# On The Matter Of Watts Vs. Lumens, We Find That Lumens Win

Imagine a future where we buy light bulbs based on how much light we want, instead of how much energy they burn because all light bulbs are already pretty efficient. Oh wait, that’s now!

### 15 Responses to On The Matter Of Watts Vs. Lumens, We Find That Lumens Win

1. Bob says:

Don’t forget to factor frequency and associated problems into the equation.

2. fj says:

LED lighting is totally positively disruptive despite its expense.

3. Henry says:

Sorry if this is off topic. I thought Joe should know and I don’t have his email.
Apparently, the password has been released for the remaining UAE emails (however many thousands of them) and it’s already been dubbed “Climategate 3.0″
H.

4. Strange, I buy lighting sources based on two values not even mentioned. As my wife is an artist, often working at night, she need light that approximates the color values of daylight. Then, we also purchase low wattage (25-40) incandescent bulbs because they also produce heat that keeps our baby chickens warm while they can see to eat whenever they are hungry. Admittedly, the 2nd reason is not so important, but having the right light is important for any work of art. LED lighting at 6500 kelvin is not cheap. Nor are 6500 kelvin CFL’s which run around \$18 for 26 w. at Walmart.

• fj says:

I am a little rusty on the exact numbers — and possibly units — but incandescent light is something like 3200 degrees kelvin and considered much “warmer” (redder) in color temperature than sunlight rated at something like 6500 degrees kelvin which is considered much “colder” (or bluer than incandescent).

• fj says:

Wesley, apologies for misunderstanding your comment . . .

• Dennis Tomlinson says:

A paragraph on color temperature: As the temperature of a blackbody radiator is raised above absolute zero it begins to emit energy in the deep (very long wavelength) infra-red. The hotter the blackbody is, the shorter the emitted wavelength (Energy increases as emitted wavelength decreases). As the blackbody temperature is heated toward 1000K the emission wavelength crosses from the near infra-red into the deep visible red at a wavelength of about 610nm. A curve of blackbody temperature is typically superimposed onto the CIE Chromaticity diagram, which is worth a Google. Continuing to crank up the heat, as the radiator approaches 2800K the emitted color is a yellowish-white (soft white), which mimics the emission from a tungsten bulb. Natural sunlight is about 5800K, while 6500K is a blueish-white.

Sorry, a second paragraph: LED’s create white light in two ways: 1) packaging a red, green, and blue LED together (tri-chromatic). And 2) By coating a blue LED with yellow phosphor (bi-chromatic). The Blue LED emits in the 650nm range, which pumps the yellow phosphor causing it to glow in the longer wavelength, red-green portion of the spectrum. Along with the blue which leaks through the phosphor, this mixture is perceived by the eye to be white light. [The eye's color receptors (cones) come in three flavors - red receptors, green receptors, and blue receptors.] The color temperature of a white LED is controlled by increasing or decreasing the amount of red phosphor in the mix.

• Dennis Tomlinson says:

Correction: A blue LED emits at around 450nm – not 650nm.

-5 points

5. “Disruptive” meaning?

• Ric Merritt says:

A term from the peppier precincts of business, referring to something so new and shiny it will turn those old, drab predecessors into buggy whips.

• fj says:

nice.

6. Will Fox says:

Please fix the typo in the opening sentence.

7. James Adcock says:

The true “cost” of a lightbulb — and trust me on this given that I am our family’s designated “tall person” is not the cost of 20 cents it takes to buy a throw-away incandescent but rather the time and effort to drive to the big box retailer, choose and buy the bulb, drive back home, get out the ladder, turn off the power, climb up the ladder, unscrew the dead light bulb — which has now magically glued itself to the socket, okay get out the pipe wrench to remove the old light bulb, screw in the new one hopefully without dropping it, climb back down the ladder without hopefully dropping *yourself* and then dispose of the bulb “properly.” Repeat about once a month. With CFL’s the same story, except the light quality sucks, and then the bulb grows dim before it dies. And then after replacing the CFL drive the old one down to the local hazmat facility for proper recycling of the enclosed mercury. Whereas with LED’s I do this ONCE and then after I die my children can unscrew the LED’s and move them to their own households! And until I die I keep saving time and money year after year after year. Explain to me again, why do people buy a \$200 light fixture, pay \$200 to have an electrician to have the light fixtue installed — and then install a gyppo \$0.20 light bulb??? LEDs make my life SO MUCH BETTER!

• John Hollenberg says:

While I agree LED bulbs are significantly better than CFL, if you buy a dozen CFL bulbs and save the old ones until you have a dozen to recycle, you have very little driving to make these bulb changes. No need to overstate your case.

8. Tom says:

We are still waiting for 60 watt equivalent (roughly 600-800 lumens) small base, candelabra style LEDs.

I’ve been replacing bulbs with LEDs for about 2 years. They are indeed a huge improvement over both CFLs and incandescents. I can’t wait for more of my bulbs to die (CFLs last too long…). On the other hand -at \$35 each – I can wait.