SIP Energy Tests
SIP (Structural Insulated Panels) The Preferred Building
System by Quality Builders, Developers and Home Owners
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OAK
RIDGE
SIPs Outperform Stick & Batt
in Oak Ridge National Labs R-Value Test
When someone says “R-value”,
what they’re
really talking about is resistance to heat flow in
a given medium, such as fiberglass insulation. The
higher the number,
the greater the resistance. So when a builder is asked “What’s
the R-value of this wall?”, the natural inclination
is to think of the material that most commonly specifies
its rating. More often than not, it’s the insulation,
and the response is something along the lines of “Oh,
that wall has an R-value of 19” - fairly impressive,
but also strikingly inaccurate. It’s not that
the builder is intentionally misleading his client
or associate,
but that he’s just following common practice.
In reality, this reasoning doesn’t take into
account all the other components that go into making
a wall: wood
or steel studs every 16" or 24", bracing,
nails or screws, wiring and switch boxes - any number
of things
that are not insulation, and in all likelihood, have
R-values that fall well short of the stated R-19.
A
new study by the Oak Ridge National Labs (ORNL) proves
that a 4-inch SIP wall outperforms 2"x4" stick
and batt construction, and even edges out 2"x
6" construction
in terms of thermal performance. Because SIPs are
the structural elements, there are no studs or braces
to
cause breaks
in the insulative action. The end result is a more
comfortable, energy efficient structure that performs
up to spec in
real-world conditions. Unlike stick and batt construction,
which can be subject to poorly installed - even missing
- insulation, the nature of SIPs is such that the
structural and insulative elements are joined as
one. There are
no hidden gaps, because a solid layer of foam insulation
is
integral to panel construction.
By contrast, state-of-the-art
technical analysis of whole wall performance indicates
that the losses
in
a stud
wall are much greater than you might think: on
average, the
other standard components in stick and batt construction
can reduce R-values in as much as 30% of the wall
area. Fortunately, that’s not the case with
structural insulated panels. The ORNL study found
that SIPs perform
at approximately 97% of their stated R-value overall,
losing only 3% to nail holes, seams, splines, and
the like. Wiring
chases are precut or preformed into the foam core,
providing a continuous layer of insulation keeping
the elements
at bay and the interior free of drafts and cold
spots.
A SIP wall also outperforms stick
and batt when it comes to maintaining consistent interior
temperatures,
and
that translates to improved occupant comfort.
The
interior surface
temperature of frame construction drops precipitously
at every stud, while the SIP wall remains consistent
across
its entire surface. No temperature dips mean
improved occupant comfort, regardless of where you
are in
the room. That’s
a big part of what people are talking about when
they say they can immediately “feel the difference” in
a SIP-built residential or commercial space. With
SIPs, thermal efficiency and comfort are built
in at the factory,
and now the lab results prove it.
US Department of Energy
Definitive Accredited Testing proves that SIP Systems
out perform conventional frame constructions by at
least 66%!
The
structural insulated panel industry is hailing a new
US Department of Energy study for confirming the
insulating superiority of their product.
A recent study
at DOE’s Oak Ridge National Laboratory
used a new procedure for determining a building wall’s
insulation performance. It compared 18 different wall
systems, including conventional 2X4 and 2X6 framing with
fiberglass and similar fibrous insulations and Structural
Insulated Panels (SIP’s).
SIP’s consist of
a core of rigid foam insulation in one of several forms
sandwiched between a variety
of surfaces. These surfaces are usually plywood, oriented
strand board, or metal, and finished panel replaces conventional
studwall framing in most cases.
The DOE study is said
to provide a “whole-wall
R-Value” by calculating how well heat flows through
various wall materials and how well the walls connect
to other walls, the roof, floor, doors and windows. It
was conducted by Jeffrey Christian, Director of DOE’s
Buildings Technology Center of Excellence at Oak Ridge
Laboratory, and Jan Kosny, a research engineer at the
University of Tennessee.
