100 Watt Bulb. Lumens?


A Lumen Reference Point

“100 Watt Bulb Lumens” was one of the first things I searched for when I started looking into alternatives for incandescent lighting.  Like you, I was looking for a reference point to compare options.  I, like most people, have a very good idea of the relative brightness of a 40w, 75w, 100w or 150w incandescent bulbs in my home and I know that 100w is the one I’m most comfortable with using for a lamp.  It’s the one that is going to be bright enough, but not too bright, for most situations.  Since wattages are no longer a good basis for understanding a light bulb’s brightness across different bulb technologies, I figured that lumen figure would be the starting point for my search.   However, there was a problem.  When I searched, the answer to the question of “How many lumens does a 100 watt bulb put out?” was not the same from source to source.  Some places said over 1700 lumens, others 1245, and others 1100.   And some 75 watt bulbs claimed to put out 1150!   What is going on here?


Different 100W Bulbs Have Different Lumen Ratings

Design differences.   For example, some bulbs can be optimized for light output at the expense of operating life.  The GE 41034 (link) is a perfectly simple bulb and outputs the conventional upward limit of 1710 lumens.  750 hours is the rated lifespan for this bulb, which is not very long as bulbs go these days, and there’s an Amazon review about it with a complaint of it lasting only 4 months for a user that usually has bulbs last for years.  This is just anecdotal but there’s nothing tough about the design of the GE41034 and that’s why it gets away with such a high lumen rating.  The more complicated the filament setup is, the more heat escapes from the bulb and the less light can be made at a given wattage.  The GE41034 is as simple as it gets, and therefore about as bright as it gets.  At the other end of the spectrum is the GE43209 Survivor Rough Service Bulb (link).  It’s got elaborate filament supports to make sure the bulb operates smoothly no matter what.  It’s designed to be used in in high vibration environments any orientation (aka Universal Burning Position).  Its lumen rating is a paltry 1190 but its lifespan is an impressive 3000 hours!  That’s 4 times as long!  Another factor that can reduce the lumen rating of a bulb is 3-way switchability.  It’s often convenient, but the caveat is that there are multiple filaments used inside the 3 way bulb and again, more complication means less efficient light production; 1500 lumens in this case.


Lumen Ratings Firsthand

Given that 100watts can mean so many different levels of brightness, it’s best to use a first hand reference.  In order to make apples to apples comparisons between incandescents and rival bulb technologies you’re researching, it’s best to look at a bulb you already have and find out its lumen rating using Google (the newer the bulb the more reliable it will be for producing its rated output). The manufacturers usually have detailed online catalogs that will show up when you search, so you should be able to zero in on yours pretty quickly.   Also look for a color temperature rating for your bulb if possible, because that will really help narrow things down when you’re presented with all the color temperature and CRI jargon.

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