Position the dimmer, and screw it to the mounting holes in the box.

Double-check the connections and replace the switch. ©Don Vandervort, HomeTips

7 Replace the faceplate. Turn the power back on at the electrical panel, and then try out the switch.

Replace the faceplate. ©Don Vandervort, HomeTips
Author Image
About Don Vandervort
An avid builder and remodeler, Don Vandervort has developed his expertise for more than 30 years, as Building Editor for Sunset Books, Senior Editor at Home Magazine, author of more than 30 home improvement books, and writer of countless magazine articles. He appeared for 3 seasons on HGTV’s “The Fix,” and served as MSN’s home expert for several years. Don founded HomeTips in 1996. Read more about Don Vandervort