Fix bathroom light bulb flickering

Flickering lights can be a sign of a serious electrical problem. But bathroom light bulb flickering often is due to other issues. Let’s look at things that cause bathroom light bulbs to flicker and burn out more quickly than elsewhere in the house and things you can do to prevent it.

And yes, flickering usually does go hand in hand with reduced lifespan.

Check the simplest things first

The first thing that can cause flickering is the bulb being too loose. Let the bulb cool down enough that you can touch it comfortably. Then turn the light on, loosen the bulb enough that it turns off, and then turn the bulb just until it turns on. Then turn the bulb about one more turn. Don’t cinch it down tight, but tighten it enough to make a good connection.

The other thing you can do if isolated CFL or LED bulbs flicker is to try them out in a socket in a different room. If they flicker there, the bulb is on its last legs. If the flickering is occasional, you can continue to use it if you can put up with the flickering. If it happens all the time, it’s time to replace that particular bulb.

Sometimes one of these two things is all it takes. But in bathrooms, it may not be quite that simple.


The biggest challenge bathrooms present to your lighting system is humidity. When was the last time your bedroom mirror fogged up? Probably never. But your bathroom mirror probably fogs up every day. I’ll bet your bedroom light bulbs last longer than your bathroom bulbs too.

Humidity causes corrosion. Corrosion causes poor electrical connections. Poor electrical connections cause flickering and reduced bulb light.

An easy way to reduce humidity is to turn on the bathroom fan during baths or showers. Remembering to turn the fan on and then turn it off when you’re done isn’t necessarily so easy. You might consider installing a smart switch. Excessive humidity causes more than electrical problems. It also promotes mold growth, and causes the paint in the bathroom to deteriorate more quickly.

A cheaper alternative to a smart switch is to wire your fan to the same switch as your light.


bad light switches can cause bathroom light bulb flickering
This light switch is bad news. The terminal on top is questionable, because it’s dull. The terminal on the bottom shows burn marks, which indicates lots of arcing.

All of that humidity in your bathroom inevitably leads to corrosion on your light switch and your light fixture. I once had a bathroom whose light bulbs tended to last 2-3 months at most. When I replaced the light switch, my bulbs started lasting years. When I took the old switch out, I noticed the screws had visible discoloration.

Remember: Clean and shiny metal conducts electricity well. Dull metal conducts less well. Discolored metal conducts even worse, and perhaps not at all.

Poor electrical connections can cause another problem: arcing. Arcing causes burns, which ages the metal, causes it to conduct more poorly, which causes more arcing, so the problem compounds over time.

Replacing the light switch

stop bathroom light bulb flickering - wire loop
The first secret to good electrical connections is to loop your wire like this. It gives a secure connection and lots of contact.

So, when you replace a light switch, good form is important to prevent arcing so the problems don’t compound themselves over time.

This should go without saying but I’ll say it anyway. Shut off the power to the light switch at your electrical panel before you work on the switch or the fixture. A 115-volt shock hurts enough you can feel it, and under the right circumstances can be deadly. Don’t mess around.

stop bathroom light bulb flickering - proper wire placement
Loop the wire around the screw like this, then tighten the screw. Cut back enough insulation so no insulation touches the screw. This gives a firm, secure, reliable connection. A connection like this will seldom arc, if ever.

Bend your wire into a loop that can wrap around a screw neatly. Strip back enough insulation that the screw isn’t making any contact with insulation–only metal. Position the wire around the screw on the switch so that the open part of the loop faces the opposite direction you turn the screw. Then cinch the screw down tightly. This way you’re making a nice, secure, metal-on-metal connection all around.

If you want to really go the extra mile, smear just a dab of Noalox under the terminal before you cinch the wire down, or spray a little CRC 2-26 onto the connection. These substances enhance conductivity, reverse corrosion, and inhibit further corrosion.

Finally, wrap a turn or two of electrical tape all the way around the switch to cover the screws. This keeps the switch from arcing against a metal electrical box and also helps to keep out moisture.

Consider an occupancy switch

Another reason bulbs can burn out faster than they need to is from leaving them on when the room is empty. Some people are better about turning out the lights than others. Occupancy switches increase life expectancy, especially for LED bulbs that don’t mind being turned off an on a lot. They also save money. You can read more about my experience with Lutron occupancy switches here. I’ve been using them for more than five years and I really like them.

Checking the fixture

I see corrosion more frequently on light switches than on the fixtures, but fixtures can have problems too. There’s a little tab inside the fixture that engages the bulb. Years of overtightening bulbs can deform that tab. With the power off at the breaker box, bend the tab upward slightly. It shouldn’t be flat; it should have a 10-15 degree angle to it. Spraying a little CRC 2-26 into the socket is also helpful.

If the sockets in the fixture are discolored, it might be time to replace the sockets or just replace the whole fixture.

While you’re messing with the fixture, it’s not a bad idea to take the fixture down and check its electrical connections. The wires should be wrapped together tightly and secured with a wire nut. If the wire nut fits poorly, replace it with one that fits tightly. If the wires are discolored, snip off the ends and strip back some insulation to expose clean, fresh wire.

If the wire nut comes in contact with insulation, strip back a little more insulation. Also make sure the wires are twisted together underneath the wire nut. If you just hold the wires together and secure them with a nut, it will work, but a twisted-together connection works better.

Twist the wires together, cinch down the wire nut, then wrap a little electrical tape around the ends to hold the wire nut in place and seal out moisture.

Treating your bulbs

This may be a bit extreme, but I treat my light bulbs when I replace them. I put a dab of No-Ox-ID A Special on the bulb threads and on the end when I change a bulb. Just a dab. If you can see it, you put too much on. The No-Ox-ID A Special helps reverse any corrosion that might be on the socket and prevents corrosion on the bulb or socket. It works better than the stuff you can find in the hardware stores and a one-ounce container will last years.

It’s a bit extreme, yes, but it helps bulbs last longer. LED bulbs aren’t nearly as expensive as they used to be, but I still prefer for them to last as long as possible.

If just one of your light bulbs flickers, treating it with some No-Ox-ID A Special isn’t a bad idea. The bulb may be getting a poor connection or it may be on its way out. The No-Ox-ID A Special will increase its service life, and increase the service life of its replacement.

The bulbs you use matter

LED bulbs do last longer in bathrooms than other types, given the extreme conditions and the frequency people tend to turn them on and off. Even if you don’t use LED bulbs, look for the longest-life bulbs of the type you prefer. Cheaper bulbs tend to develop problems faster, regardless of type.

I also prefer to use a light fixture that hides the bulb, rather than a bar-type fixture that has to have globe bulbs to look good. Finding quality globe bulbs is difficult, and they cost a lot more than regular bulbs.

Bathroom light bulb flickering cured

It takes a little work and usually a little expense to cure bathroom light bulb flickering. But it’s still a project you can easily tackle in an afternoon. It eliminates an annoyance, improves safety, and saves you money. All three of those are good things.

Leave a Reply