Interior Lighting for Designers

TABLE 4

EFFICACY OF ELECTRIC LIGHT SOURCES

Lamp Type

Wattage

Range

Initial Lamp

Efficacy (Lumens

per watt)

Color

Temperature

in Kelvin (K)

Color

Rendering

Index (CRI)

Design Life

(Hours)

Incandescent 6–1,500 4–24.5 2700–2800 100 750–4,000

Tungsten-halogen 5–1,500 10–22 2900–3100 100 1,000–6,000

Fluorescent 4–215 10–104.5 2700–7500 53–95 6,000–24,000+

Compact fluorescent 5–80 28–76 2700–4100 81–82 6,000–14,000

Mercury vapor 40–1,000 19–59 3300–5900 15–52 12,000–24,000+

Metal halide 32–1,500 35–100 3000–4400 65–96 3,000–20,000

High-pressure sodium 33–1,000 31–127 1800–2800 22–85 7,500–24,000+

Low-pressure sodium 18–180 58–185 1740–1750 0 14,000–18,000

APPENDIX