Energy-conservation corner

Does turning lights on and off throughout the day really
conserve energy and save money?

As a follow-up to the light-switch sticker effort, O&M
reviewed a research study on lamp life conducted by the
Electric Power Research Institute. Four-foot fluorescent
light tubes will last 27,000 hours if their burn time equals
nine or 10 hours a day. Turning these lights on and off
throughout the day will shorten the lamp life, but the
energy cost avoidance exceeds the cost of shortened lamp
life.

One fluorescent lamp, cycled one hour on and 30 minutes off
throughout a 10-hour workday, would yield a cost avoidance
of $1.38 annually. Even with increased replacement costs,
the net cost-avoidance would still be $1.05 per four-foot
lamp. Since there are about 500,000 fluorescent lamps on
campus, the total cost-avoidance could amount to more than
$500,000 based on the above scenario.

Of course, conserving energy does not take precedence over
safety. If lights need to remain on for safety or security
reasons, users should act accordingly. In most cases,
however, the message on the light switch stickers still
applies ...

"Not in use? Turn off the juice."


The "Energy Conservation Corner" will be published every
other month. Questions about energy-conservation programs or
practices should be directed to Jeff Buenting at 333-1364 or
jdbuenti@illinois.edu.