A dimmer switch gives you home lighting options without the expense of installing new lights or buying lamps. With a dimmer switch, you can have brighter lighting on a dull day, create a romantic mood for a meal for two, leave a low light on in a child's bedroom, and generally take control of the way you light a room. A dimmer switch is also a great way to cut down on electricity usage and extend the life of your light bulbs. Exchanging a one-way light switch for a dimmer switch is fairly simple DIY task. Just follow these ten easy steps:
Step 1. This is the most important step when working with electrical circuits--make sure the power to the circuit you are working on is switched off! Shut the power off at the fuse box or circuit breaker and double check that the power is off by flipping the light switch on and off.
Step 2. Use a screwdriver to remove the switch mounting screws on the existing wall plate. Gently pull out the mounting box.
Step 3. Use a neon tester to check again that the circuit wires are not electrically charged.
Step 4. Unscrew the existing wiring from the box, making sure you unscrew the ground wire last (bare copper or green wrapped), and then remove the box.
Step 5. Straighten the ends of the wires, and use your wire strippers to strip the ends again if necessary so you have enough good wire exposed to attach to the wires from the new dimmer switch. Never use a knife to strip wires.
Step 6. Identify the three wires on the new dimmer, which should correspond to the wires you unscrewed from the existing wiring--a black wire, a white wire, and the copper/green ground wire.
Step 7. Identify and prepare the wires of the same color in the electrical box--black, white, and copper/green.
Step 8. Starting with the ground wire, connect each of the dimmer switch wires to the corresponding colored wire in the electrical box. Twist the ends of the wires together using pliars, and then secure them with a wire nut. Turn until it is tight and you can't turn it any more.
Step 9. Carefully push the wires back into the electrical box, screw the dimmer switch onto the electrical box, and replace the cover plate.
Step 10. Turn the power back on and try the switch to make sure it is working.
Don't put up with too-bright home lighting any longer--install a dimmer switch, it couldn't be easier.
Sources: Electrical Basics