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Page history last edited by Soren 11 years, 4 months ago Saved with comment



The Navy has some background data from 2002 (also linked from Data) that shows Low Pressure Sodium generating well over 100 lumens / watt (183 for the biggest lamps). Lumens is the standard measure of the amount of light emitted from a bulb. Watts are what we pay for and incandescent lights consume a lot of watts (e.g. 100W) to make not so many lumens (e.g. 1700 or 17 lumens/watt). More lumens / watt is better and below are some better-than-incandescent options.


Would you carry and trade CFLs on your next trip?

What are the "induction lamps" mentioned that Cupertino is installing?


Lighting characteristics

There are typically four things people care about with lights, especially when it comes to incandescent alternatives.  Progress is being made on all fronts for both CFLs and LEDs, but it's important to be on the lookout for the mythical "dimming, soft-white, mini, instant-on" bulb (i.e. behave exactly like an incandescent :).

  • warm-up time: older CFLs could take up to a minute to come to full brightness and CFLs that live outdoors in the cold will take longer to come on than warm bulbs.
  • size: if you can't fit a bulb into your fixture or if it looks ugly in your fixture, you're going to resent an incandescent alternative.
  • color temperature: lots of progress is being made in this area, but if you get blue light where you wanted yellow or three bulbs from the same package aren't exactly the same color, you get unhappy users
  • dimming: many lights are on dimmer switches and normal CFLs don't dim.  Some folks also claim the dimming bulbs don't last as long (even if not dimmed?).


CFLs (~75 lumens/watt)

Sources & Advice



  • EPA fact sheet
  • many lighting and hardware stores, such as IKEA and Home Depot, accept fluorescent bulbs for safe disposal
  • lamprecyle.org has a state-by-state recycling contacts map





Must [...] Identify the light color. (Qualified bulbs are available in designated correlated color temperatures (CCT): 2700K (warm white), 3000K (soft white), 3500K (white), 4100K (cool white), 5000K (natural), or 6500K (daylight). Provide a color rendering index (CRI) of 80 or more. Incandescent light bulbs have a CRI close to 100. (Learn about color rendering index and correlated color temperature.)


  • thebulb.com's about page includes an explanation of color temperature:



Color Temperature

The color temperature of a light bulb can best be described as how the light compares to “natural” sunlight. Outdoor sunlight has a color temperature of around 5,500K. Bulbs with a higher color temperature (closer to 5,000K) will produce light that is more “cool” or blue. Bulbs with a lower color temperature will produce light that is more “warm” or yellow. The color temperature of a light bulb is usually described by how “white” a bulb is, like soft white, bright white, etc.

Description Color Temperature
“Warm white” or “Soft white” < 2700 K
“White”, “Bright White”, or “Medium White” 2900 - 3000 K
“Cool white” 4000 K
“Daylight” > 5000 K

Source: http://www.thebulb.com/store/t-compact-fluorescent-light-bulbs.aspx


LEDs (~55 lumens/watt?)



"The GS6 LED downlight has a system efficacy of up to 35 lumens per watt, which is comparable(??) to compact fluorescent downlights, and more than three times the efficacy of a bare 65W incandescent reflector lamp." This story indicates that portablelight.org's solar-powered LED lamp gets 80 lumens/watt. Take that, GS6.






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