How To Install A Dimmer Switch

By Mary Jo Bowling, Originally Published in Houzz

Today's dimmers are sleeker and more efficient.

According to electrician Britt Scott, if you haven’t flipped the switch to a dimmer, it’s time to do so. “A dimmer switch can change your whole life,” claims Scott, who owns Lady B Electric in Santa Rosa, California. “Nothing else can set the mood in your home like a light control.”

Why: Lighting designers have known this for years: The light level in a room sets the mood and enhances dining and entertaining. Being able to control the lights can also make a room flexible: If you want to relax, you can turn them down. If you need to work, turn them up. 

Who to hire: Installing one simple dimmer switch could be a DIY project. Installing more or an entire lighting system is a job for an electrician.



Cost: $30 for a basic dimmer switch from the hardware store; roughly $1,000 for professional labor and materials to install dimmer switches throughout a home.

How: “You can replace an existing switch with a dimmer by yourself if it is a 120-volt, simple up-and-down control,” Scott says. “I would not advise a homeowner to take on more than that.”

1. Carefully read the instructions that come with the new dimmer switch. “The biggest mistake people make is not reading the instructions,” says Scott. “I’ve been doing this a long time, and even I carefully read all the instructions with a new piece of equipment.”

2. Disconnect the power at the circuit breaker and flip the light switch to ensure that the power is off.

3. Unscrew the switch plate and remove it. It’s a good idea to make sure the wire isn’t carrying any current; use a noncontact voltage detector to check.

4. Remove the screws holding in the old light switch and gently pull it out of the wall. The switch either will be held by wires wrapped around connector screws at its sides, or will have wires coming out of it that are connected to wires coming out of the wall and capped with wire nuts (they look like marker caps).

5. If the wires are looped around connector screws, undo them, snip them and strip them. Follow the package instructions to loop the ends of the wire around the connector screws on the new dimmer switch and tighten them with a screwdriver. If the unit is installed wire to wire, remove the wire nut and untwist the copper strands, then snip and strip the wires coming out of the wall. Following the package instructions, use pliers to twist the new dimmer wires to the wires coming out of the wall. Cap them with a wire nut.

6. Tuck the switch into the box, secure it with screws and reaffix the switch plate. Turn on the power and turn the lights down low.

“If it doesn’t work or you feel unsure at any point in the process, contact an electrician,” says Scott.

Typical project length: A DIY project with a single switch can take an hour. For a pro to install dimmers throughout the house, it could take as little as four hours.

More: “I recommend buying the best dimmer switch you can afford. The more expensive ones tend to last longer,” says Scott.

January 8, 2014