Comparison To Other Lighting Technologies
See luminous efficacy for an efficiency chart comparing various technologies.
- Incandescent lamps (light bulbs) generate light by passing electric current through a resistive filament, thereby heating the filament to a very high temperature so that it glows and emits visible light over a broad range of wavelengths. Incandescent sources yield a "warm" yellow or white color quality depending on the filament operating temperature. Incandescent lamps emit 98% of the energy input as heat. A 100 W light bulb for 120 V operation emits about 1,180 lumens, about 11.8 lumens/W; for 230 V bulbs the figures are 1340 lm and 13.4 lm/W. Incandescent lamps are relatively inexpensive to make. The typical lifespan of an AC incandescent lamp is 750 to 1,000 hours. They work well with dimmers. Most older light fixtures are designed for the size and shape of these traditional bulbs. In the U.S the regular sockets are E26 and E11, like E27 and E14 in some european countries.
- Compact fluorescent lamps lifespan may vary from 6,000 hours to 15,000 hours.
- Fluorescent lamps work by passing electricity through mercury vapor, which in turn emits ultraviolet light. The ultraviolet light is then absorbed by a phosphor coating inside the lamp, causing it to glow, or fluoresce. Linear fluorescent lamps have life spans around 20,000 and 30,000 hours based on 3 hours per cycle according to lamps NLPIP reviewed in 2006. The newer rare earth triphosphor blend fluorescent lamps made by Osram, Philips, Crompton and others have a life expectancy greater than 40,000 hours, if coupled with a warm-start electronic ballast. The life expectancy depends on the number of on/off cycles, and is lower if the light is cycled often. The efficacy of these lamps are around 90 lumens/W. The ballast-lamp combined system efficacy for then current fluorescent systems in 1998 as tested by NLPIP ranged from 80 to 90 lm/W. For comparison, general household LED bulbs available in 2011 emit 64 lumens/W, with the best LED bulbs coming in at about 100 lumens/W.
| Cost Comparison | ||||||
|---|---|---|---|---|---|---|
| Incandescent | Halogen | CFL | LED (Generic) | LED (Philips) | LED (Philips L-Prize) | |
| Purchase price | $0.41 | $4 | $4 | $10 | $16 | $30 |
| Electricity usage | 60 W | 42 W | 13 W | 13.5 W | 12.5 W | 10 W |
| Lumens | 860 | 570 | 825 | 850 | 805 | 940 |
| Lumens/Watt | 14.3 | 13.6 | 63.5 | 63 | 64.4 | 94 |
| Color Temperature Kelvin | 2700 | 3000 | 2700 | 3000 | 2700 | 2700 |
| CRI | 100 | 100 | 82 | >75 | 85 | 92 |
| Lifespan (hours) | 2,000 | 3,500 | 8,000 | 25,000 | 25,000 | 30,000 |
| Bulb lifetime in years @ 6 hours/day | 1 | 1.6 | 3.7 | >11.4 | >11.4 | >13.7 |
| Energy cost over 10 years @ 15 cents/kWh | $197 | $138 | $43 | $44 | $41 | $33 |
| Total | $201 | $166 | $55 | $54 | $57 | $63 |
| Comparison based on 6 hours use per day (21,900 hours over 10 yrs) | ||||||
Read more about this topic: LED Lamp
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