What is the Big Deal About Air Infiltration Any Way?
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. |
