Air Infltration
Controls air infiltration
One of the country’s most critical home energy problems
is air infiltration. United States Government Energy Labs
estimate that air infiltration wastes up to 40% of every
home heating and cooling dollar. Unfortunately, most residential
buildings were constructed before the size of the problem,
and the ease of the solution, were so widely known.
Spray Polyurethane Foams have been used as a high-performance
insulation material for more than 30 years. However, their
multi-functional role as insulating air- and vapor-retarders
has increased in new and retrofit construction markets.
Investigations by building scientists have shown air leakage
to be the main problem responsible for poor energy conservation
performance in buildings.
People call it “air infiltration” but, technically,
its unwanted, uncontrolled airflow through the house, moving
in or out of the structure. For example, in cold weather,
the heated air inside the house flows out. Frigid outside
air and moisture leak in – rooms feel drafty.
This uncontrolled air disrupts the temperature, air pressure
and humidity of the living space, in any weather. The heating
and cooling system has to work harder to maintain your family’s
comfort. Energy is wasted and that causes higher utility
bills.
Air infiltration is caused by leaks around windows and
doors, and by the spaces, joints, voids and cracks hidden
inside the structure. Hidden is the problem. Once the house
is finished, gaps become invisible but they are there. Air
penetrates the building shell in one location, flows through
interior cavities and emerges at a different location. Typically,
this uncontrolled air travels through the house inside walls
and ceilings, under baseboards, and along hidden pathways
in the plumbing and electrical system. Even the best-built
houses have seams and gaps that permit air infiltration.
Unlike other home insulations, the sealing quality of SPF
eliminates the need for wind-inhibiting building wraps,
tapes and caulking and, depending on the type of design
construction, even sheathing can be eliminated.
SPF has many advantages that the designer can exploit
when specifying an air barrier for the building envelope.
Its inherent fully adhered and structural nature lends itself
to fulfilling the requirements of an air barrier.
- A home that is well-insulated and protected from moisture
intrusion through effective air infiltration control...
- reduces the usage of fossil fuels for energy
- reduces the CO2 emissions that are damaging the
environment, AND
- saves the homeowner money.
The
U.S. Department of Commerce brochure NISTIR 4821,
Envelope Design Guidelines for Federal Office Buildings:
Thermal Integrity and Airtightness, which was prepared
as a guideline for the General Services Administration,
recognizes and states that...
spray polyurethane foam alone
“CAN provide an
air- and water-tight barrier." |
Reduces/eliminates Convection Currents Within
The Walls
Intrusion of air into the stud wall cavity causes convection
(movement of warm air to the top of the cavity and cold
to the bottom). After the insulation is installed, there
should not be any air circulation from one side of the stud
space to the other. Any cracks or breaks in the system will
reduce the effectiveness of the insulation. Unlike other
insulations such as fiber, which permit air movement, SPF
stops air infiltration and reduces convection.
Minimizes Infestation
SPF has no nutritional value that would attract insects
or other pests.
Minimizes Thermal Bridging
Different components of building construction have differing
thermal resistances factors. This can produce cold areas
that lead to condensation inside the walls. SPF covers the
bridges on all sides, greatly reducing the transmission
of heat or cold. Fully-adhered SPF replaces the need for
adhesives or numerous mechanical fasteners that penetrate
the substrate and decrease insulation efficiency.
Controls Condensation
Many homes now are built tighter and with greater insulation
than ever before. However, this can mean that moisture from
cooking, laundry and showers can be trapped in attics and
other places where it can lead to wood rot, peeling paint,
and deteriorating roofing and ceiling materials. In turn,
that can affect the insulation value of commonly used home
insulation materials. Used to insulate, SPF insulation systems
control both heat build-up and condensation, resulting in
a cooler attic in warmer environments and a dryer attic
in cold climates. For the homeowner, that means comfort,
energy conservation and structural stability.
Sprayed-in-place polyurethane foam insulation
adheres to, conforms to, and fills in all the little nooks
and crannies in your home's walls, floors, and ceilings
and forms a tight insulating barrier that stops air leakage.
The result is that your home is more comfortable and costs
less to heat and cool.
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