Technology

Description

Strengths

Weaknesses

Recommendation

Compact Flourescent (CFL)

A modified technology from fluorescent with the same strengths and weaknesses as flourescent.
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See Fluorescent

See Fluorescent

• As a retrofit, they are a direct screw-in replacement for incandescent lamps allowing use of incandescent fixtures without incandescent lamps (the ballast is in the lamp base)
• Energy-savings, except when used for lights that aren’t on very long

Flourescent

Widely considered the energy efficient alternative to incandescent, fluorescent uses a ballast to start the lamp. This is where your inrush current comes from. An arc lights the gas. Once the gas is glowing, the ballast regulates the current to keep the arc at peak efficiency.
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• High operational efficiency
• Available in many sizes, voltages, and fixtures
• Relatively fast start, many control options
• Relatively low cost
• Everyone’s familiar with it
• Good diffusion makes it excellent for general lighting

• Requires time to overcome initial energy use
• Mediocre color rendition

• Environments where the lights tend to stay on and color rendition is not important

Halogen

Halogen technology is a variation of incandescent. The lamps are filled with halogen instead of argon. Halogen causes the carbon to deposit on the filament, instead of the bulb. Consequently, the bulb can burn hotter.
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• Light output is almost constant through life of lamp
• Whiter light with more lumens per watt
• Excellent color rendition
• Makes new lamp/shade configurations possible vs. incandescent options

• Costs more than incandescent
• Hotter lamp is an issue in some applications

• Where color rendition is critical
• Where lamp/shade configurations solve application problems

HID

Metal halide, sodium, and mercury vapor are the three general variations of HID. As with fluorescent, an arc causes the gasto glow. It’s “high intensity” because the combination of closely spaced electrodes and high-pressure gas result in high temperatures and high release of radiant energy from metal in the gas.
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• Produces visible light without phosphors, so less color distortion than fluorescent
• Good diffusion

• Good diffusion
• Relatively slow start (several minutes to full output)
• Limited dimming abilities
• Each lamp configuration (type/wattage) needs a specific ballast

• Large areas that need general illumination
• Common uses include in warehouses and factories

Incandescent

Sometimes incandescent lighting is more energy-efficient than fluorescent. Overall energy efficiency depends on how long the lights remain on. Incandescent lamps have minuscule inrush current, thus it is optimal for short term operation.
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• Low startup loss (inrushcurrent)
• High color rendition
• Familiar to everyone
• Inexpensive
• Control flexibility
• Numerous aesthetic options

• Low operational efficiency
• Carbon build up on argon filled bulb diminishes output over time
• Heat output adds to cooling load
• Overly restrictive new laws causing demise, making lamp replacement an issue

• Where color rendition and/or white light are critical
• Where usage is brief, such as closets or task lighting

LED

LEDs produce a directional light. Color rendition is between incandescent and fluorescent.

• High efficiency
• Long lifespan
• Rugged
• Operating costs are a fraction of alternatives
• Instant on
• Runs cool

• Expensive (costs are coming down)
• No diffusion
• The market is not yet fully developed

• Where directional lighting is appropriate and fair color renditionis acceptable—if the applicable fixtures exist
• Unsuitable for general illumination

Xenon

This variation of incandescent uses xenon gas.

• Whiter than halogen
• Color rendition so high; nearly identical to daylight
• Produces twice the light of halogen with 2/3 the energy.

• Expensive
• Fewer fixture choices than halogen

• Environments where the lights tend to stay on and color rendition is not important