The Facts of Lighting

Light Source		Average Life (Hours)		Lumens per Watt
Incandescent		750-2500		10-20
Tungsten-Halogen		1000-3500		18-22
Self Ballasted Mercury Vapor		12000-16000		25-33
Mercury Vapor		24000		40-63
Fluorescent		7500-24000		60-110
Metal Halide		7500-24000		85-110
High Pressure Sodium		24000		80-140
Low Pressure Sodium		12000-18000		100-200

Some Additional Facts Of Lighting
One gallon of #6 fuel oil is required to produce 15 kilowatt-hours of electricity. This amount of power would be consumed by 150 100-watt incandescent lamps operating for one hour.

One watt of air conditioning is required to offset the heat of one watt of light. Thus energy-saving lamps reduce air conditioning cost watt-for-watt.

Fluorescent lamps produce approximately five times the light of standard incandescent lamps -- watt-for-watt.

High pressure sodium lamps produce more than twice the light of mercury vapor lamps -- watt-for-watt.

Low pressure sodium lamps are the most energy-efficient of all lamps, producing approximately three times the light of mercury vapor lamps -- watt-for-watt.