Light Emitting Diode (LED)

The LED lamp was developed in the 1960s and is fast becoming the energy-efficient lamp of choice. An LED lamp is a very small light source, 1/4 inch (6.35 mm) or smaller in size. In order to generate a large amount of light, these small dots are clustered together in various configurations. The light waves are only emitted in one direction so the configuration will determine how light is distributed. These lamps require a driver to operate and the color temperature and CRI depend on the lamps selected. LEDs can be either line voltage or low voltage and currently rated to last about 50,000 hours but the life expectancy is expected to increase far beyond that as more efficient LEDs are developed. LEDs come in an almost unlimited number of colors and they have recently been able to produce a white wavelength as well. They are temperature tolerant and durable, but cur­rently carry a high cost. The applications for LED are increasing and the quality is improving. Many feel this will be the energy-efficient lamp of choice in the future.

Fiber Optics

Fiber optic lights send light along a glass fiber and are therefore very delicate. Fiber optic lights are quite expensive and are often used in decorative lighting to create a dramatic effect.

Table 7.2 is a comparison chart developed by the DOE and listed on their energysavers. gov website to show how the various types of lamps compare to one another.

TABLE 7.2 A Comparison of Lamp Types

Lighting Comparison Chart

efficacy

Lifetime

Color rendition index

Color Temperature

Indoors/

Lighting Type

(lumens/watt)

(hours)

(CRI)

(K)

Outdoors

incandescent

Standard Д-type bulb

10-17

750—2500

98—100 (excellent)

2700—2800 (warm)

Indoors/

outdoors

Energy-Saving

Incandescent

Halogen

12-22

1,000—

4,000

98—100 (excellent)

2900—3200 (warm to neutral)

Indoors/

outdoors

Reflector

12-19

2000—3000

98—100 (excellent)

2800(warm)

Indoors/

outdoors

Fluorescent

Straight tube

30—110

7000—24,000

50—90

(fair to good)

2700—6500 (warm to cold)

Indoors/

outdoors

Compact fluorescent lamp

(cfl)

50—70

10,000

65—88 (good)

2700—6500 (warm to cold)

Indoors/

outdoors

Circline

40—50

12,000

Indoors

Light-Emitting Diodes

Cool white LEDs

60—92

25,000—50,000

70—90 (fair to good)

5000 (cold)

Indoors/

outdoors

Warm White LEDs

27—54

25,000—50,000

70—90 (fair to good)

3300 (neutral)

Indoors/

outdoors