Sunday, October 23, 2011

Lighting Efficiency Summary, 2011

This list is taken directly from a Martin Holladay article at GBA:

Here are some relative lamp efficiencies:
  • "Indancescent bulbs produce about 14 to 17 lumens per watt.
  • Low-cost LEDs produce about 15 to 25 lumens per watt.
  • High-quality LEDs produce about 40 to 70 lumens per watt.
  • CFLs produce about 48 to 60 lumens per watt.
  • T-5 and T-8 linear fluorescent tubes produce about 98 to 105 lumens per watt."

And I just found this increased efficiency LED bulb that kicks out 94.4 lumens/watt:

Even though in the article Martin states:
  • "For now, screw-based CFLs are the best bulb choice for residential lighting.", I think LEDs have just reached the tipping point. 


  1. I just read a not so flattering review of this bulb from James Bedell.

    He's a lighting designer, so he's a bit more picky than most about lighting, but I think I'll hold off on LEDs for a bit longer.

  2. Oops, nevermind. Looks like this is a different brand. Sorry!

  3. It's not dimmable, which is a big issue, but...

  4. 1. CFLs have a disposal problem--in theory.
    2. A huge amount of R&D money is flowing into LEDs so you can expect improvements.
    3. Just focusing on lumens/watt is too narrow. Lifetime is also important--especially if it takes a lot of labor to replace a burned-out lamp. Usage is also important. For example, I have a 100-watt incandescent light in my attic. Total annual run time is less than 1 hour per year. Why should I even think about alternatives?

  5. Hi Dave, thanks for weighing in. I see a lot of your posts about Denver-centric issues, and I appreciate your concerns.

    I definitely should have mentioned the bulb lifetime issue. LEDs win this category hands-down, with "expected lifetimes" of 20,000 - 40,000 hours. The bulb I called out above doesn't even have a rating. The manufacturer just says: "G7 Power guarantees this bulb will not burn out under normal operating conditions. If it does, we will replace it."

    This lifetime approaches light bulb nirvana: it means if you buy a new home with these bulbs installed, you will never need to change a bulb in your lifetime.

    You might, though, just to save even more on operating cost in the future. These bulbs have an expensive aluminum heat sink, which means they must dissipate significant heat. That means there is still room for lighting efficiency improvements.