 The
Real Cost of Lighting
Over the life of a typical light fixture the greatest expense incurred
by far is the electricity it consumes, not the cost of lamp replacement
or even the initial cost of the fixture. The incremental cost of adding
energy efficient lighting to new construction can be re-couped in as little
as 60 days or 1 year in the case of a retrofit of an existing building.
Another common misconception is that lighting doesn't consume as much
electricity as air conditioning. In the home this may be true since lighting
typically d oesn't
operate during the day. But in commercial facilities the lights operate
during working hours, and depending upon climate conditions and the type
of facility, lighting and its resulting heat load can account for as much
as 40% of the total bill.
Reduction in Fixture
Input Wattage
The input wattage of a standard magnetic ballast and two 40 watt T-12
lamps is 96 watts, whereas the input wattage of a low power electronic
ballast and two T-8 lamps is 49 watts, almost a 50% reduction. Even more
savings can be realized by delamping (removing lamps) while maintaining
comparable light levels using a high output ballast, the stronger and
higher color rendering lamps, a reflector or all of the above. LED exit
signs use less than 10% of the energy consumed by incandescent exit signs,
and compact fluorescent lamps (CFL) use less than 25% of the energy consumed
by incandescent bulbs. Light levels can be maintained and are in some
cases better than before the fixture retrofit or replacement.
Air Conditioning
Savings
Lighting is a very inefficient and mostly unwanted source of heat. This
heat is useful during the winter, but during the summer it causes the
air conditioning system to work harder. Depending upon the climate this
"heat load factor" can range from .90 in cold climates to 1.31 in hot
climates.
Lower Maintenance
Cost
Electronic ballasts, T-8's, CFL's, and LED's last longer than magnetic
ballasts, T-12's and incandescents. After delamping, there are fewer lamps
to replace, and considering that the labor cost of replacing lighting
is typically greater than the cost of the component itself, the total
savings can be very significant.
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