Lighting Myth: You should never turn off fluorescent lights.
When fluorescent lights first came into use in the 1950s, people developed the habit
of leaving the lights on. Like many myths, this one has lived well past its useful
life.
As a general rule, you should turn off the lights whenever you leave a room. It's
just a good habit to develop. Turning off the lights reduces operating costs in
two ways: it saves energy and reduces the number of lamp replacements.
But doesn't it take more energy to start up the light than it does to run the lamp
for several minutes? In a word: No. It is true that fluorescent lamps draw an inrush
current that is five times greater than the operating current. However, the initial
surge of a rapid start lamp lasts for only 1/120th of a second. So, you have to
turn the lamp off for only one second to save the same amount of energy used to
start it up again.
But, doesn't the starting cathode erode each time the lamp is started? Yes. Cathode
erosion is one factor that limits lamp life. While turning off the lights reduces
the number of hours the lamp will burn, it extends the time between lamp replacements.
For example, a standard rapid-start fluorescent lamp operating continuously will
burn for 38,000 hours or 4.3 years. If the same lamp burns only 12 hours per day,
the number of operating hours drops to 30,000. However, the lamp will remain in
service for 6.8 years. So, you cut operating energy in half and reduce lamp replacement
costs by 30 percent. It's not necessary to go through elaborate calculations each
time you leave a room. As general rule of thumb, it's always better to turn off
the light, even if you'll be gone only a minute or two. Make a habit of turning
off the lights every time you leave.
Forty years ago, leaving the lights burning continuously may have been the best
thing to do. However, a few things have changed since then. Fluorescent lamps are
more durable, energy is several times more expensive, and fluorescents are used
in more locations than ever before. If you want to save money on energy and lamp
replacement, turn it off!
One reason that some lights burn continuously is that building staff don't know
which switches to flip. For example, in a retail store, staff may arrive at 7 a.m.,
but business hours don't begin until 10 a.m. Only a portion of the lights needs
to be on before opening time. To solve this problem, EWEB provides "Switch Hitter"
stickers that identify how to operate lighting circuits. The stickers can be applied
to a service panel or wall-mounted light switches. EWEB provides Switch Hitters
free, but quantities are limited. Call Energy Management Services at (541) 685-7000 today.