Technical Questions

How is the hour rating on a bulb determined?

Lamp manufacturers test large groups of lamps to estimate the average burn time that can be expected. In the lighting industry hour ratings are referred to as Average Rated Life. Some lamps will last longer and some will not last as long as the Average Rated Life but this provides the best estimate.

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Why do my fluorescent lights flicker?

Flickering can be caused by any of the following conditions:

  • The environment is too cold; most ballasts are not designed for temperatures less than 50 degrees. Drafts and moving cold air may cause flickering too. Special low-temperature ballasts are available; ask our Customer Service staff for details.
  • The lamp is not properly installed in the socket. Try removing it and reinstalling it to ensure it is firmly in place.
  • The lamp is at the end of its life and needs to be replaced.
  • The lamp and the ballast wattage requirements are not properly matched to each other.

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What is CRI?

CRI stands for Color Rendering Index and is measured on a scale of 1 to 100. The higher the CRI the better the ability of the light source to render colors accurately. In other words colors will look more “true” and natural. A lower CRI can result in some distortion of the actual color.

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Why choose Compact Fluorescent Lighting (CFL)?

  • CFL technology has several advantages over incandescent lighting technology: it is four times more efficient and lasts up to 10 times longer. It uses about 75% less energy, and produces 90% less heat while delivering more light. In addition, CFLs provide a flicker-free start, soft-white light, are environmentally friendly, and come in a variety of styles. Click here to see our CFLs.
  • Although they are more expensive to purchase initially, you save money in the long run because CFLs use 1/4 the electricity and last up to 10 times as long as incandescents. Energy-efficient CFLs can be used anywhere incandescent bulbs are used: in recessed fixtures, table lamps, ceiling fixtures and porch lights. Make sure to choose the Color Temperature that is right for you; for example: Approx. 2700K = Warm White (looks just like incandescent) and Approx. 4100K = Cool White (white/blue, often higher CRI).

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How do you measure the length of a lamp?

The length of a lamp can also be referred to as the Maximum Overall Length or M.O.L. Most lamps are measured from end to end including the base. Linear fluorescents are an exception; they include the actual socket in their M.O.L. Find more visual information about this in our "Learn How to Measure" article.

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Why does a light bulb turn black?

  • Over the life of an incandescent light bulb, the filament begins to deteriorate and the particles will settle on the inside of the glass. In return the bulb will take on a grayish appearance and a slight decrease in light output may occur.
  • For fluorescent bulbs only, the ends will blacken as the bulb is burned. Each time the lamp is turned on and off the emissions material settles on the inside of the glass. Extreme darkening generally indicates the bulb is about to burn out.

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What is the difference between 120 volt and 130 volt?

  • Line voltage in the United States is 120 volts, however lamps are often manufactured at 130 volts to increase lamp life and to offer protection against power surges. Please note you may use a 130-volt lamp in a 120-volt socket without issue, but you will sacrifice some light output.
  • Rule of thumb: when run on a 120-volt line, a 130-volt lamp may last up to twice as long but can be up to 15% dimmer than a 120-volt lamp.

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How do I know what wattage to use in my fixture?

Whenever replacing a lamp you must check the fixture for wattage and voltage requirements. With an incandescent light fixture, wattage becomes a preference depending on how much light is needed. With fluorescent or high intensity fixtures the wattage is specific to the ballast built in the fixture.

CAUTION: Using the wrong lamp in a fixture could cause the bulb to burnout early and may create a fire or safety hazard.

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What is Kelvin temperature?

Kelvin temperature is often referred to as color temperature. It describes the actual appearance of the light itself. Higher temperatures represent a “cooler” appearance while lower temperatures represent a “warmer” appearance.

  • 2700K – 3000K = Warm White
  • 3500K = Neutral
  • 4100K = Cool White
  • 5000K – 6000K = Daylight

You can learn more about this in our "Color Temperature Scale" article. Our customer service staff can also help you choose the best light for your needs.

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What is a compact fluorescent?

A compact fluorescent is often used as an alternative to a standard light bulb. Compact fluorescents (also called PL twin-tube, CFL twist tube, or BIAX lamps) can be used in table lamps, wall fixtures, and lamp posts. The lamp life is about 10 times longer than a standard light bulb, and they use 3 to 4 times less energy to operate.

Push-in compact fluorescent lamps have a different base (depending on wattage) to reduce the likelihood of using an incorrect ballast.

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What is the difference between medium and mogul base lamps?

Medium base or “standard” base is the most frequent choice in everyday household applications; a standard household bulb has a medium base. Many industrial applications require a mogul base lamp. This base is larger than the medium base. We carry both types of lamps.

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What is the difference between Halogen, Krypton and Xenon bulbs?

Halogen bulbs are normally filled with about 99% inert gas and 1% halogen gas. The inert gas typically used is argon, which creates a yellower light and burns hot. Krypton and Xenon bulbs are a variation of Halogen bulbs. Different fill gases are used to alter their performance and physical characteristics. Krypton bulbs cost more to produce, however, they offer better performance with their long life and a better quality light. Xenon gas is used to create a bulb that produces a whiter light that burns at a cooler temperature. Xenon bulbs have a longer rated life than standard halogen.

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What causes a fluorescent light fixture to hum?

All fluorescent lights require a ballast to function. Both magnetic and electronic fluorescent ballasts give off a slight humming noise; harmonics is the technical term. By design an electronic ballast has reduced harmonics and therefore the hum is less noticeable than when using a magnetic ballast. If the hum is louder than usual the ballast may need to be replaced.

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What is an ANSI code?

An ANSI code is either an alpha or numeric designation that ensures certain specifications such as wattage voltage shape and base. ANSI stands for American National Standards Institute. This organization develops voluntary guidelines and product performance standards for the electrical industry and other industries. Bulbs and fixtures are often imprinted with the ANSI code.

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