Net Zero Energy Research Homes Built With
SIPs
Habitat For Humanity Homes are First Of Their Kind
GIG HARBOR, Washington-Remarkable new homes
being built by Habitat for Humanity in Loudon County,
Tennessee are
projected to break new records showcasing state-of-the-art
energy efficiency. The high “whole wall R-value” and
nearly airtight construction relies on structural insulated
panels to give the houses their unprecedented performance,
shattering existing concepts of how energy-efficient
homes should be built. The goal for these net-zero-energy
dwellings is to be so energy efficient that on an annual
basis, the energy usage will not exceed what is produced
on site.
Research at ORNL has shown that in terms
of real performance a SIP wall rated at R-15, with a
3-1/2
inch EPS core, actually out-performs a fiberglass insulated
wall six inches thick and rated on paper at R-19. “The
comparison shows that a SIP wall system is thermally
very well designed,” states Jeff Christian, Director
of the Buildings Technology Center at ORNL. “The
superior design of SIPs demonstrated under identical
laboratory conditions at ORNL shows that SIPs can be
95% more airtight than wood-frame construction.” Real
time comparison of energy performance shows that the
SIP zero energy house uses 1/10 the heating energy than
a similar sized wood-framed house across the street.
These
new Habitat homes, as part of the Department of Energy’s
(DOE) Building America and Zero Energy Building programs,
are the first structures ever to combine
a number of new energy-efficient design concepts and
are the first attempts to attain zero energy on affordable
houses in the United States. In fact, the homes could
be used by the DOE as a concept model for constructing
a similar Zero Energy Building Habitat House in each
state of the country. Much like the work on the “Freedom
Car” (hydrogen fueled) under the transportation
sector, building zero energy buildings (ZEB) is the “grand
challenge” for the buildings sector.
The cost of
heating the first zero energy Habitat home, built in
the fall of 2002, was 50 cents a day during a colder
than normal winter in East Tennessee. Forty sensors were
installed in the home to monitor the thermal performance.
The second and third homes are being designed
and assembled in July 2003 by volunteers through a partnership
between
the Department of Energy Building America Program, Tennessee
Valley Authority (TVA), Oak Ridge National Laboratory
(ORNL), Habitat for Humanity, SIPA and a number of other
building industry sponsors to include Andersen Windows,
NOVA Chemicals, Rohm and Haas, Ashland Specialty Chemical,
Design Basics, FischerSlPs, Inc., Insulspan, Inc., Weyerhaeuser,
Falcon Foam, Archbold Container Corp., the Metal Roofing
Alliance and IBACOS, a Building America team.
The first
Habitat home was built using Pacemaker Plastics 4-inch
walls with 1lb. density expanded polystyrene (EPS) foam
cores. Insulspan, Inc., using 6-inch walls with 1lb.
density EPS foam, will manufacture the second house.
FischerSIPs, Inc. will manufacture the third home with
21b, density EPS foam provided by Falcon Foam. The resin
to make the foam for both houses will be donated by NOVA
Chemicals, and Weyerhaeuser will be providing all of
the OSB. Oak Ridge National Laboratory will instrument
and monitor each home and provide a report of the energy
performance. Research results incorporated by ORNL scientists
in the Zero Energy homes include a 2kW solar PV system
on the roof. TVA is offering the homeowners through the
Lenoir City Utilities Board $0.15/kWh for all the AC
solar power generated. The buy back offer is 2.4 times
the retail rate for electricity. As a result, new homeowners
may soon experience the unusual pleasure of getting a
check in the mail for power generated by the system.
Data gathered from these houses will be
used to design Zero Energy homes in other locations around
the world
in the near future. Currently, discussions are underway
at Oak Ridge National Laboratory (ORNL) to build one
home in Azerbaijan and one in Barbados. Jeff Christian,
Director of the Buildings Technology Center at ORNL,
states, “We hope to learn as we build these houses
to ultimately reach the Department of Energy’s
goal of affordable zero energy housing by the year 2015.”
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