# LED lightbulbs output equivalency **URL:** \ **Category:** Factual Questions\ **Created:** [September 22, 2011, 5:48pm UTC](https://boards.straightdope.com/t/led-lightbulbs-output-equivalency/597218 "2011-09-22T17:48:04Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Terr](https://avatars.discourse-cdn.com/v4/letter/t/839c29/32.png) [@Terr](https://boards.straightdope.com/u/Terr)\ **Post date:** [September 22, 2011, 5:48pm UTC](https://boards.straightdope.com/t/led-lightbulbs-output-equivalency/597218/1 "2011-09-22T17:48:04Z")
I was looking around for 100W-equivalent LED bulbs. Found a few. Example: > **[LED Dimmable 100-120W Replacement Bulb. Extreme Brightness Color: Warm White -...](https://www.amazon.com/Dimmable-100-120W-Replacement-Extreme-Brightness/dp/B002SL4QVI)** > > LED Dimmable 100-120W Replacement Bulb. Extreme Brightness Color: Warm White - Led Household Light Bulbs - Amazon.com [http://www.amazon.com/Maxxima-BR40-LED-Light-Bulb/dp/B002FX6Z9A/ref=sr\_1\_2?s=hi&ie=UTF8&qid=1316713408&sr=1-2](http://www.amazon.com/Maxxima-BR40-LED-Light-Bulb/dp/B002FX6Z9A/ref=sr_1_2?s=hi&ie=UTF8&qid=1316713408&sr=1-2) A couple of questions, though: 1. The 100W incandescent bulb’s output is around 1700 lumens. The above bulbs, one of them is 920 lumens, the other is 1030 lumens (580 if it is “warm white”). Seems like they are a lot dimmer than the 100W incandescent ones. How exactly are they “100W equivalent”? 2. It seems like the manufacturers are struggling to pack that many LEDs into a bulb-size area. So - why make it a “bulb”? Why not make it in another shape? A flat thick 1-sq-ft panel for example. A “tile bulb”? Then the output would only be constrained by the area. Hell, make it 10 sq ft and 3000 lumens output, all for 30W power consumption. THEN it will be worth $30 or so. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 22, 2011, 5:59pm UTC](https://boards.straightdope.com/t/led-lightbulbs-output-equivalency/597218/2 "2011-09-22T17:59:52Z")
I agree that saying that 920 = 1700 is pretty questionable. They may be taking into account the LEDs’ directional light output. So, depending on the fixture, the LED “bulb” may actually deliver as much useful light. As far as form factor, I think you will start to see many more LED-specific light fixtures, that take into account the point-source nature of LED emitters. However, the market right now is on incandescent replacements, which necessitate the “bulb” form factor. ---
**Author:** ![TroutMan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/troutman/32/6721_2.png) [@TroutMan](https://boards.straightdope.com/u/TroutMan)\ **Post date:** [September 22, 2011, 7:57pm UTC](https://boards.straightdope.com/t/led-lightbulbs-output-equivalency/597218/3 "2011-09-22T19:57:55Z")
> [@beowulff](#): > > I agree that saying that 920 = 1700 is pretty questionable. They may be taking into account the LEDs’ directional light output. So, depending on the fixture, the LED “bulb” may actually deliver as much useful light. This. [Here’s](http://www.lightbulb.co.uk/led-tubes-effective-lumens-measurement.html) one manufacturer that claims the effective lumens of their tubes is 46% higher than the actual because of the directional nature of the light. ---
**Author:** ![Terr](https://avatars.discourse-cdn.com/v4/letter/t/839c29/32.png) [@Terr](https://boards.straightdope.com/u/Terr)\ **Post date:** [September 22, 2011, 8:00pm UTC](https://boards.straightdope.com/t/led-lightbulbs-output-equivalency/597218/4 "2011-09-22T20:00:59Z")
> [@TroutMan](#): > > This. [Here’s](http://www.lightbulb.co.uk/led-tubes-effective-lumens-measurement.html) one manufacturer that claims the effective lumens of their tubes is 46% higher than the actual because of the directional nature of the light. “A fluorescent tube emits light in all directions. LED Tubes light is directional, meaning light goes where you want it.” Hm. With general lighting (which is what 100W bulbs are for), I usually want the light to be emitted “in all directions”. ---
