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I plan to replace a CFL lighting fixture in a small room (10' x 15'), due to its being too dim and giving less-than-perfect light.

I'd like to install something that would give me 3500K light with color rendering index (CRI) ≥ 85.

My options are seemingly halogen and LED. I'm OK with replacing the fixture, adding transformers, etc.

  • Halogen bulbs I encounter seem to have low power efficiency, below 20 lm/W (example). This means lots of heat, which I would rather avoid.
  • LED bulbs I encounter usually have CRI of 80 or worse (example), which I would rather improve on.

What am I missing?

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It seems to me, you might be missing a question? Are you trying to find a bulb with specific characteristics, or trying to find out why manufacturers don't make a bulb that meet you specific needs? – Tester101 Dec 17 '12 at 13:14
@Tester101: yes, my question is a bit vague. I suspected that I may be misunderstanding the area, and someone will tel me: "Look, these [classes of] lamps is an obvious example of what you must be using". Efficient halogen lamps, small-scale HID lamps, etc. Now I'm going to accept the most upvoted answer and ask about specific lamps separately. – 9000 Dec 18 '12 at 3:19

2 Answers

up vote 1 down vote accepted

You're not missing anything. LEDs that have a high CRI is a relatively new market segment, so the selection is limited, and prices are high. LEDs use the same tricks as fluorescents to reach reasonable CRI levels-- multiple phosphors with different spectra excited by the lamp's primary EM emission. So the potential exists to equal or exceed the best fluorescents. Right now, the consumer LED market is focused on replacing lamps in non critical applications, and thus tend to be rather low color temperature and only modest CRI levels. This situation should improve in the future.

"High" CRI fluorescent tubes are available in color temperatures from 3000 to 6500K, with CRIs between 80 and 90, and at reasonable prices. Right now, this is probably still a good solution for many applications. If the performance of these lamps are not adequate, halogen lamps are the only reasonable alternative. LEDs are not quite there yet.

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A quick check on Wikipedia suggests that below 5000K the Color rendering index is unreliable in the first place. Incandescent lamps have a color temperature of between 2700-3300K and a CRI of 100.

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