PATHWAY TO A MORE SUSTAINABLE PLANET - CONTINUOUS WALL INSULATION IN HOMES AND BUILDINGS
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CONTINUOUS WALL INSULATION REPORT
IN HOMES AND BUILDINGS 2020
PATHWAY
TO A MORE
SUSTAINABLE
PLANET
Eneref Institute examines how
polyisocyanurate continuous wall insulation
can help reduce carbon emissions.
TM
PR FOR PLANET EARTH
CONTINUOUS WALL INSULATION
IS AN ENERGY-SAVING HVAC Carlisle, Atlas Roofing, Firestone,
GAF, IKO, Johns Manville,
SOLUTION FOR HOMES & BUILDINGS Rmax and Soprema. With the
Polyiso CWI insulation can reduce the energy demand recently heightened interest in
of heating and cooling systems and also add structural Continuous Wall Insulation, the
integrity and moisture resistance. worldwide market for polyiso
insulation is expected to grow.
The Polyisocyanurate Insulation
Constructing energy-efficient movement of heat, air and
Manufacturers Association
high-performance homes moisture through the building
represents the group in
and buildings is necessary to envelope. Continuous Wall Washington DC, headed up by
reduce global CO2 emissions Insulation (CWI) has the benefit its President, Justin Koscher.
and mitigate climate change. of sealing all the surfaces of
As such, insulation should a home or building, including Yet, despite the commercial
be a priority. However, while the walls and roof, to prevent market gains and technological
homeowners are naturally thermal tunnels—the leaking advances of polyiso, the
well-attuned to their home’s of heat. CWI systems can be residential insulation market is
aesthetics, too often they fail installed on either the interior or still dominated by fiberglass
to invest in tighter insulation exterior surface of the building and mineral wool. The major
technologies that would greatly envelope. players in residential insulation
reduce their home’s heating and include Owens Corning,
cooling energy demand. And CWI is made of a semi-rigid CertainTeed, Johns Manville,
commercial builders are often closed-cell foam typically manu- Knauf and Rockwool.
reticent to change construction factured of polyisocyanurate,
Lower cost, complacency and
practices even when new which the industry terms “poly-
industry inertia are the primary
technologies may offer better iso.” The foam is formulated by
reasons that fiberglass and
solutions. combining two liquid chemicals:
mineral wool cavity insulation
polyol and isocyanate.
Building codes should therefore are more common than
mandate the healthiest, most polyiso in home and building
POLYISO INSULATION
energy-efficient and most construction, but the market
MARKET
structurally sound insulation strength of the major players is
Because of its rigidity, water
systems for commercial and a significant contributing factor
resistance and overall strength,
residential construction. as well. NAIMA, the organization
polyiso foam insulation is
Continuous Wall Insulation, representing traditional insulation
often used for energy-efficient
examined in this report, is a cost- companies, has also gathered
low-slope commercial roofs.
effective solution that provides years of research documenting
Today, already 75 percent of US
strong resistance to thermal air the benefits of fiberglass and
commercial roofs use polyiso
flow and moisture infiltration mineral wool.
insulation. The United States
while supplementing structural
represents the largest market However, as Eric Rexrode
integrity.
for polyiso insulation worldwide, explains, “Polyiso is definitely
Walls, of course, function to followed by Europe. The major the preferred choice for the roof,
separate the interior from US manufacturing brands of so why wouldn’t you use it to
the exterior, restricting the high-quality polyiso include insulate the rest of your building,
RESEARCH COMPILED AND PROVIDED COURTESY OF ENEREF INSTITUTE • WWW.ENEREF.ORG • COPYRIGHT© ENEREF INSTITUTE • ALL RIGHTS RESERVED
too?” Rexrode is R&D Manager of has been popularized by Owens industry collaborates on
Rigid Raw Materials at Covestro, Corning’s use of the Pink Panther developing energy codes.
a leading manufacturer of but is also sold by DuPont The competing materials
polymers to the insulation market and Kingspan. are specified for different
and polyiso manufacturers. applications but can potentially
Cavity insulation, of course, isn’t Most polyiso boards are about
provide the same thermal
going away. However, installers 2 to 2.5 inches thick, with
performance as each other,
can now take advantage of a some boards as thin as half
albeit with appropriate
trend and increase revenue by an inch. In Europe, polyiso thicknesses to accommodate
installing CWI. is made as thick as 7 inches. their differing R-values.
