What is a Halogen bulb?

Halogen is a type of incandescent lamp. It has a tungsten filament just like a regular incandescent that you may use in your home, however the bulb is filled with halogen gas. When an incandescent lamp [one which produces light by heating a tungsten filament] operates, tungsten from the filament is evaporated into the gas of the bulb and deposited on the glass wall. The bulb fails or "burns out" when enough tungsten has evaporated from the filament so that electricity can no longer be conducted across it. The halogen gas in a halogen lamp carries the evaporated tungsten particles back to the filament and re-deposits them. This gives the lamp a longer life than regular non-halogen A-line incandescent lamps and provides for a cleaner bulb wall for light to shine through.

Why do halogen bulbs last longer than incandescent ones?

The life of incandescent and halogen light bulbs, referred to as tungsten filament lamps, is limited by the state of the filament. The filament is the wire inside the bulb that produces light when heated. The light bulb will not work if the filament is broken which may occur as a result of the application of force, such as dropping the bulb, or by lack of tungsten in a particular area over the filament. During the operation of tungsten filament light bulbs, tungsten from the filament evaporates into the gas inside the light bulb. When the tungsten comes in contact with a cool surface it will condense. Often, with incandescent products, the tungsten condenses on the bulb wall. Because the tungsten is re-deposited on the wall instead of the filament, the filament grows thin over time. Eventually, there will be a point on the filament with so little tungsten that the filament will break and the light bulb will stop working.

Halogen light bulbs have a special gas inside their bulb containing halogens. The halogen gas facilitates the "halogen regenerative cycle" which means that the halogens carry the evaporated tungsten back to the filament instead of allowing it to deposit on the bulb wall. By placing the tungsten back on the filament instead of the wall, it delays the filament breaking due to lack of tungsten. Although the halogen cycle significantly increases the life of the light bulb, it cannot last forever because the halogen gasses cannot place the tungsten on a specific spot on the filament to avoid any place having too little tungsten and breaking.

What is a lumen and is there any relationship between lumens and wattage?

A lumen is the unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source having an intensity of one candela. There is no direct correlation between lumens and watts because other variables may affect the relationship, such as lamp design life and fill pressure. Efficacy, given in lumens per watt, is the total luminous flux emitted by a lamp divided by the total power input.

Do the electrical characteristics of an incandescent bulbs change significantly over its life?

No. In general, the electrical characteristics of tungsten filament bulbs [incandescent and halogen] do not change significantly over their life. However, as the bulb burns, tungsten evaporates and hot spots develop along the filament. This has the effect of slightly increasing filament resistance. At constant voltage, the bulb current will decrease slightly over time. The magnitude of change depends on the bulb design but is on the order of a few percent.

Halogen lamps are slightly more stable than incandescent bulbs over their life. The "halogen cycle" captures the evaporated tungsten that burns off of the filament and re-deposits it on the filament surface. The result is that the electrical characteristics of the bulb - including the bulb current - change very little over life.

My incandescent bulbs have been failing earlier than the specified life.
Why is this?

Rated life is the median life of a sample group, so by definition some lamps will not achieve the full rated life. In addition, incandescent lamp life can be shortened by vibration or shock and supply voltage swings. If a bulb is going to be in an environment where it is exposed to vibration or shock, such as a garage door opener light or ceiling fan, you should try to use a lamp with a stronger filament. Keep in mind that stronger filament bulbs will be less energy efficient.

Another cause of continuing general incandescent lamp failure [other than leaving them on all the time] is high voltage. While utilities usually do a pretty good job of voltage regulation, they sometimes have little control. State regulatory boards allow them certain specified leeway because of anticipated load, local load peaks, and other criteria. The allowable limits are usually in the order of ten percent, which on your nominal house voltage of 120 volts would allow a range from 108 to 132.

Incandescent bulbs are very sensitive to voltage. A lamp rated at 120 volts, for example, would only last 1/2 of rated life if subjected to 125 volts or 1/3 of rating if the average voltage applied were 130 volts.

The first thing you should do is to keep track of how long the worst offenders are lasting. How long are your lamps burning? Be sure not to count the time that they are turned off. Typical incandescent bulbs are rated at 750-1000 hours, meaning approximately 2-1/2 changes per year [at about 5-7 hours per day]. The next step may not be easy and should only be undertaken by a licensed electrician. The only way to determine the average voltage your bulbs are experiencing is to attach a recording voltmeter to the circuit you are testing so that it records only when your lights are on. If your electrician determines that you are receiving higher than rated voltage you will need to contact your electric utility to fix it.

Is voltage important in the operation of bulbs?

