4. Summary - Lamp Type Pros & Cons

Comparison between different lamp types:

I. INCANDESCENT LAMPS

Models:
* Standard A-bulbs and T-bulbs
* Decorative (globe, flame, tinted etc)
* Reflector & PAR

Advantages:
+ Bright point light source
+ Good quality and performance
+ Natural golden-white light
+ Continuous spectrum
+ Highest colour rendering (CRI 100)
+ Lights up immediately
+ Can be used at both freezing and hot temperatures
+ Full compatibility with existing luminaires
+ Fully dimmable on any dimmer
+ Light gets warmer and more candle-like when dimmed
+ Highest Power Factor (1.0)
+ Contains no mercury (and no lead solder after 2006)
+ Easy to produce, use and recycle
+ Low purchase price

Disadvantages:
- More heat than light
- Short lifetime, 1000 hours (Long Life lamps 2500-7500 hrs, at reduction in output)
- Sensitive to voltage fluctuations
- Sensitive to vibrations (except Rough Service bulbs)

II. HALOGEN LAMPS

Models:
* Low voltage halogen minibulbs for spotlights
* Halogen minitubes for floodlights
* Halogen retrofit lamps with outer bulb and scew base
* Halogen retrofit reflector and PAR lamps
* Halogen retrofit Energy Saver bulbs & reflector lamps (new)
* Halogen retrofit bulbs with xenon gas filling (new)
* Halogen retrofit bulbs with IR coating and integrated transformers (new)

Advantages:
+ 10-50% more light than incandescent
+ Bright point light source
+ Good quality and performance
+ Continuous spectrum
+ Highest colour rendering (CRI 100)
+ Sunny white light
+ Fully dimmable on any dimmer
+ Gets warmer when dimmed
+ Full compatibility with existing luminaires
+ Light up immediately
+ Work as well in low as in high temperatures
+ Highest Power Factor (1.0)
+ Do not lose output with age
+ Contain no mercury or other toxic chemicals

Disadvantages:
- Low to medium low efficiency
- Risks due to high operating temperature
- Models with clear bulb or tube may be very glaring
- Medium short lifetime (2000 - 3000 hours, some reflector lamps up to 6000 h)

III. COMPACT FLUORESCENT LAMPS (CFLs)

Models:
* Tubes without integrated ballsts
* Retrofit tubes with integrated ballasts
* Retrofit spiral tubes
* Retrofit A-bulbs with outer envelope
* Retrofit globes & decorative with outer envelope
* Retrofit reflectorlamps

Advantages:
+ "Up to 80%" (in reality closer to 50%) more light than an incandescent
+ Long lifetime (6 000-15 000 hrs, with diminishing output)
+ Available with warm or cool light

Disadvantages:
- No bright point lighting
- Most models still have unnatural colour
- Suboptimal colour rendering (CRI 82-85)
- Naked tubes often glaring
- Relatively long starting and warm up time
- Lower Power Factor (often around 0.5)
- Sensitive to heat; poor function in closed luminaires
- Many have poor performance in cool temperatures
- May be sensitive to moisture
- May be sensitive to rapid on-off switching
- Often not dimmable (those that are often expensive)
- Dimming makes the light cooler/greyer, not warmer
- Too large for some luminaires
- Do perform well in reflector luminaires
- Some require specific burning position
- Higher production, transportation and recycling costs
- Contain small amounts of mercury (2-5 mg)
- Bare tubes may emit a little UV

IV. LIGHT EMITTING DIODES (LEDs)

Models:
* Reflector lamps (diodes stuck in a reflector lamp)
* Retrofit standard bulbs (diodes stuck on a stick and placed in a bulb).
* Decorative (tube lights etc)

Advantages:
+ Good efficacy (high output per watt)
+ Extremely long life (unless overheated)
+ Light up instantly
+ Warm, cool or coloured light
+ Versatile due to very small size
+ Not sensitive to vibrations, power spikes or rapid cycling
+ Not sensitive to cold
+ Give off less heat than other lamps, can be touched
+ Simpler to produce and recycle than CFLs
+ Contain no mercury

Disadvantages:
- Most common as low-watt lamps*
- Give light only in one direction, in narrow beam
- More or less unnatural light colour*
- Unstable colour, warm-white LEDs shift over time
- Mediocre to good colour rendering*
- Sensitive to heat
- Lower Power Factor than incandescent*
- Expensive*

* Under improvement

References:
EU consultants' Technical Briefing (italicised points)
Philips Lighting
OSRAM
Havells-Sylvania
GE Lighting
MEGAMAN
Aura Light