Typically, the polyiso used in
THE CWI SOLUTION Continuous Wall Insulation has Panelization and modular
All insulation basically performs a facer material, which acts construction may help drive
the same function: to provide as an additional barrier to air, change. One recently introduced
resistance to heat flow. While this moisture vapor and water. dual technology gaining traction
report examines polyisocyanurate Polyiso is manufactured with with homebuilders employs
foam (polyiso), a variety of a variety of facer materials for Continuous Wall Insulation
insulation materials with different different functionality, many of polyiso on the exterior of the
properties can be used to create home and spray polyurethane
which are made from recycled
Continuous Wall Insulation, foam (SPF) in the wall cavity.
components.
including expanded polystyrene Covestro LLC, a spin off of
(EPS) and extruded polystyrene While the various insulation German company Bayer, in
(XPS). Polystyrene products materials compete for market collaboration with Hunter Panels,
compete with polyiso for market share, in an effort to drive a leading polyiso manufacturer
share in the residential rigid foam demand for a strong thermal based in Portland, Maine,
market. Extruded polystyrene envelope, the insulation manufactures and markets this
INCHES OF MATERIAL NEEDED TO REACH R-15
©COPYRIGHT ENEREF INSTITUTE
SM A LLE R N UMB E R ME A N S A B E T TE R IN SU L ATO R
FIBERGL ASS
4.0
POLYISO
2.3
POLYST YRENE
3.0
SPRAY POLYURETHANE FOAM
2.3
LOOSE FILL INSUL ATION
4.0
0 0.5in 1.0in 1.5in 2.0in 2.5in 3.0in 3.5in 4.0in 4.5in 5.0in
RESEARCH COMPILED AND PROVIDED COURTESY OF ENEREF INSTITUTE • WWW.ENEREF.ORG • COPYRIGHT© ENEREF INSTITUTE • ALL RIGHTS RESERVED
panel with built-in polyiso is scheduled in the near future.
Huber Engineered Woods’ ZIP
System, which also eliminates BEST PRACTICES
the need for housewrap. Despite the potential barriers,
Eneref’s field research has
MARKET OBSTACLES shown that homebuilders are
Because polyiso Continuous increasingly adopting CWI. As
Wall Insulation is a practical more products and best practice
solution to help reduce guides become available,
global warming, it would builders are becoming more
benefit from incentive-based comfortable with a different
financing programs for both technique of fastening polyiso
residential and commercial to the studs on the exterior
construction. The obstacles to wall. That’s because the
faster adoption of polyiso CWI value proposition for polyiso
are similar to other energy- Continuous Wall Insulation is
saving technologies. While CWI compelling and persuasive.
represents the best solution in
many applications, the low cost CWI can significantly reduce
MODULAR WALL CONSTRUCTION the energy demand of home
of energy in the US increases
Recently introduced PUReWall the time needed to see a return heating and cooling systems.
combines polyiso on the exterior
on investment. Traditionally, thermal insulation
and SPF in the wall cavity.
for walls is installed in the
In residential construction, cavities between the 2x4 wall
insulation solution as PUReWall, most homebuyers don’t fully framing. However, this approach
a complete wall system for appreciate the heating and allows heat to escape—into
residential construction. Spray cooling cost savings they would or out of the home. Because
polyurethane foam (SPF) see with better insulation. the wall framing is exposed
is a spray-applied blend of Large tract homebuilders tend to changes in outside air
isocyanate and polyol resin that to eschew CWI, even though temperature, it acts as a “thermal
is more costly than fiberglass it has a high R-value per inch
bridge” for heat flow.
and cellulose but has a higher when compared to common
alternatives, because insulation Polyiso CWI creates an
R-value per inch. SPF can air-
represents a sizable percentage uninterrupted barrier that
seal buildings, cracks and gaps.
