LEED credits or points for going beyond the minimum energy performance
and increasing energy efficiency beyond the minimum requirement. Buildings
can receive 1 to 19 points for increasing energy performance beyond the pre-
requisite energy performance. Typically, a building simulation using the
“energy-cost budget method” is used to demonstrate energy performance
and points are earned based on percentage improvement above the baseline.
One of the potential strategies to obtain credits and points is to design
the building systems and building envelope to maximize energy performance.
This focus is obviously on HVAC, interior lighting systems and service water
heating for domestic or space heating purposes (referred to as regulated or
nonprocess systems), all of which fall under the umbrella of a smart building.
Other systems, including plug loads, are referred to as unregulated or
“process” systems. Plug loads comprise everything that plugs into the electrical
distribution system, such as PCs, displays, cameras, vending machines and
copiers. Plug loads make up 9 to 25% of a typical building’s electrical load
depending on the building type and density of devices.
An IP network is able to provide power-over-Ethernet (POE) to a range of
“plug-load” devices. POE not only supplies low-voltage rather than high-volt-
age power to these devices, but more importantly, provides the means to con-
trol power to the device. Central control of the POE devices allows for devices
to be turned on or off based on a predetermined schedule, a sensor, or an
event, such as occupant use of an access card. The result can be reduced con-
sumption of power to devices, lower power usage and a greener building.
In addition, POE reduces the use of materials, thus eliminating the need to
provide a power cable to the device.
The default process energy cost is 25% of the total energy cost for the
baseline building. If the building’s process energy cost is less than 25% of
the baseline building energy cost, the LEED submittal must include documen-
tation substantiating that process energy inputs are appropriate. For the pur-
pose of this analysis, process energy is considered to include, but is not
limited to, office and general miscellaneous equipment, computers, elevators
and escalators, kitchen cooking and refrigeration, laundry washing and drying,
lighting exempt from the lighting power allowance (e.g., lighting integral to
medical equipment), and other devices.
Process loads must be identical for both the baseline building performance
rating and the proposed building performance rating, although project teams
submit an “exceptional calculation method” (ANSI/ASHRAE/IESNA
Standard 90.1-2007 G2.5) to document measures that reduce process loads.
This documentation requires a list of the assumptions made for both the base
and the proposed design and information supporting these assumptions.
Energy and Sustainability 197