How To Install a Dimmer Switch

updated Jul 18, 2020
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(Image credit: Rachel Wray Thompson)

Dimmer switches are great, not only do they provide opportunity for mood lighting and ambiance, but also save money due to reduced power usage. Almost all the lights in my home are on a dimmer switch, except for the bedrooms, where we’d actually like to have them the most. Having our bedroom lights on dimmers would prevent my fiance and I from disturbing each other during mornings and the middle of the night — and it will save our eyeballs the shock of bright light after hours of darkness. So we finally set to it, and changing the switches was easy and inexpensive, and took less than 15 minutes! Find out how to do it yourself, after the jump.

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How To Install a Dimmer Switch (Image credit: Rachel Wray Thompson)

What You Need

Dimmer switch — there are a variety of styles (and accompanying prices ranges), we went with the toggle type, because we can’t stand the knob kind as the others in our house are always falling off!
Dimmable light bulb — unless you still use incandescents, you will need to switch our your fluorescent bulb with a dimmable version, which is now widely available in hardware stores and online.

Small flat head screwdriver
Phillips head screwdriver
Electrical Tape (optional)


1. Turn off electricity and power to light switch you are changing.

2. Using flat head screwdriver, remove existing switch plate. Turn screws attaching switch to electrical box counterclockwise and gently pull out switch from wall.

3. Observe the wiring to determine whether the switch is a 2-way type (also known as single-pole, meaning only one switch controls the light) or not (meaning more than just this one switch is controlling the light). If it is a 2-way, then only two wires will be connected to the switch, if there are three wires then it is at least a 3-way switch, and you will see three different wires, one of which will be connected or labled as such. If this is the case you will need to use a specified 3-way dimmer and install as such.

4. Disconnect wires from from terminals existing switch.

5. Reconnect wires to new dimmer switch in the same manner as they were connected to the old switch. Turning clockwise, use a phillips head screwdriver to loosen and tighten the terminals as needed.

6. Put dimmer switch back into electrical box, and using the flat head screwdriver mount the switchplate back to wall.

7. Turn on electricity and power to light switch that was changed.

8. Adjust dimmer to desired lighting level and enjoy!

Additional Notes: Always follow the manufacturers instructions for detailed and specific installation, and when in doubt contact an electrician. If you have made the leap to LEDs, you will need to have an electrician perform the installation, or at the very least a hardware store employee help you determine what type of dimmer will work for your LED, as these are much more complicated and have not been standardized yet in the lighting industry.

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(Images: Rachel Wray)