Halogen Bulb FAQS
Q) What makes a light bulb a halogen light bulb?
A) A halogen gas (such as iodine or bromine) has been introduced into the glass envelope.
Q) Why add halogen gas to the other gases?
A) It increases the rated life of the lamp.
Q) What is the rated life of halogen light bulbs?
A) Depending on the lamp and the conditions under which it is being operated the rated life can be somewhere between 8,000 and 20,000 hours.
Q) What does the term, "rated life", of a light bulb mean?
A)It signifies the time at which 50% of a large quantity of these lamps will have burned out. This means that 50% of these lamps will burn out before the "rated life" and 50% will burn out after the "rated life". It does not mean that every one of the lamps will last at least that long.
Q) Is this definition of "rated life" true for all types of light bulbs or just halogen light bulbs?
A) This is the standard definition for all lamps.
Q) How does a halogen light bulb create light?
A) By passing electricity through a filament until the filament reaches the point of "incandescence", the point at which the filament gives off light in addition to heat.
Q) Do I have to be concerned about touching a halogen light bulb with my bare hands?
A) Yes, unlike xenon lamps, some halogen lamps (such as JC bipin lamps and double-ended quartz halogen lamps) should not be handled with bare hands. The oil from your hands will almost always cause the halogen lamp to fail prematurely. (Caution: always wait for it to cool down before touching it.)
Q) Are halogen light bulbs relatively cool to operate?
A) No, halogen lighting, in general produces a good deal of heat.
Q) Do halogen light bulbs operate hotter than xenon light bulbs?
A) Yes, they do. (For an in-depth comparison of xenon and halogen lighting, check out article Xenon vs. Halogen Lighting.)
Q) Are halogen light bulbs considered to be energy efficient?
A) Not really. Because they create light in much the same way standard incandescent light bulbs create light, they are not generally considered to be energy efficient. However, in general, halogen light bulbs are considered to be 10% to 20% more energy efficient than either standard incandescent or xenon light bulbs but less efficient than fluorescent light bulbs.
Q) Do halogen light bulbs require a ballast to operate?
Q) Do they require a transformer to operate?
A) If the halogen light bulb is rated at 12 volts or 24 volts (low voltage), then it requires the appropriate transformer. If, however, the halogen light bulb is rated at 120 volts (line voltage), then it does not require a transformer to operate.
Type of Light
Q) What "kind of light" is given off by halogen light bulbs?
A) The light is often described as a "crisp, white light", light that is a bit cooler in appearance than the light coming from a xenon lamp.
Q) Do they provide good color rendition of the objects they are lighting?
A) Absolutely. Halogen is considered to have a color rendering index (CRI) of 100, which is considered perfect - like the sun.
Q) Where should I consider using halogen lighting in my home?
A) It can be effectively used in accent lighting, display case lighting, and recessed downlighting.
Q) Are halogen light bulbs dimmable?
Q) Will dimming reduce the amount of energy it consumes?
Q) Will dimming increase its average life?
A) Yes. A pilot test performed by Lutron, a major manufacturer of dimmers, suggests that halogen lamps will have an expected lamp life similar to that of other incandescent lamps when dimmed. As an example, one type of halogen lamp with a rated life of 2000 hours dimmed to 25% has a life extension of about four times that of a non-dimmed lamp.
Q) What kind of dimmer should be used with halogen light bulbs?
A) If the low voltage halogen lamp (12 volts or 24 volts) is powered by an electronic transformer, then the dimmer should be one that is designed to control an electronic low voltage transformer. If the low voltage lamp (12 volts or 24 volts) is powered by a magnetic transformer, then the dimmer should be one that is designed to control a magnetic low voltage transformer. If, however, the halogen lamp is line voltage (120 volts), then the dimmer should simply be a line voltage dimmer.
Lamp Base Types