In order to choose the best lighting for a particular
application, you need to consider qualities besides energy efficiency. Where several
lighting types work equally well, you can make your decision based on initial
cost, lamp life and efficiency.
Incandescent Lights
The old standby has many advantages. They're cheap, versatile, easy to focus,
have no strobe effect, and require neither ballasts nor warm-up periods. On
the other hand, incandescents are inefficient, short-lived, vulnerable to voltage
fluctuations and add to HVAC load.
Fluorescents
They offer true color rendition, evenly distributed illumination, no warm-up,
good efficiency and long life.
Tungsten, Halogen or Quartz Lamps
They look like conventional incandescents, but special filaments give them relatively
better efficiency and longer life.
High Pressure Sodium Vapor
They are an excellent choice for street lighting, industrial applications, outdoor
or (occasionally) indoor commercial lighting. Sodium is very efficient and long
lasting. These lamps require a ballast and a warm-up period.
Metal Halide
A source of versatile and efficient lighting, they have a cool white color range.
Lamps require a ballast, and some require a two to five-minute warm-up, and
a 10-minute cutoff between illuminations.
Mercury Vapor
They are a source of bluish white color with relatively long life. They are
less efficient than sodium or metal halide. For this reason, they are being
replaced in most applications by metal halide.
