I paid an electrician $150 to install a dimmer switch three years ago. Watched him do it. Realized it took him 15 minutes and the switch itself cost $12. I have installed six more myself since then.

If you can use a screwdriver and follow the instruction to turn off the breaker, you can do this.

What You Need

• A dimmer switch ($15-25 at any hardware store)
• A flathead and a Phillips screwdriver
• A voltage tester (non-contact, $10 — do not skip this)
• Wire nuts (usually included with the switch)

Step by Step

1. Turn off the breaker. Find your electrical panel. Flip the breaker for the room you are working in. If you are not sure which one, flip the main. Label it if it is not labeled — future you will appreciate this.
2. Test that the power is off. Flip the existing switch. If the light does not turn on, good. Now use the voltage tester on both wires behind the switch. If it beeps, the power is still live — go back to step 1.
3. Remove the old switch. Unscrew the faceplate. Unscrew the switch from the box. Pull it out gently — the wires are attached to the back.
4. Take a picture of the wiring. Before you disconnect anything. This is your reference in case you get confused.
5. Disconnect the old switch. Loosen the terminal screws and pull the wires off. There will be two black wires (or one black, one red) and a green or bare copper ground wire.
6. Connect the dimmer. Match the wires — black to black, green to ground. Twist the ends together with a wire nut, then screw the nut tight. Tug test each wire gently to make sure the connection is solid.
7. Screw the dimmer into the box and attach the faceplate. Turn the breaker back on. Test it.

What Could Go Wrong

If you have a three-way switch (two switches control one light), you need a three-way dimmer — they cost a few dollars more but the wiring is similar. If your house is older and the wires are fabric-wrapped or aluminum, call an electrician. The $150 is worth not burning your house down.