Green Building and LEED Core Concepts Guide First Edition

ENERGY EFFICIENCY
Efforts to reduce energy demand provide the foundation for efforts to use
energy efficiently. This means getting the most productive work from a unit of energy-often
described as a measure of energy intensity. Common metries for buildings and neighborhoods include
energy use per square foot and use per capita.
Buildings need to provide efficient space conditioning, water heating, lighting, refrigeration, conveyance
(elevators and escalators), and safety (see the energy end-use profile developed by the EPA
for a typical office building, represented
in Figure 8). Green building
• 1 % - Refrigeration
. l% - Cooking
• 2% - Water Heating
5% - Ventilation
6% - Other
. 17% - L,gh tl ng
• 20% - Office Equipment
• 23% - Cooling
• 25% - Space Heating
emphasizes an integrated approach
to addressing these issues through
whole-building deSign.
For example, green building project
teams can identify opportunities to
improve building envelopes (windows,
walls, and roof) in ways thar
enable them to reduce or even eliminate
HVAC systems. This kind of
Figure 8. Energy End Uses in Typical Office Building (Source: Data from U.S. EPA Green
BUilding Workong Group)
integrated design can reduce both
initial capital COSts and long-term
operating costs.
Strategies for achieving energy efficiency include the following,
• tdentify passive design opportunities, Use the natural resources of sun and wind to heat, cool,
and,llluminate a building without add itional energy. Proper building orientation, selection of
materials, and location of windows can al low a building to be warm in the winter. stay cool in
the summer, and capture daylight.
• Address the envelope. Use the regionally appropriate amount of insulation in the walls and
roof and install high-performance glazing to minimize unwanted heat gain or toss. Make sure
that the building is properly weatherized.
• Install high-performance mechanical systems. Apply life-cyete analysis to the tradeoffs
between capital and operating costs, and evaluate investments in energy efficiency
technologies accordingly.
• Specify high-efficiency appliances. Computers, monitors, printers, and microwave ovens
that meet or exceed ENERGY STAR requirements will reduce plug load demands (that is,
electrical loads associated with plug-in appliances).
• Use high-efficiency infrastructure. Efficient street lighting and LED·based traffic signals will
reduce energy demands from neighborhood infrastructure.
• Capture efficiencies of scale. Design district heating and cooling systems, in which multiple
buildings are part of a single loop.
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Green Building and LEED Core Concepts Guide