I posted this on my Architectural Lighting Blog and since LEDs have been making the new in terms of luminous efficacy (lumens of light output per watt of power consumption), I figured I’d post it here too.
Borrowing a page (almost literally) from wikipedia here are some typical luminous efficacy numbers for various light sources since this seems to come up in lighting circles. 
Luminous Efficacy & Efficiency Examples
| Category | Type | Overall luminous efficacy (lm/W) |
Overall luminous efficiency |
|---|---|---|---|
| Combustion | candle | 0.3 | 0.04% |
| Incandescent | 5 W tungsten incandescent | 5 | 0.7% |
| 40 W tungsten incandescent | 12.6 | 1.9% | |
| 100 W tungsten incandescent | 17.5 | 2.6% | |
| glass halogen | 16 | 2.3% | |
| quartz halogen | 24 | 3.5% | |
| high-temperature incandescent | 35 | 5.1% | |
| Fluorescent | 5–24 W compact fluorescent | 45–60 | 6.6%–8.8% |
| 34 W fluorescent tube (T12) | 50 | 7% | |
| 32 W fluorescent tube (T8) | 60 | 9% | |
| 36 W fluorescent tube (T8) | up to 93 | up to 14% | |
| 28 W fluorescent tube (T5) | 104 | 15.2% | |
| Light-emitting diode | white LED | 26–70 | 3.8%–10.2% |
| white LED (prototypes) | up to 150 | up to 22% | |
| Arc lamp | xenon arc lamp | 30–50 | 4.4%–7.3% |
| mercury-xenon arc lamp | 50–55 | 7.3%–8.0% | |
| Gas discharge | high pressure sodium lamp | 150 | 22% |
| low pressure sodium lamp | 183 up to 200 | 27% | |
| 1400 W sulfur lamp | 100 | 15% | |
| Theoretical maximum (monochromatic 540×1012 Hz, approx. 555 nm, green) |
683.002 | 100% |
If you want a good explanation of luminous efficacy, click here read the full definition at wikipedia
April 15, 2009 at 8:42 am |
The topic is quite trendy on the Internet at the moment. What do you pay attention to while choosing what to write about?