ENERGY EFFICIENT LIGHTING

小股民

LUMENS AND WATTS

When buying light bulbs, most people think of “watts” as a measure of brightness.  We know, for example, that a 100 watt incandescent bulb provides a lot of light, while a small 7 watt bulb can serve only as a night-light or a decorative light for the festive season.

In reality, the watt is a measure of how fast energy is used, not of light output.  A 40 watt bulb uses 40 watts of electricity no matter what type of bulb it is.  But the amount of light produced by the bulb can vary significantly depending on its type.

Light output is measured in “lumens”.  A 100 watt standard incandescent bulb produces about 1,680 lumens.  A 26 watt compact fluorescent lamp produces about 1,700 lumens.  While the two bulbs produce virtually the same amount of light, the compact fluorescent lamp does so using only a quarter of the energy consumed by the standard incandescent lamp.

The following table can help you when you are replacing regular bulbs with compact
fluorescents:

INCANDESCENT BULBS		CFLs WITH ELECTRONIC BALLAST
Watts	Lumens	* Watts	Lumens
40	495	10	520
60	855	15	950
75	1,170	20	1,200
100	1,680	26	1,700
150	2,650	42	2,650

*    Based on the GE Spiral and Mini Spiral CFL’s.