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Light Bulbs at a Glance

  By: Jonathan Z. Kremer

(Incandescent)  (Halogen)  (Fluorescent-tubular)  (Compact Fluorescent)  (Metal Halide) 

(LED - SSL)  (Mercury Vapor)  (High Pressure Sodium)  (Low Pressure Sodium)

Life span: 700-1000 hours
Pros: cheap; gives a pleasant warm light that most people like,
Cons: least efficient of all the bulbs
Efficiency: 7 - 24 lumens per watt
Uses: General lighting
Notes: can heat up, therefore care must be taken near flammable material, short life span.


Life span: 2,000 - 4,000 hours
Pros: more efficient than incandescent bulbs; bright light
Cons: burns very hot; more expensive than incandescent
Efficiency: 12 - 36 lumens per watt

220v tubes - General lighting, floodlights

12V - accent lighting, task lighting

Notes: must be careful using these bulbs near flammable materials or in closed places.


Fluorescent (tubular)
Life span: 10,000 - 20,000 hours
Pros: bulb burns cooler; very efficient; can come in various CRI ratings; comes in different color temperatures
Cons: not dimmable; fixtures are more costly; known to flicker at times.
Efficiency: 33 - 100 lumens per watt
Uses: General, floodlights
Notes: frequent switching on and off reduces efficiency.


Compact Fluorescent
Life span: Up to 10,000 hours  
Pros: efficient  
Cons: cost of bulb; sometimes they can't physically fit; to replace incandescent bulbs  
Efficiency: 44 - 80 lumens per watt  
Uses: General lighting  
Notes: frequent switching on and off reduces efficiency.  


Metal Halide
Life span: 6,000 - 10,000 hours  
Pros: extremely efficient; give a brilliant light; bulbs come in different color temperatures; good color rendering.  
Cons: cost of both fixture and bulb; burns hot  
Efficiency: 60 - 125 lumens per watt  
Uses: places where a lot of light is needed such as outdoor areas and retail shops. Used frequently in sports arenas, stadiums, auditoriums, and convention halls  
Notes: not to be used near flammable materials. Bulbs usually must burn in a certain position.  


Life span: 30,000 - 80,000 hours (100,000 hours)  
Pros: High durability - no filament or tube to break; long life span; low power consumption; low heat generation  
Cons: High cost of bulb (in the meantime)  
Efficiency: 30 - 60 lumens per watt (200 lumens per watt)  
Uses: wide variety of uses including general lighting, accent lighting, and decorative lighting  
Notes: LED technology is relatively new, and is changing every day. The quality and efficiency of the bulbs are improving all the time.
The ratings in parentheses (above) are the predicted improvements which are expected to come about within the next few years.


Mercury Vapor
Life span: 1600 - 6000 hours  
Pros: more efficient than incandescent and halogen; gives a nice color to landscapes.  
Cons: lowest efficiency of the HID type bulbs; dims rapidly; bad color rendering  
Efficiency: 20 - 63 lumens per watt  
Uses: landscape illumination, outdoor lighting  
Notes: produce a blue-green light  


High Pressure Sodium
Life span: 18,000 - 24,000 hours  
Pros: extremely efficient, long lasting,  
Cons: bad color rendering, produces yellowish light; slowly lose their brightness with time  
Efficiency:  60 - 140 lumens per watt  
Uses: very popular for indoor horticulture, outdoor and industrial applications  
Notes: Please see note at bottom.  


Low Pressure Sodium
Life span: approximately 16,000 hours  
Pros: one of the most efficient bulbs there is, long life span.  
Cons: worst color rendering (monochromatic) of all the bulbs, initial setup can be costly  
Efficiency:  90 - 180 lumens per watt  
Uses: security lighting or indoor applications like stairwells  
Notes: monochromatic -  all colors under this light appear black, white, or shades of gray. Please see note at bottom.  



Please Note:

If sodium lamps break, ventilate the area where breakage occurred. Clean-up with vacuum cleaner or other suitable means that avoids dust generation. Take usual precautions for collection of broken glass. Clean-up requires special care due to the fact that sodium reacts with the moisture on the skin and in the air. Materials from broken lamps should be treated as for spent lamps. To avoid the risk of sodium reaction when disposing of spent lamps, the following procedure should be followed:
· Before commencing, operator should be outfitted with appropriate face mask, gloves and apron.
· Place lamp(s) in a dry, high container and break lamp(s) into small pieces in a dry atmosphere and in a well ventilated
· From a safe distance, pour enough tap water into container to cover all materials.
· After a few minutes, the reaction of the sodium with the large quantity of water will produce a mild sodium hydroxide
solution which may be disposed of in accordance with applicable local regulations.

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