of the total construction costs for reduces thermal bridges by
The PUReWall self-contained
mid-priced homes. However, in providing a continuous layer
insulated modular wall panel is
commercial construction, polyiso of insulation over the entire
manufactured with taped joints
is already commonly specified for wall surface. This application
to create weather-resistant tight
roofing insulation and is therefore method is especially useful
tolerances, thereby eliminating
readily and locally available with wood- or steel-framed
the need for additional house
throughout the US. Today, polyiso construction, significantly
wrapping material.
is manufactured in 36 plants increasing the energy efficiency
Another all-in-one structural across North America, with more of a home. By blocking thermal
v31-2
RESEARCH COMPILED AND PROVIDED COURTESY OF ENEREF INSTITUTE • WWW.ENEREF.ORG • COPYRIGHT© ENEREF INSTITUTE • ALL RIGHTS RESERVEDbridging, Continuous Wall Lastly, although polyiso is a LIMITING GLOBAL
Insulation increases the overall petroleum-based insulation, WARMING
thermal performance of the wall the foam is required to pass To reduce the carbon emission
assembly and the home. a number of flammability of heating and cooling systems
tests. Major manufacturers in homes and buildings,
SLENDER, STRUCTURALLY custom-develop their polyiso model energy codes need to
SOUND AND DURABLE formulations to target specific emphasize higher-performing
Not only does polyiso deliver a flammability performance wall assemblies that insulate
high R-value per inch compared measures and fire standards the entire wall, like polyiso CWI,
to other types of continuous required by the building code. rather than just the wall cavity.
insulation, but it also adds
structural stability, creating a
more durable wall. Although
polyiso CWI alone is not a
structural bracing material,
laminating polyiso to structural
THE SciBox:
THE CHEMISTRY
materials increases the
dimensional integrity of the wall.
Adding CWI to cavity insulation
protects interiors and wall
OF POLYISO
cavities from condensation and
keeps moisture from entering
the house, reducing the risk of
rot and rust. When water vapor CWI is made of a semi-rigid closed-cell foam
cools, it condenses, creating
typically manufactured of polyisocyanurate.
moisture on the wall surface. CWI
keeps the inside air from seeing
that outside moisture-laden P O LY I S O C YA N U R AT E ( P O LY I S O ) I S M A N U FA C T U R E D
air by warming the studs and by mixing isocyanate and a polyol blend with a catalyst,
maintaining the wall cavity at the along with other performance-boosting additives
same temperature as the interior
including blowing agents and flame retardants. Polyiso
environment. CWI is also a
works as an insulator precisely because it is a closed-cell
secondary line of defense against
rainwater intrusion. foam: foam is primarily gas locked inside bubbles, and
gases conduct significantly less heat than solids. For
The higher R-value of polyiso
polyiso, the ratio is 30 parts gas to 1 part solid material.
CWI allows for thinner walls,
and thus more usable floor The gases used in polyiso foams are chosen based on how
area within the footprint of the little heat they conduct. To fabricate polyiso, the chemical
home or building. And some components are blended, poured between two pieces
contractors interviewed for
of facer material, and then run through a laminator in a
this report found that cladding
continuous process to form the rigid boards.
materials were more easily
installed over polyiso CWI.
RESEARCH COMPILED AND PROVIDED COURTESY OF ENEREF INSTITUTE • WWW.ENEREF.ORG • COPYRIGHT© ENEREF INSTITUTE • ALL RIGHTS RESERVEDLEAD BY EXAMPLE. ENEREF CAMPAIGNS ARE DESIGNED TO CREATE A COMMON UNDERSTANDING OF SOLUTIONS TO GLOBAL WARMING AND ENCOURAGE PEOPLE TO TAKE ACTION. A S A S O C I E T Y, we’re more likely to action. Eneref Campaigns bring about act on environmental solutions when that positive tipping point by creating knowledge is shared. That is, when every the dynamic of common knowledge member knows the same information— and the perceived social pressure to act and knows that every other member responsibly. We’ll ignite a movement so shares that knowledge, too. A viral that you can lead others. argument becomes common knowledge, Visit eneref.org. and common knowledge becomes LEAD OTHERS. INFLUENCE CAUSE. DRIVE CHANGE. eneref.org
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must harness their capacity to
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Right now, we need to make
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