Yes. For best operation, it is very important that the designated voltage marked on your bulb correspond to the circuit voltage on your electric line or outlet. Thus, a 120-volt bulb should be used on a 120-volt current. Any appreciable variation from this will cause wide variation in the life and efficiency of the bulb. For example, operating bulb just five-[5] volts over the recommended voltage, may reduce its life expectancy by up to 40%

What is meant by "dimming" lamps?

Typically, dimming is defined by a percentage, e.g., 10% dimming, 50% dimming, etc., but this percentage can be applied to several different lamp parameters:
• Lamp Voltage    • Measured Lumen Output
• Lamp Power      • Perceived Lumen Output

Usually, dimming refers to the reduction in measured lumen output. The percentage can also be confusing. For example, "10%" can mean 10% below full lumen output or 10% of full lumen output. By and large, the latter method is used. Therefore, we say a certain system can "dim to 10%" meaning, for example, a 2000 lumen source is reduced to 200 lumens.
To eliminate some of this confusion, another method can be used called dimming ratio. This takes the guesswork out of it. Dimming ratio is the ratio of rated lumens to actual or minimum lumens. In the above example, the dimming ratio is 2000:200 or 10:1 [10 to 1].

Incandescent & Halogen Lamps
How is dimming accomplished? How does one reduce the lumens?
By controlling the voltage to the lamp. If the voltage is reduced, the lamp current and resulting lamp power are reduced. The voltage is reduced by decreasing the amplitude of the 60-cycle waveform or by turning off the applied voltage for part of the cycle [called phase control]. The former method typically uses an adjustable transformer [variac or autotransformer]; the latter is typical of solid state controls [wall dimmers and the like].

Why do incandescent bulbs darken over their life?

During the operation of incandescent light bulbs, tungsten from the filament evaporates into the gas inside the light bulb. When the tungsten comes in contact with a cool surface it will condense. Often, with incandescent products, the tungsten condenses on the bulb wall. Over time, tungsten will accumulate on the walls of the bulb and cause darkening of the bulb.

Halogen light bulbs eliminate the bulb darkening because halogen light bulbs have a special gas inside their bulb containing halogens. The halogen gas facilitates the "halogen regenerative cycle" which means that the halogens carry the evaporated tungsten back to the filament instead of allowing it to deposit on the bulb wall.

What is the effect of tungsten filament aging on current?

As tungsten filaments age, grain boundary etching and the development of porosity [near the end of life, a cross-section of the filament resembles Swiss cheese] within the filament occurs. Because of this, the resistance increases during life so the current decreases at constant volts. However, the current decrease is not significant and therefore would not affect the lamp in normal operation.

How much heat or IR is radiated by incandescent bulbs?

About 90% of all energy emitted by tungsten filaments [including those in halogen lamps] is infrared or radiant heat. The way to decrease heat from your lamps is to use lower wattage bulbs.

What are the benefits of dimming an incandescent lamp?

Using a dimming switch on an incandescent light bulb will not only reduce the energy consumption of the lamp, but also it will extend the life of the lamp. A 10% reduction in voltage [12 volts] in a lamp designed for 120-volt operation will extend the life almost 400%. However, light output will be reduced. For example, if you use a 100-watt standard household incandescent dimmed by 10%, you'll save 10% energy, extend the life of the lamp, but the light bulb would have a diminished light output.

How does a light bulb actually work?

Basically, an incandescent Bulb is a simple device - just a tungsten wire sealed in a glass tube. The electric current passing through the wire heats it to incandescence, and the wire produces light. Suppose you took a dark piece of metal. If you heat it in a furnace, it becomes hot and radiates heat, but at first shows no visible effects. As temperature is increased, it turns a dull red, therefore emitting not only heat, but also some light. As the temperature is increased further, it turns to a cherry red, then yellow, and at temperatures of about 4600 F, it radiates a bright, nearly 'white-hot' light. For the incandescent lamp, energy is supplied electrically to make up for the energy, which is radiated as heat and light.

What is the Color Rendering Index [CRI] and why is CRI important?

The color rendering of a light source describes that source's ability to accurately render the colors of perceived objects - people and things. As a general rule, the higher a light source's Color Rendering Index [CRI] number, the better the bulb will make things appear.

How much does the energy cost to run a light bulb?

If you know the wattage and price of your electricity then you can figure out the cost over time with this formula:

Energy Cost to run =  

wattage x cost per kilowatt hour x average rated life 
                                   1000

Note the cost per kilowatt hour is available from your utility. For example, the cost to run a 100 watt lamp with an average rated life of 750 hours at a rate of .10/kWh would be: 

Cost =   100 x .10 x 750   which works out to be $7.50. 
                     1000   

Is it true that it is cheaper to leave lights on than to turn them on and off several times during the day?

