There are plenty of reasons to change out a lightswitch, from aesthetics to function, and it's a good general skill to have if, well, you live in a home with light switches. The best thing is it's surprisingly easy to do, even for someone with little (or no) electrical experience, and can be done in less than 10 minutes. Click below the jump to see our photo-illustrated how-to.
These directions are for a single switch that controls one or a set of lights. If you're working with a three-way switch (where two switches control the same light) these will not apply.
Tools needed: Screwdriver, new light switch
Step One: Turn off the breaker or fuse to the switch in question. If you're not sure which breaker controls the switch, turn off the main to be safe.
Step Two: Remove the plate cover

Step Three: Unscrew the switch from the box.

Step Four: Pull out the switch and assess the situation. It should have two coated wires coming from it. If your switch is grounded, it will have a third wire, this ground wire is usually an uncoated copper wire.

Step Five: Remove the old switch from the wires. Depending on the type of switch the wires will be connected differently. Pay attention to how they're connected as you'll most likely want to connect the new wires the same way.
Step Six: If you have a ground wire, connect it to the new switch - it connects to the green screw at the bottom of the switch

Step Seven: Connect the wires to the switch. In a standard one way switch, the order of the wires doesn't matter. The wires will either connect by being pushed into two holes in the back of the switch, or being side mounted to the copper screws on the side of the switch. Make sure the connection is solid.

Step Eight: Screw the new switch into the box. If you're in an older house, the electrical box may be made of out metal. If this is the case, be very careful that no exposed wires (with the exception of the ground) are touching the metal box. Make sure it's right way up - when it's flipped down it will say "OFF" if it's the right way or "NO" if it's upside down.

Step Nine: Put the plate cover on

Step Ten: Turn the power back on and test your new switch. If it doesn't work, chances are you didn't make a good connection with one of the wires, go back to Step One and start again.
Enjoy your new switch!
How about step 1.5? Buy a voltage tester from HD for a few bucks and check that there really are no live wires before sticking your fingers in the junction box (in particular if you decide to hold your screw driver by the metal part, rather than the insulated handle).
view particlebored's profile
This is a great post. Thanks to Particlebored on the safety tip. Whe it comes to do it yourself with electricity, you can never be too safe.
view Seaside's profile
Thank you all - coincidentally this was something I was about to embark upon and it was good to get a quick refresher. Always something serendipitous about Apartment Therapy!
view Marco's profile
Glad you posted this... People need to be less afraid to tackle this fairly simple project.
Just a note... There are several parts of the country where local code requires metal boxes even in new construction. (I had an electrician tell me that it is illegal to sell plastic boxes in Chicago.)
view Devyn's profile
Actually, avoid HD's voltage testers, they are complete shite. I returned a brand new one only to have the kid at the returns counter tell me it was one of their most common returns. I got one at OSH that works much better.
view dollarvines's profile
A city building inspector told my building codes class that you technically need to pull permits for this type of electrical work in California. Safety First!
view slipperymarshmallow's profile
One of the best $30 home repairs we did in our current house was replacing the bedroom light switch with a touch-sensor one that has a dimmer built-in. I've actually replaced regular light switches with dimmers in rentals, because they make so much difference, and it's such an easy fix. (As well as it's nice to replace all the yellowed ivory ones with crisp, clean white switches.) This really is a simple home fix that more people should try to take on (carefully, since playing with electricity can end poorly - as a roommate once told me, now is not the time for joking around about being electrocuted).
view kls987's profile
so you can also use this same process to change out a regular on-off switch for a dimmer or click-level switch?
i'm hoping so!! i really want my bedroom overhead light on a dimmer!
view lizkid's profile
Step Zero: Make sure you do this during daylight hours.
Surprisingly it makes a difference :P
view That70sHeidi's profile
And if the numbskull who painted the room before you moved into the place painted the plates (or outlet plates, or AC vents, etc.) to the wall, use a razor and gently trace around the switchplate so you don't pull off more hunk of wall than you need to during extraction. You don't have to just paint around or (eep) over those fixtures, and it's definitely worth the few extra minutes to remove them!
view OneWallKitchen's profile
Technically, this requires a permit in most cities. Which is a total farce. Land of the free, indeed!
By the way, getting shocked in the US is not really a big deal. Growing up we would test by smacking the back of our hand against a potential live wire. It hurts, you get burned but unless your pacemaker explodes, you'll get over it. Not so much in Europe...
view Easyenough's profile
My dad's an electrical contractor turned general contractor turned building inspector, and when he came to visit last time I had several dozen switches and outlets waiting for him to change out (I was swapping beige for white ones.) He kinda rolled his eyes that I hadn't just done them myself. I knew how after watching him do it for years, but I told him I'd read that you needed to pull permits for it. He said technically, yes, but very very few people get them, and at least where he worked they were fine with that ... as it was a lot of paperwork/effort for a small job that (he felt) most homeowners should just do themselves in a few minutes.
view ridge_van_winkle's profile
Oops, he says technically yes in SOME places, but it's rarely enforced anywhere. I don't know if they're necessary in NY or not. Anyone here know? What about for changing light fixtures? That's something he thought I should do myself also and I'd planned on swapping out some of my ugly flush mount ceiling lights.
view ridge_van_winkle's profile