LED, Lumens, Kelvin…WATT are you talking about?

Just when I mastered CFLs and accepted the phaseout of T12 fluorescents, 100W and 75W bulbs, enter the LED bulb. Anyone who has tried to shop for these bulbs is probably as frustrated as I am when trying to find a 100W “equivalent” bulb. These bulbs don’t yet exist on store shelves and the word “equivalent” is a useless gauge to determine similar light outputs of incandescent, CFL and LED.  I have yet to find any equivalent equivalents.  Yes, you read that correctly.

Simply trying to find a suitable 100W “equivalent” LED table lamp replacement has become an infuriating chore.  Most stores don’t yet carry a wide variety of options to suit what I believe to be standard lighting for everyday use.  It’s a hodge podge of shapes, styles, output, color temperature and energy used that I’m sure will change as the technology matures and more options are brought to market.

First some terminology:

  • A Watt is the amount of power consumed by a bulb per hour
  • Lumens are a raw measure of light output
  • Kelvin is color temperature – 2,700K (indoor soft white) to 5,600K is bright white like a fluorescent.

To replace the 100W table lamp bulb with an LED equivalent, I settled for a funky Philips 17-Watt (75W equivalent) LED Soft White (pictured above).  It does produce a nice light, albeit less Lumens than I desired.

For my kitchen, I searched for an 85W equivalent LED recessed downlight, but the stores don’t yet carry it either. I settled for lower output 65W LED “equivalent” lights (Ecosmart 10.5W / 2,700K / 575 Lumens LED).  The packaging claims it replaces 65W bulbs so I thought the room would be dimmer, but my room is actually brighter than the 85W CFL bulbs they replaced! Arghh! The product is a pretty neat one-piece replacement can with integrated trim that’s easy to install.

Watts used to give us a good idea of how much light a light bulb would produce. But as bulbs now produce more light (or lumens), Watts have stopped being a useful guide to brightness.  As LED bulbs continue to improve in efficiency, you can find two 65W equivalents that can give quite different levels of light output, perhaps as much as a third more or less. It’s not to exaggerate power (consumption), but older and less efficient LEDs could use older and less efficient electronic driver circuits. Big box stores have a chart that does a fairly good job of explaining the differences between Lumens, Kelvin across incandescent, CFL and LED. If only the product were consistent with the claims.

Be careful to check color temperature as that varies from bulb to bulb too.  The four 65W equivalent Ecosmart downlights (575 Lumens) I replaced were listed as soft white (2,700K). Three of the lights were soft white while the fourth was noticeably whiter at about 3,000K.

So how easy is it to replace a 85W flood?  Bring Tylenol or Acetaminophen equivalent.

– Watts are no longer useful as an indication of the brightness.
– Lumens have taken over to measure the brightness of a light.
– Color temperature (Kelvin) describes incremental color, from Soft White to Bright White.
– LED’s are more energy efficient than CFLs. A 19W CFL (75W) could be similar to a 10.5W LED or half the energy used.

10 Comments on LED, Lumens, Kelvin…WATT are you talking about?

  1. I want to affirm the comments that even at 2700 Kelvins, LED lights still don’t emit what I’d describe a “soft” or “warm” light. I experimented, replacing a 60W-equivalent CFL at 2700K with a 60W-equivalent LED, also rated at 2700K. The difference was obvious. The CFL produced a warm, yellowish light (which is exactly what I want), while the LED produced a whiter, colder light. Same Kelvin number, different quality of light. At this rate, I’ll have to replace my CFLs with other CFLs–even though they burn more electricity–until this issue can be acknowledged and resolved. This is the only place, BTW, where I see this issue being discussed!

  2. I too am having a very difficult time finding an LED bulb that is still “warm”. Although they call out the equal amount watts and state the kelvin is equal to a warm light, they aren’t. I’ll be happy when the LED bulb Gives off anything but that “white, cool” light. While you can find a fluorescent that is warm, they aren’t dimmable. Frustrating!!!

  3. Richard, yes, We’re all over the LEDs. but also recognize that other technologies such as magnetic induction fluorescent and metal halide are (currently) more appropriate for some applications. But they are interim technologies and I believe will be replaced entirely by LED in 10 to 20 years. For a glimpse into the future of LED technology, Google ‘Haitz’ Law’.

    And to answer your question, customers are pretty savvy when provided the facts. They quickly understand that longevity is all about heat management. Screwing a replacement LED “bulb” into a traditional lighting can will create a nice little oven that will guarantee disappointment in your LED investment. A leapfrog technology such as LED requires re-educating the consumer to think about a new type of lighting fixture, and less about a new type of bulb.

