Incandescent, halogen, CFL or LED?

Incandescent lamps

Traditional tungsten filament bulbs produce light by using electricity to heat a filament. Light is simply a by-product of this heating process, which makes incandescent lamps an archaic and highly inefficient technology with up to 90% of the energy used by the bulb being converted to heat.


Halogen bulbs

Halogen bulbs are another lighting technology which, while they also use a tungsten filament, last longer than incandescent bulbs. The filament is encased in a small quartz envelope, along with halogen gas, which combines with the tungsten atoms at high temperature as they evaporate. This is then re-deposited on the filament when the bulb cools down, a recycling process that ensures that halogen bulbs last much longer than incandescents. However they become extremely hot and are therefore inefficient.

Compact Fluorescent Lights (CFLs)

CFLs are far more efficient, using less than a quarter of the power to run, and can last up to ten times longer than filament bulbs – but, they contain mercury, a toxic substance that is harmful to people, animals and the earth.

Light Emitting Diodes (LEDs)

For both consumers and business, in light of an increasingly eco-conscious planet and the need to optimise energy consumption, LED lamps offer the best of both worlds, delivering superior energy efficiency, incredible lifespan and an environmentally friendly lighting technology.


Take note

  • Halogen bulbs use a tungsten filament and are considered inefficient as they become extremely hot, losing energy as heat
  • CFLs use less power and last longer than filament bulbs; if broken they may release mercury which is toxic to humans and the environment.
  • LEDs use the movement of electrons to generate light and therefore lose far less energy to heat than other light technologies.


Published as:

By F Mitchell, Drive Control Corporation

Electricity+Control, April 2012 (pgs 56 – 58)

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