When you are out shopping for LED lightbulbs you are going to notice a few key terms:

• Watts (W)
• Lumens (LM)
• Base Model

Brightness

Watts measure the “power” of a lightbulb. For decades, besides the people mainly chose lightbulbs by wattage (25W means 25 watts and 100W means 100 watts). Before the world of LED’s, a lightbulb’s wattage was the most important number. Most lamps will specify a maximum wattage, and using anything over would pose a safety concerns from overheating.

Wattage still matters but because LED’s are much more efficient and can vary more with its efficiency, we cannot and shouldn’t look at watts anymore. A lightbulb’s lumens rating is more helpful.

Lumens is the measurement of how bright a bulb is. Technically, it’s the total light output of the bulb that can be seen by the human eye. A lightbulb’s brightness can start out as low as 200 to over 1,000 lumens. Integral LED have two great charts to help you gauge the proper brightness.

If you still think in “old lightbulb thinking”, i.e. you think in watts, here’s a chart that shows you about what the brightness equivalent is:

Generally, we Americans are used to different brightness for different rooms. Here’s one way to figure out what is the total lumens you need for a room in your house. First, look at the chart below to see how many lumens you need per 10 square feet in the type of room you are buying for. For some room types, you will see two versions where one is marked as “(Task)”. “Task” just means you are installing bulbs in fixtures meant to light up the room when you are doing something, e.g. cooking or cleaning, versus just for comfort. Pretty much, you want the place twice as bright when you are concentrating on something.

For example, if you have a kitchen that’s about 20 sq ft and you’re installing bulbs for fixtures that are turned on when the kitchen is in full use, you want your bulbs to add up to 1,400 to 1,600 lumens.

Physical Fit

Once we get the brightness down, the next step is to make sure the lightbulb will physically fit into the lamp or fixture.

The base model is the type of plug or “screw in base” of the lightbulb. LED bulbs themselves are really small, and you are getting many of them, so they can be arranged into any shape and mounted onto whatever base that’s convenient. For example, chandeliers usually use the E12 base: however, it is best to take out the old light bulb and look on the base to confirm.

Fun Fact: Did you know the “E” in the base model stands for “Edison” who was the inventor of the screw base light bulb?

Lastly, make sure the lightbulb’s size and shape will fit inside the confines of where you are installing the bulbs. LED bulbs come in various shapes and sizes, so sometimes this can be tricky.

Color “Temperature”

People usually have different preference for the color of the light. The color of light is sometimes referred to as “color temperature,” which is misleading because it has nothing to do with how hot or cold the bulb is. The notion of temperature comes from the concept of “warm lighting” and “cool lighting” in photography. Warm lighting is yellowish and makes people feel more relaxed and comfy. Cool lighting is bluish and makes people more awake and alert. In fact, ample research has shown that the bluish light from computers and phones can cause insomnia.

Technically, the measurement of color between blue and yellow is measured in something called Kelvin (K). For the home, lightbulb colors often have friendlier labels, like these below:

• Soft White / Warm White (2700K – 3000K): Best for bedrooms and living rooms; providing a traditional warm, cozy feel to them
• Bright White / Cool White (3500K – 4100K): Best in kitchens, bathrooms or garages; giving rooms a whiter, more energetic feel
• Daylight (5000K – 6500K): Best in bathrooms, kitchens and basements; good for reading, intricate projects, or applying makeup – provides the greatest contrast among colors

If you’re still wondering why many people have switched to LED lightbulbs, including me, here’s a summary of why I switched to LEDs.