W H I T E PA P E R
Understanding Energy Codes
and Realizing Energy Savings
September 2, 2014
Written By: James M. Del Monaco, P.E.
Sustainability Director
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Understanding Energy Codes and Realizing Energy Savings
According to the DOE, in 2010 the primary energy consumption of the United
States was nearly 19% of the world’s total primary energy use. Of that energy
use, approximately 39% is from commercial and residential buildings. As such,
the further development of energy codes provides an opportunity to greatly
reduce the energy use not only in this country, but also the world.
In response to the energy and economic crisis
of the early 1970s, the United States began
the development of building energy codes
and standards for commercial and residential
buildings. The first standard was developed
by the American Society for Heating
Refrigeration & Air Conditioning Engineers
(ASHRAE) in 1975 and was titled ASHRAE
Standard 90-75 “Energy Conservation in
Buildings.” Also in 1975, Congress passed the
Energy Policy and Conservation Act, which
first recommended that 90-75 be adopted
as a uniform national standard. A second
national energy standard, MCEC 1977, was
developed by the Council of American
Building Officials (CABO) in 1977 and soon
became the Model Energy Code 1983. CABO
released updated versions until 1998 when the
International Code Council (ICC) developed
the International Energy Conservation Code.
(IECC). Both ASHRAE and the ICC continue
to develop these standards and codes on a
continuous maintenance program to address
the latest trends and development in energy
conservation.
The next major development of energy codes
in the United States came about from the
adoption of The Energy Policy Act of 1992.
It required that the Department of Energy
(DOE) become actively involved in the
process of developing and implementing the
latest energy codes and standards. One of the
DOE’s responsibilities included determining
© Copyright P2S Engineering, Inc whether the latest energy standards actually
save energy. The DOE informs the states if
the new versions save energy and requires
that they implement the latest approved
standard or an equivalent standard. In the
United States, the adoption and enforcement
of such standards is left up to the state and
local jurisdictions. Some states, such as
California, can choose to develop their own
energy codes. California has developed its
own energy standard, which is adopted as the
California Energy Code (CEC), Title-24 Part 6.
Energy codes today
Today’s energy codes address energy use
and efficiency of both commercial and
residential buildings. Typical components
addressed include the building envelope
(walls, roof, glazing, etc.), mechanical
systems, service water heating, indoor and
outdoor lighting, etc. The codes address such
things as minimum efficiency of equipment/
components and control features, among
others. The codes also distinguish various
requirements based on climate zone. For
example, under the 2010 CEC, a building near
Lake Tahoe would be required to provide
higher performance glazing than the same
project near Long Beach, which has a milder
climate.
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Understanding Energy Codes and Realizing Energy Savings
According to the DOE, in 2010 the primary
energy consumption of the United States was
nearly 19% of the world’s total primary energy
use. Of that energy use, approximately 39%
is from commercial and residential buildings.
As such, the further development of energy
codes provides an opportunity to greatly
reduce the energy use not only in this country,
but also the world.
But do energy codes really save
energy?
minimum building for the 2006, 2009, and
2012 IECCs as well as the 2004, 2007, and
2010 ASHRAE 90.1 standards to understand
the energy use and energy cost for each of
these prototype buildings. The study analyzed
various building types in multiple climate
zones throughout the United States utilizing
energy modeling software. Figure 1 provides
a quick overview of the findings of the study
which show that the newer energy codes are
more stringent than previous versions and do
result in energy savings.
A study published in August 2013 by the
Pacific Northwest National Laboratory (PNNL)
in conjunction with the DOE, analyzed a code
Figure 1: National Average Energy Use Intensity for all IECC Prototypes
Source: www.energycodes.gov
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Understanding Energy Codes and Realizing Energy Savings
Figure 2: Site Energy Savings for the IECC and corresponding Standard 90.1
Source: www.energycodes.gov
Overall, the 2012 IECC prototypes saved
18.6% on energy use intensity (EUI in kbtu/
sf/yr) and 17.4% on energy cost index (ECI
in $/sf/yr) when compared to the 2006
IECC prototypes. The study also analyzed
the EUI and ECI comparison between
IECC prototypes and similar ASHRAE 90.1
prototypes. Figure 2 above shows that in the
last three editions of the respective standards,
they have been on par with each other, with
the exception of the 2010 ASHRAE 90.1
which sees a 7.4% increase in efficiency when
compared to the 2012 IECC.
Looking ahead
Energy codes will continue to be reviewed
and updated to keep up with the latest
developments to improve the functionality
of buildings and increase energy efficiency.
© Copyright P2S Engineering, Inc ASHRAE recently created Standard 189.1
“Standard for the Design of High Performance,
Green Buildings.” This standard not only
continues to push the boundary of efficiency
and controls, but it also focuses on areas that
promote the functionality of the building and
its occupants. In addition to energy use, this
standard addresses such items as acoustics
and water efficiency, taking on a more holistic
approach to high performance buildings.
Similarly, California created the California
Green Building Code (CALGreen) which
addresses similar topics in conjunction with
the CEC. As these new codes are developed,
the technologies and methodology we utilize
in our design and construction will evolve to
meet the needs of the codes.
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P2S Engineering, Inc. is a full-service mechanical, electrical, plumbing, technology,
commissioning and energy engineering firm that is committed to sustainability.
We provide services that cater towards a unique point of view—the client’s.
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