ENERGY STAR
estimates that if efficient lighting were used throughout the country
in all locations where it has been shown to be profitable, the nation's
annual demand for electricity would be cut by more than 10%, saving
ratepayers nearly $17 billion in utility bills and reducing as much
pollution as taking 15 million cars off the road.
In addition to the energy saved by using fewer
or more efficient lights, there are also important secondary effects
from lighting — chiefly that the electricity used for lighting
primarily turns to heat. Due to the heat generated by internal sources
such as lights, people, and equipment, most commercial buildings
in the United States require some cooling — even in the winter.
The additional air-conditioning load created by offsetting the heat
from electric lighting can add another 20% to the electricity use
attributable to lighting. The Rocky Mountain Institute estimates
that, in some cases, as much as 40% of the air conditioning load
for some buildings in summer months is simply used to cool the heat
produced by inefficient lighting.
Additionally, the majority of commercial lights
used and the associated added cooling loads often occur during periods
of peak electrical demand, therefore increasing the need for additional
generation and distribution systems.
If every U.S. household changed the lighting in
one room of their home to ENERGY STAR we would save 800 billion
kilowatt-hours of energy and keep one trillion pounds of greenhouse
gases out of the air. National annual energy savings would be equivalent
to the annual output of more than 20 large power plants. Our annual
energy savings could power more than 4 million U.S. homes for one
year.
Business and Market Opportunities
Every building needs lighting. While the cost-saving
benefits of energy-efficient lighting are clear, the initial costs
and longer payback times (2 - 4 years) may discourage some people.
When life-cycle accounting is used and the potential gains in productivity
are considered, however, market opportunities will continue to expand
significantly.
Using effective day lighting has benefits beyond saving energy.
At Wal-Mart, improved sales in areas lit by skylights were noted —
no matter what merchandise was placed in the day-lit area. Wal-Mart
never published any statistics on this phenomenon, but within
the past year Wal-Mart management decided to build all its new
stores with more natural light. Studies also indicate that well-designed
day lighting is associated with enhanced student performance,
as evidenced by 13 to 26% higher scores on standardized tests.
In commercial settings, a typical office worker
requires about 100 square feet (ft2) of dedicated space. Standard
lighting systems consume energy at an average rate of 1.2 watts
/ ft2 and the annualised cost of owning ($30/yr) and operating
($35/yr) a lighting system is approximately $65 per employee per
year. Top of the line lighting systems with dimming controls and
energy-efficient equipment cost $250-$500 per worker, or roughly
the equivalent of a good office chair. Any improvement to an ordinary
lighting system that improves productivity is very quickly repaid.
For example, if the direct cost of the employee is $50,000/yr,
(wages, taxes, benefits, and overhead) and the employee has an
assumed productivity ratio of 1:1, (i.e., the employee produces
$1 of revenue per $1 of cost), a 1% increase in productivity throughout
the year would realize a benefit of $500—a 100% return on
investment. In reality, employee benefit ratios significantly
exceed 1:1, so the actual return on increased productivity should
be even greater than in this example.
What Does it Cost?
As noted above, the cost of lighting is relatively
small when compared to potential productivity gains. |
