Useful Information on the New Light Bulbs (CFL, LED)

Problem: you are holding one of the newer CFL or LED light bulbs in you hand; you don't have the original box; all you have is the bare bulb. So how do you tell:

What is the "Equivalent Wattage"? Is this a "60 watt", a "75 watt", or a "100 watt" bulb?

What is the "Color Temperature"? Is this a "warm white", a "cool white", or a "daylight" bulb?

In the age of incandescent bulbs, a "100 watt" bulb drew 100 watts of power. The bulb itself said "100 watts". But with the newer lighting the bulbs dissipate much less power. So, for example a "100 watt" CFL bulb will show 23 watts on the bulb, and a "100 watt" LED might show 15 watts on the bulb. And this wattage may vary depending on the manufacturer.
 So how does one tell how bright the thing will be? Well, here's a little tutorial that will describe how you can determine this. In addition, it'll describe how to determine if it is a "warm white", "cool white", or "daylight" device, since that information is also missing on the bulb itself.

When you buy a CFL or LED light, the box lists the "Equivalent Wattage". This is the wattage the bulb would be if it were an incandescent bulb. So you knew how bright the device would be.
 Further, the box displayed "warm white", "cool white", or "daylight"

But when you have the bare bulb, you get "light stats" - all the technical info. But since your magic decoder ring's in the shop, you don't have a clue about how bright it will be, nor its characteristic color.

light box light bulb

No problem. Jimmie's Light Tutorial will explain all this.

The brightness is shown as Lumens.

The color is shown as Degrees Kelvin.

The Brightness

Since the wattage of light bulbs is all over the place, manufacturers now express a light bulb's brightness directly. The unit is "lumens". To compare lumens to the former watts, simply remember three numbers: 800, 1200, and 1600!

800 lumens equals 60 watts

1200 lumens equals 75 watts

1600 lumens equals 100 watts

Note that these numbers are approximate, but it's easier to remember these numbers than it is to remember the variations you will see on different bulbs. For example, "75 watt" equivalent bulbs may range from 1180 to 1210, and "100 watt" equivalents may range from 1570 to 1680.

The Color

The color (or "Color Temperature") of light bulbs is still referred to as "warm white", "cool white" and "daylight", but will be shown on the bulb itself as "Degrees Kelvin". So you will see, for instance, "2700K" on a warm white light, and "5000K" on a "daylight" light.
 Note that is not "Temperature" as such. If it were temperature, as in heat, 5000 degrees would clearly be "hotter" than 2700 degrees. It's "Light Temperature", which varies from reddish/orange to white/blue. Greens and purples are left out. Consider heating a piece of metal. It will first flow red, then orange, then white. So 5000 degrees in "Light Temperature" is "cooler" than 2700 degrees in "Light Temperature", even though the metal is "hotter" when it's white.
 So the numbers to remember are:

2700K - 3000K is warm white (or "soft white")

3500K - 4000K is cool white

5000K is daylight

Warm White. These bulbs were 2700K

Cool White. These bulbs were 3500K. Note that some manufacturers refer to 3500K as "Neutral" and 4000K as "Cool White"

Daylight. These bulbs were 5000K. When you really want to light stuff up, use "Daylight".

warm white cool white daylight

A final note:
 The lights you use can dramatically change the color of paint! The room shown above actually has grey walls, and the frame around the picture is grey driftwood. So you can make greys look like tans simply by changing the light bulbs to "warm white".

Copyright © 2018 J.A.