This is not correct. There is not a higher energy requirement for starting lamps that outweighs running them for any period of time. Although shorter burning cycles [more "on and offs"] can reduce lamp life, it is always better to turn lights off when they are not in use. Since the cost of the electricity [even in the cheapest markets] is so much more that the cost of replacing lamps a little sooner, you would maximize your savings by turning off the lamps when you don't need the light.

What is UL?

Underwriters Laboratories Inc. [UL] is an independent, not-for-profit product-safety testing and certification organization. UL is the leader in product-safety testing and certification within the United States. UL is one of the most recognized, reputable conformity assessment providers in the world. Their services extend to helping companies achieve global acceptance, whether for an electrical device, a programmable system, or an organization's quality process.

What is Energy Star?

ENERGY STAR is a voluntary partnership between the U.S. Department of Energy, the U.S. Environmental Protection Agency, product manufacturers, local utilities, and retailers. Partners help promote efficient products by labeling with the ENERGY STAR logo and educating consumers about the unique benefits of energy efficiency products. ENERGY STAR-labeled products use less energy than other products, save you money on utility bills, and help protect the environment. You can find out more about ENERGY STAR by visiting their website at
http://www.energystar.gov/.

Does turning an incandescent light bulb on and off affect its life?

Generally flashing an incandescent light bulb will not affect the life

Why does one light in a three-way always burn out more rapidly than the others?

Three-way light bulbs have two filaments, the small filament is for the low setting, the larger filament for medium, and both filaments light together for the third and highest setting. Most people tend to leave a light bulb on a low position, so the low wattage filament burns out first. This results in a loss of the lowest and highest settings in a three-way light bulb

If I am using two 75 watt light bulbs do I have the same or more illumination as a 150 watt light bulb?

One standard 75 watt light bulb produces 1210 lumens, or units of light, therefore, two 75 watt light bulbs generate 2420 lumens. One 150 watt light bulb generates 2580 lumens, so, you get more light from one 150 watt than two 75 watt light bulbs. Why? The 150 watt filament gets hotter than the 75 watt filament [about 100 degrees F hotter]. The hotter filament the more light is produced.

Why can’t some décor bulbs be burned base up?

When a décor light bulb is burned base up, the heat from the filament rises into the base. For medium based décor light bulbs this will cause the glue holding the base and the glass together to lose its adhesive. Some manufacturers offer a medium base and a candelabra base fan light which can be burned base up. These fan light bulbs are manufactured with a more costly cement in the base, which can withstand higher temperatures and not lose their adhesive. See light bulb manufacturers’ package for operating position.

Can I use a higher wattage light bulb than the fixture recommends?

No, fixture manufacturers recommend maximum wattage light bulbs to prevent overheating of fixture’s sockets and wiring. However, if you need a brighter light it is possible to use the Longlite QL-3 power controllers in conjunction with a Halogen light bulb. The QL-3 power control system provides the same amount of visible light at reduced wattages.

Do halogen light bulbs burn hotter than standard incandescent light bulbs?

NO. Temperature is a function of wattage [measure in BTU] and efficiency.

What happens if non-dimmable compact fluorescent are used on a dimmer?

The dimmer would overload the ballast and possibly start a fire.

Are QL-3 Power Controllers Reusable?

N0 - After the light bulb fails, unscrew the bulb as normal and discard the bulb and QL-3 device, which will stay affixed to the bulb’s base.

Is the Three-Way Bulb Converter reusable?

Yes - simple reuse the converter after the light bulb has failed.

Will the QL-3 Power Controller work on compact fluorescent bulbs?

NO, but they will work if the compact fluorescent bulb is DIMMABLE. See light bulb manufacturer’s packaging.

Which QL-3 model should I use?

Identify the energy savings and life extension you wish to achieve and select the QL-3 model.

Can I use QL-3 outside?

QL-3 Power Controllers can be used indoor or outdoor. However, some light bulbs need external protection from water. Please see light bulb manufacturers’ information regarding indoor/ outdoor usage.

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How do I know if the QL-3 Power Controller is working?

If the lamp lights, then the controller is working. You can also review your energy bill - the energy savings begin immediately.

How does the QL-3 System use less power and still burns as brightly?

Depending on the QL-3 model, the voltage across the filament is being limited, resulting in less consumed wattage and longer life. The SIDAC microchip fine-tunes the reduced input voltage so that the human eye can not see a difference in visible light levels. Studies by the Rensselaer Polytechnic Institute have proven that the detection threshold for reduced light level is @ 80% of the initial luminance level.

To purchase, please visit The EnergySuperMarket