Tuesday, May 24, 2011

How bright is a light bulb? Lumens Vs. Watts

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This 5W LED from WholesaleLED.com has
400 lumens of light.
That's more than a 40 Watt Bulb
There seems to be some confusion about how to tell how bright a light bulb really is. It was easy enough when we all used incandescent lights. You could choose from a 40, 60, 75 or 100 watt bulb, and we all have a rough idea of how bright that will be.
When you begin to get into new lighting solutions like CFLs and LEDs, using the wattage doesn’t work very well any more. Now you have 20 watt CFLs, and 12 watt LEDs and no idea what's going to keep you from going blind while reading. Well, read on and learn how to tell how bright something actually is. Before you lose your eyesight. 

Just Look to the Lumens
To understand this, it's important to know the difference in lumens Vs watts. A Lumen is standard unit of light as it is perceived by the human eye. Essentially, it will tell you how bright something is, unlike a watt, which is actually a measurement of energy consumption or output. The lighting industry has standardized ways that it measures the total emission of light from a product and include it on most packaging. Here’s  the lumens from some everyday objects to give you a better idea.
  • 40 watt incandescent = 380 – 460 Lumens
  • 60 watt incandescent = 750 – 850 lumens
  • 75 watt incandescent = 1100 – 1300 lumens
  • 100 watt incandescent =  1700 – 1800 lumens
  • Direct sunlight = 100,000 lumens.

One of the reason LEDs are so attractive is that with a fraction of the power use (watts) you can get the same amount of light (lumens) as an incandescent.

You can get as many as 110 lumens per watt with an LED bulb. Compare that to an incandescent, which only produces 12-17 lumens per watt. Now that’s some science that can save you money. 
Check out some of our other articles if you want to learn more about how an LED light bulb works.

How much wattage do you like in your home? Did you use 60 or 75 watt lights?

-KS

42 comments:

  1. This is really helpful! Thanks!

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  2. This comment has been removed by a blog administrator.

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    1. "Shaun Marsh" is posting spam to up the google rating of his website.
      That's why he wrote something useless and included a link. I'd suggest you delete it.

      Delete
  3. The issue with the higher lumens output with compact fluorescents and LEDs is they can exceed what is best for the human eye and cause irreparable damage. In museums, to ensure perishable materials, such as basketry, do not get damaged, lumens should not exceed 400. There isn't a single compact fluorescent available to the consumer below 750 lumens and when placed in a bedside lamp...

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    1. guess you have been kept in the dark?

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    2. I would assume the 400 lumen limit in the museum is the measure of the light reaching the displayed items. This will be much lower than the source lighting. Depending on the type of lights used (probably high pressure sodium in a museum) the light may be uni-directional (like most LEDs) or omni-directional (like CFLs). Light strength also decreases with distance. Therefore the 750 lumens of a bedside CFL will not reach your eyes unless you use an extremely efficient reflector and stick it right in you're eyball. Personally, I would want to use a 20W "daylight" CFL about one metre away to read by. A 15W would have done when I was in my teens - except they didn't exist then. :-D

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    3. I have found the impossible, by searching the internet: 200 lumen compact flourescent. http://www.amazon.com/Sylvania-29160-Micro-Compact-Fluorescent/dp/B00365PA4M/ref=sr_1_5?s=lamps-light&ie=UTF8&qid=1397168724&sr=1-5&keywords=compact+fluorescent+bulb

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    4. The good news about LEDs is that you can use a dimmer!

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  4. Brilliant. That's just what I needed to know!

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  5. Very helpful. Written in a simple and easy to understand manner for the layperson.

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  6. Thanks for the help now I have an idea of what to look for.

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  7. Keep posting more news on LED lights and bulb. We are reading and listening to you fellas!!

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  8. thanks. now i know!

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  9. I feel this is one of the so much vital information for me. And i am happy studying your article. However should observation on some general issues, The web site taste is ideal, the articles is actually great : D. Excellent activity, cheers.

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  10. Thank you for give vastly nice info. Your web page is cool.I am impressed by the information that you have on this web page. It shows how well you understand this topic. Bookmarked this page, will come back for further.

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  11. Very helpfull information. Thanks

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  12. This article was exactly what I was looking for. Thank you!

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  13. Measured at what distance from the light source ?