**Author:** ![Kent\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kent_clark/32/105_2.png) [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)\ **Post date:** [September 22, 2011, 8:44pm UTC](https://boards.straightdope.com/t/led-lightbulbs-output-equivalency/597218/5 "2011-09-22T20:44:04Z")
> [@Terr](#): > > 1. It seems like the manufacturers are struggling to pack that many LEDs into a bulb-size area. So - why make it a “bulb”? Why not make it in another shape? A flat thick 1-sq-ft panel for example. A “tile bulb”? Then the output would only be constrained by the area. Hell, make it 10 sq ft and 3000 lumens output, all for 30W power consumption. THEN it will be worth $30 or so. And make every lamp and lighting fixture ever made obsolete? ---
**Author:** ![Baracus](https://avatars.discourse-cdn.com/v4/letter/b/2bfe46/32.png) [@Baracus](https://boards.straightdope.com/u/Baracus)\ **Post date:** [September 22, 2011, 9:10pm UTC](https://boards.straightdope.com/t/led-lightbulbs-output-equivalency/597218/6 "2011-09-22T21:10:49Z")
> [@Terr](#): > > “A fluorescent tube emits light in all directions. LED Tubes light is directional, meaning light goes where you want it.” > > Hm. With general lighting (which is what 100W bulbs are for), I usually want the light to be emitted “in all directions”. I think the problem is that those types of bulbs (PAR38 and BR40) are meant to be replacements for flood/spotlights. You can get LED bulbs that come in a “in all directions” form factor (A19) but I don’t think I have seen them over 60Ws. Many of the 60W bulbs, too, seem to have questionable output, although it seems that Sylvania does make one that puts out 810 lumen using 12 watts. ---
**Author:** ![Ann\_Hedonia](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ann_hedonia/32/319_2.png) [@Ann\_Hedonia](https://boards.straightdope.com/u/Ann_Hedonia)\ **Post date:** [September 23, 2011, 3:13pm UTC](https://boards.straightdope.com/t/led-lightbulbs-output-equivalency/597218/7 "2011-09-23T15:13:32Z")
> [@Terr](#): > > I was looking around for 100W-equivalent LED bulbs. Found a few. Example: > > [LED Dimmable 100-120W Replacement Bulb. Extreme Brightness Color: Warm White - Led Household Light Bulbs - Amazon.com](http://www.amazon.com/Dimmable-100-120W-Replacement-Extreme-Brightness/dp/B002SL4QVI/ref=sr_1_18?ie=UTF8&qid=1316713183&sr=8-18) > > [http://www.amazon.com/Maxxima-BR40-LED-Light-Bulb/dp/B002FX6Z9A/ref=sr\_1\_2?s=hi&ie=UTF8&qid=1316713408&sr=1-2](http://www.amazon.com/Maxxima-BR40-LED-Light-Bulb/dp/B002FX6Z9A/ref=sr_1_2?s=hi&ie=UTF8&qid=1316713408&sr=1-2) > > A couple of questions, though: > > 1. The 100W incandescent bulb’s output is around 1700 lumens. The above bulbs, one of them is 920 lumens, the other is 1030 lumens (580 if it is “warm white”). Seems like they are a lot dimmer than the 100W incandescent ones. How exactly are they “100W equivalent”? > > 2. It seems like the manufacturers are struggling to pack that many LEDs into a bulb-size area. So - why make it a “bulb”? Why not make it in another shape? A flat thick 1-sq-ft panel for example. A “tile bulb”? Then the output would only be constrained by the area. Hell, make it 10 sq ft and 3000 lumens output, all for 30W power consumption. THEN it will be worth $30 or so. There are hundreds of different size and shapes of LED lighting out there (including panels, which is what you are calling “tiles”)…it’s just that most of them aren’t geared to the residental consumer market…and most of them cost WAY WAY WAY more than thirty bucks. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [September 23, 2011, 4:13pm UTC](https://boards.straightdope.com/t/led-lightbulbs-output-equivalency/597218/8 "2011-09-23T16:13:14Z")
I don’t know… I saw some LED floodlight bulbs at Home Depot the other month; it seemed to me the whole cone of the “bulb” was heat sink fins. I wonder how practical that sort of device is. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 23, 2011, 4:22pm UTC](https://boards.straightdope.com/t/led-lightbulbs-output-equivalency/597218/9 "2011-09-23T16:22:04Z")
> [@md2000](#): > > I don’t know… I saw some LED floodlight bulbs at Home Depot the other month; it seemed to me the whole cone of the “bulb” was heat sink fins. I wonder how practical that sort of device is. “Practical?” For what? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 23, 2011, 5:48pm UTC](https://boards.straightdope.com/t/led-lightbulbs-output-equivalency/597218/10 "2011-09-23T17:48:10Z")
If you have a standard bulb, and you want the light only in one direction, you put it in a mirrored housing. Most of the lumens still end up being useful, no matter what direction the bulb emits them in.