    For more on the basics of energy efficient lighting, check out a recent blog article we published: http://lumenistics.com/energy-efficient-lighting-basics/

  4. Pete Marotta // May 6, 2012 at 11:32 am // Reply

    Great article- I have converted two of my stores to 100% LEDS, one was a store with 8 foot T-12 lamps. my LED vendor created 8 foot LEDS for me with internal drivers that fit right into the existing fixtures. The results have been spectacular. Sales have increased, the store looks brighter and the CEO says it looks like a brand new store! The power saving have calculated to be $2000 a month. My local utility would not give me ANY incentives, but the power saving and reduced maintenance allowed for an ROI for 3.2 years. I recommend anyone with 8 foot T-12 to contact my vendor and try them out…

  5. I do think the average consumer recognizes that change is inevitable and the reduced power consumption is the primary inducer. For me, having a television production background helps in that I understand how intensity, color, mixing ambient and studio lighting affects the mood of the space. The average consumer probably wouldn’t notice the difference if they accidentally install several bulbs in the same room ranging from 2,700K-3,000K bulbs. In fact, a close family member replaced several warm CFLs with bright-white LEDs and didn’t think twice that their living room now looked like a bright mail room. When I pointed it out, they did replace the bright white LEDs with the softer Ecosmart downlights.

    So are people just accepting because they are enticed by energy savings even though there are limited choices available? I think the interior designers might be cringing right about now. Are store employees not well trained to really explain the differences? Is the packaging confusing because it does not do a good job of explaining the product’s use and application? Or am I just too critical?

    Bob, quick question. I have a RAB 125W Metal Halide Wallpack. As expected, the ballast hums and the vibration telegraphs through the wall. How does the LED react?

  6. Bob White // May 3, 2012 at 8:21 am // Reply


    A further consideration is that LEDs (emitters, not lamps) are directional while fluorescent tubes, CFLs and incandescent lamps emit light in many directions. Since a lumin is the total amount of light given off by a light source (measured as the amount of light falling on the inside of a 1′ sphere with the light source at its center), you can’t accurately use lumins to compare LEDs with other downlight or floodlight sources. Using lumins works fine for comparing the type of lamp pictured in your article because it is designed to emit in all directions (using multiple emitters and/or reflective surfaces), but downlighting is a different story. A “normal” lamp in a downlight fixture relies heavily on a reflector to make the output directional, otherwise more than 1/2 the lumins produced would be wasted. An LED on the other hand is already directional so all the lumins produced are going in the desired direction to start with. So for directional lighting you can’t use the source lumin output for comparison, you have to use the directional/fixture output. That is how a 26W LED wallpack producing 1800 lumins can replace an HID wallpack using a metal halide lamp putting out 3700 lumins with the same amount of light reaching the lighted area. Good luck finding that info on the box or at a big box store.

  7. Richard, I think you have done a good job of portraying a confused consumer, which do exist, but I do not think the average consumer (residential or commercial) is however having that much difficulty. They get watts, kelvin, warm white, cool white, and equivalent to. What they really get.. is 5 watts verses 60 watts or 30 watts verses 290 watts.. Instant on, verses a light that needs to warm up. A safe environmentally responsible light “LED” verses CFL’s that are not environmentally friendly (actually hazardous to your health, check out what you should do if your child knocks over a lamp in your home and one breaks)…. and they also understand CFL’s do not last as long as they say… My recommendation is to look for a replacement for what you currently have. With that information either from the bulb itself or the box of the back-up light, go purchase 1 LED Light bulb, as close to that standard as you can. The worst case is the light doesn’t perform as required, so you unscrew it and move it to a location which doesn’t need as much light output, say a closet, or the light you leave on when you are out, then try again with your new found knowledge. For the most part that one light if you used it 4 hours a day will last you 20 plus years., and save you a lot of energy, and your hard earned dollars.
    We are living in changing times… time to change.

  8. Richard, Interesting article. LED lighting is truly a shift both economic and technological a major disruptive technology in a $250 billion/year industry (from McKinsey report on lighting). My (lighting) company has recognized that there is no shortage of exciting new technology, but certainly there is a shortage of qualified and objective explanation of decision factors to consumers and business buyers alike.

    • Thanks for the feedback Simon. I recently met with a vendor who began manufacturing 2×2 LED ceiling panels where they claim the light will last over 20 something years. That would eclipse the term of most tenant leases by double. When I pressed them on longevity, they admitted the driver would last less than half the life of the LEDs, so there would be a cost associated with replacing the driver. These are all confusing factors for the end user.

      How have you explained the longevity issue to your clients and what’s been the economic reaction of architects, landlords and GC’s? Are you actively promoting the use of LEDs?

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