Comparing Incandescent and Halogen BulbsThis section compares various aspects of incandescent and halogen bulbs. These aspects include: technology, efficiency, durability, color of light, and miscellaneous pros and cons. Readers can use this information to determine which type of light bulb they prefer, based on various lighting scenarios and general personal preferences.
TechnologyBoth incandescent and halogen bulbs are based on the concept of two parallel metal wires transmitting an electrical current to a tungsten filament that connects them, heating the filament to a point where its heat is reflected as light. Both types of light bulbs also put a glass housing around the wires and filaments to amplify the light that is produced. The major difference between an incandescent bulb and a halogen bulb is the gases that each produces within its glass bulb. The purpose of gas production is the same in that it is meant to slow evaporation of the filament and keep it from rusting. Both incandescent and halogen bulbs go dark when the filament wears out. Incandescent bulbs fill with a mixture of 93 percent argon and seven percent nitrogen, both of which are inert gases. A halogen bulb adds a halogen gas, such as iodine or bromine, creating a chemical reaction that regenerates evaporated tungsten and puts it back on the filament, helping to extend the filament’s life and therefore the life of the light bulb.
EfficiencyOne important consideration in choosing a light bulb is its energy efficiency. Incandescent bulbs are less efficient than halogen bulbs are, using about 90 percent of the energy that they consume to produce heat and turning less than five percent of it into light. The table below provides information on both the luminous efficacy and the luminous efficiency of both types of bulbs. The former is a measurement of how many lumens of light is produced per watt of energy consumer and the latter is a reflection of how much light is produced relative to the maximum luminous efficacy of 683 lumens per watt.
Luminous Efficacy (lm/W)
|40 W Incandescent||12.6||1.9%|
|60 W Incandescent||14.5||2.1%|
|100 W Incandescent||17.5||2.6%|