why do light bulbs burn out

What Causes Lightbulbs to Burn Out?

In a perfect world, lightbulbs would never burn out…but sadly our world isn’t perfect. While not as popular as they once were, incandescent bulbs have a lifespan of around 900 hours. Based on a usage of eight hours a day, a bulb should last roughly about four months. Compact fluorescent bulbs are supposed to last much longer, but this is not always the case. Even our beloved LED bulbs will eventually need replaced. But sometimes it seems like lightbulbs burn out more quickly than they should. If you’ve replaced bulbs recently and the lifespan doesn’t seem to be all that it should, the cause may be the fixture itself or another problem entirely. Here are a few things you may want to check before throwing out another bulb.

High Voltage in the Home 

If the supply voltage to your home is higher than it should be, lightbulbs will burn brighter, thus burning out much faster. You can test for voltage at a standard (120-volt) electrical outlet, using a multimeter or a voltage tester. Be sure you know how to do this safely because the power will be on. If a test reveals a voltage higher than 125 volts, contact your electrician to look at the problem.

Excessive Fixture Vibration 

A good example of this is a shaky ceiling fan with a light fixture. This happens when a light fixture becomes unbalanced. This vibration jiggles the filament in the bulb and leads to a shorter bulb life. (This is why garage door lightbulbs tend to burn out quickly!) You can try a rough service bulb to correct this problem. These bulbs have heavy-duty filaments to withstand vibration better.

Depressed Socket Tab 

The little metal tab at the bottom of a light bulb socket is the “hot” connection that delivers electrical current to the bulb. If the socket gets pushed down too far, it can fail to contact the bulb. To fix this problem, simply unplug the lamp or turn off the power to the fixture, use a wooden popsicle stick to bend the tab up about 1/8 inch, turn the power back on, and test it.

Bad Bulb 

Compact fluorescent (CFL) bulbs are notorious for going bad before their time. CLFs are believed to have a 10,000-hour lifespan, but if you’ve had them you know this isn’t the case! The answer here is to switch to LED bulbs. They’re more efficient, last longer, and don’t contain potentially dangerous mercury like CFL bulbs do.

Flickering Bulb 

Bulbs flicker when they’re loose in the socket. Simply tighten the bulb to correct the problem. Another issue could be a loose wire connection. Turn off the power and check the connection on the fixture. Contacts in the center of the socket can get worn or corroded, and if this is the culprit, simply replace the socket or the fixture.

Tripped Circuit Breaker or Blown Fuse 

A tripped breaker or blown a fuse can be a major culprit of bulbs not working. The fixture cord may be shorted, a plug could be defective, or the light socket may be shorted or defective. In any of these cases, replace the defective parts before resetting the breaker or replacing a fuse.

Overheated or Burnt Bulb 

Using a bulb with a wattage that’s higher than the maximum rating for your light fixture creates excessive heat, reducing the bulb life and potentially melting the insulation on the fixture wiring. Prevent problems by using the appropriate bulb wattage. Energy-efficient bulbs (such as LEDs) have much lower wattages than standard incandescent bulbs while producing an equivalent amount of light.

Recessed Light Problems 

Recessed light fixtures often have housings that extend into the attic. Some fixtures are designed to be covered with attic insulation, but some fixtures must have the insulation held back by at least 3 inches, to prevent overheating of the fixture. Overheating causes bulbs to flicker or burn out early and are also a fire hazard. If your fixture is not rated “IC,” it should not be covered with insulation. You can build a box around the fixture housing to allow for the appropriate space.