EGEE 102
Energy Conservation for Environmental Protection

Comparison of Different Bulbs

Incandescent bulb

Incandescent Bulbs:

  • do not require a ballast
  • have a warm color appearance with a low color temperature and excellent color rendering (CRI 100)
  • are a compact light source
  • require simple maintenance due to screw-in Edison base
  • are a less efficacious light source
  • have a shorter service life than other light sources in most cases
  • have a filament that is sensitive to vibrations and jarring
  • can get very hot during operation
  • must be properly shielded because incandescent lamps can produce direct glare as a point source
  • require proper line voltage, as line voltage variations can severely affect light output and service life
Fluorescent Bulb

Fluorescent Bulbs:

  • require a ballast
  • have a range of color temperatures and color rendering capabilities
  • have low surface brightness compared to point sources
  • have a cooler operation
  • are more efficacious compared to incandescent
  • ambient temperatures and convection currents can affect light output and life
  • all fixtures installed indoors must use a Class P ballast that disconnects the ballast in the event it begins to overheat; high ballast operating temperatures can shorten ballast life
  • have options for starting methods and lamp current loadings
  • require compatibility with ballast
  • low temperatures can affect starting unless a "cold weather" ballast is specified
High Intensity Discharge (HID)bulb

High Intensity Discharge (HID) Bulbs:

  • require a ballast
  • ambient temperature does not affect light output, although low ambient temperatures can affect starting, requiring a special ballast
  • are a compact light source
  • are high lumen packages
  • are a point light source
  • have a range of color temperatures and color rendering abilities depending on the lamp type
  • have a long service life
  • are highly efficacious in many cases
  • have line voltage variations, possible line voltage drops, and circuits sized for high starting current requirements which must be considered