Most efficient lighting
 

You may be surprised by the efficiency of different light sources, ranked by Lm/W look at these sources:

• 200 Low pressure sodium
• 150 Metal Halide
• 100 28w t5 florescent tube
• 93 36W t8 florescent tube
• 60 cfl light
• 26-70 LED (Very directional)
• 24 quartz halogen
• 15 standard incandescent

I have actually seen 35 watt metal halide lamps. They make very good outdoor lighting for constant on/long term on situations.

Neat stuff. Where did you get this from?

PS: Welcome to ecorenovator!

a quick google search got me this page for the numbers. However it can be surprising what people assume vs. reality.

Very nice comparison. I always wondered about industrial lighting.

are those all "same wattage" bulbs?

My understanding is that all of them have different spots where they are most efficient.

And what was a 'prototype' white LED back in 2006 is pretty standard now. So, LED would be up over a 100 and with a lens, you can disperse the light in many different patterns.

I thought metal halide was more like 65-115 lm/W.

Another consideration is quality of light. I do not like the light produced by low pressure sodium fixtures for indoor use.

the reason I ask is that I'm under the impression that for most single lamps, lumens/watt falls off as you increase wattage.

ie: a 25 watt bulb is not 1/2 the brightness of a 50 watt bulb (in incandescent)

in comparison: if you go from 20 watts of LED lighting, up to 50 watts of LED lighting, you have increased the number of emitters, not just the wattage. The same holds (more or less) true for FL tubes-- a 4ft, 40w tube is putting out about the same Lumens/watt as a 2ft 20w tube (from my recollection) but my memory tells me that a 500w metal halide is not twice the brightness of a 250w metal halide, nor are 5 x 100w metal halides the same brightness as 1x500w metal halide.

Still, the comparison of different technologies is interesting, at least.

I'd like to see an additional column added for embodied energy and toxity. ie: it is pretty cheap and easy to build an incandscent bulb, with little toxicity. It is expensive (for now) to build an LED. We all know which lasts longer and which is more efficient, but if you are looking at using one vs the other for a light that is only one for a few hours/year (in theory)... at what point is there true break-even?

I suppose that the issue is even more complicated when you talk about heavy metals found in halides or florescent lights. The costs of disposal/recycling or pollution are much higher for those lights (around here, they are all going to end up in landfill or burn-pile. I no longer buy floro tubes because of this problem).

startup time is another good column. A CFL that takes 4 seconds to fire up isn't a good candidate for a motion-detector light. A metal halide pendant that takes 30-60 seconds to full-brightness would be absurd in a garage door opener, or as a refrigerator light (just to pick obvious failures). In an office or workshop, it might not be a problem to wait a minute until you get full-intensity, and MH lighting can be had in very pleasing CRI (color rendering index?) values.

Cree LED's have reached over 200 lumens per watt,earlier this year, but are not yet on the market, but several emitter manufacturers are selling lamps at over 100 w/l. The GE and Philips lamps that are being sold in the box stores are way overpriced.
But LED's pay for themselves in off grid situations and in situations where changing burned out lamps is expensive. As far as I can tell LED's are the lamp of the future. We use them for most of our lighting and are completely satisfied with them.