Halogen Lights
Commonly used as down-lights or spotlights, however some high power fixtures also use them. Some operate on low voltage (commonly 12 Volts). These lamps are commonly wired via a transformer to normal 240 Volt mains.

Advantages

• More energy efficient than incandescent globes, but falls a long way short of either Fluorescent or Compact Fluorescent lights.
• 240 Volt versions are ideal for use in situations where large areas are to be illuminated.

Disadvantages

• Often the 12 Volt lights are mounted directly in the ceiling. If there is insulation in the ceiling, this needs to be removed around the globe and transformer, thereby effectively reducing the room's thermal insulation. As mentioned above, it is common for a number of these to be fitted in a room and each installation degrades the thermal insulation of the room further.
• 12 Volt versions have a fairly narrow beam width, so to adequately light a room you may need quite a number of them.
• Internal gas is a halon, which is environmentally unfriendly.

Safety Warning

• Some lamps, especially 240 Volt versions are designed to operate at 500Watts or more and require adequate ventilation.
• To avoid the risk of fire all halogen lamps must be installed and used strictly in accordance with the manufacturers specifications.
• Lamps have been known to explode, causing injury and should be operated with a glass filter covering the filament.
• These lamps emit UV-B and should be operated with a glass filter covering the filament.
• Lamps should be disposed of carefully due to the harmful nature of Halogen.

Halogen: A hydroxide of bromine, chlorine or iodine.

Halon: Bromine-containing compounds with long atmospheric lifetimes whose breakdown in the stratosphere causes depletion of ozone.