Lightbulbs 101

Choosing the right lightbulb can be more complicated than you may think. Here's what to pay attention to when selecting a bulb.

While changing a light bulb may seem like an easy chore, selecting the right bulb for your light fixture may be more involved than you think. Here is a simple guide to understanding the basics of lightbulbs to make sure you choose the right bulb for the right job.


Most everyone is familiar with a lightbulb’s wattage. The wattage is a measure of the amount of energy that the lightbulb is able create. When replacing a lightbulb, be sure to look at the amount of wattage for the fixture. Most fixtures can support between 40 and 120 watts. Select a bulb that is equal to, or lower in wattage than the fixture. Using a bulb with a higher wattage than the fixture can support is a major fire hazard.


Unlike wattage which measures energy, lumens are a measure of how much light that a lightbulb can emit. The larger the space that you wish to light, the higher the lumens (1000 or greater) you will need. Choose bulb with lower lumens for areas that require less lighting.


Bulbs can come in a variety of shapes and sizes. When replacing a bulb, you will want to ensure that the bulb you select fits the fixture. A standard bulb in North America has a thread measure of E26, which means that the threads’ external measure is 26 millimeters.

Life Expectancy

Light bulbs can vary in life span. Life expectancy is generally based on three hours of use per day. You will want to choose longer lasting bulbs for frequently used lights. LED bulbs have the longest lifespan, followed by compact fluorescent bulbs, halogen bulbs, and incandescent bulbs, which have the shortest life expectancy.

Light Appearance

Light appearance refers to how “warm” or “cool” the light will appear. Warmer lights are more yellow in appearance, while cooler bulbs will look bluer. Light appearance can affect the perception of colors in a room.

Energy Efficiency

The energy cost of the lightbulb will tell you how much the bulb will cost in electricity over its lifetime. The more energy efficient the bulb, the less electricity that is needed to power it, and the less you will spend on your electric bill each month.


Never throw bulbs containing mercury in the garbage. Be sure to dispose of bulbs with mercury in the appropriate manner.