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  14. I believe that 110 lumens per watt is a bit too optimistic. I know that's what manufactures say, but they measure the intensity and power consumption mostly in the few seconds of operation, just before the LED heats up.
    On a day to day bases it's more like 85-90 Lumen/Watt.

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  15. Exactly what I was looking for thanks!

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  16. Outstanding information, thanks.

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  17. lol to the idiot that says LEDs heat up. They are instant on like incandescents. CFLs are the only ones that take a little bit to warm up. LEDs are amazing technology that will only continue to flourish!

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    1. Some LED's are instant on and some have a delay.
      LED's do heat up. They have a heat-sink on them to dissipate the heat. Some are hotter than others and some get too hot and it causes them to fail prematurely. I agree the technology is improving.

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    2. Some LED's are instant on and some have a delay.
      LED's do heat up, but less than other lights. They have a heat-sink on them to dissipate the heat. Some are hotter than others and some get too hot and it causes them to fail prematurely. I agree the technology is improving.

      Delete
    3. Some LED's are instant on and some have a delay.
      LED's do heat up, but less than other lights. They have a heat-sink on them to dissipate the heat. Some are hotter than others and some get too hot and it causes them to fail prematurely. I agree the technology is improving.

      Delete
    4. Some LED's are instant on and some have a delay.
      LED's do heat up, but less than other lights. They have a heat-sink on them to dissipate the heat. Some are hotter than others and some get too hot and it causes them to fail prematurely. I agree the technology is improving.

      Delete
    5. False information.

      Delete
  18. If a light is 170 lumens is it bright enough to read by?

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    1. Thanks for your question. You would probably want something with at least 800 lumens to read buy. That would be closer to a 60 watt equivalent bulb. Much better for the eyes.

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  19. i wanna know please if it's wise to use a light bulb with:
    75 lumens.
    17 LED
    6 K color.
    120 beam angle

    thanks

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  20. Some LED's are instant on and some have a delay.
    LED's do heat up, but less than other lights. They have a heat-sink on them to dissipate the heat. Some are hotter than others and some get too hot and it causes them to fail prematurely. I agree the technology is improving.

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  21. What would be powerfull enough to light a small area of a football field for training with regards to lumens?

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    1. Great question! You would be looking for something with tens of thousands of lumens to light up field. Several lamps with 5,000 plus lumens would probably do the trick. In an LED, that would mean flood lights at around 500 watts each.

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  22. What would be the brightest (and I mean almost blinding) hand-held light I could get? I would like to be able to turn it on and shine it into the alley (so I'm talking about a BEAM of light) to scare the bejeebers out of a couple of kids that are stealing things out of people's sheds in my neighborhood around 3 a.m.

    Thank you!

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    1. I have a cree led torch rated at about 2 watts but it is incredibly bright and a very long beam. you can get them on ebay.

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  23. how about a roman candle

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  24. Since most people are replacing an A19 bulb (in their homes anyway), it's probably useful to point out that a 7 watt LED is probably better as a 40-watt replacement and a 10 or 11-watt LED is probably best for replacing a 60-watt. Just thought the PAR30 reference (if a reader knows what that is) might confuse them if they're trying to replace a traditional A19.

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  25. Thanks for the plain language explanation.

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  26. I am pro LED and have many in my home. However the suppliers continue to vastly overrate LED lights. A 7 watt LED could be used as a 40-watt replacement but it is not going to give you the same amount of light (lumens). A 7-watt LED will only give the equivalent of a 28-watt incandescent bulb.
    My latest ones are "equivalent to a 50-watt bulb", 561 lumens, efficiency at 49 lumens/watt, energy used 11.3-watts. Sounds great, doesn't it? However 561 lumens is less than a 40-watt incandescent bulb and the INPUT to the LED fixture is 120VAC at 200ma = 24-watts NOT the stated 11.3 watts.

    A 50-watt incandescent should give 750 lumens, though few do. LED packaging claim 400+ lumens to 600+ lumens are ALL 50-watt replacements. How can that be?

    So, be informed, look at the real data - not the wild claims.

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  28. Im looking at buying a handheld spotlight two to choose from both 9" hid lights one is 100w with around 3500lm the other is 55w with 5500lm witch one is going to give off a better light more lumens or watts

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