The way houses are built , especially older housing stock, have built in leakage issues. Framed houses with various siding are especially vulnerable to air infiltration- ex filtration leakage. In winter conditions, warm buoyant or lighter air rises from the home and ends up leaving the conditioned space into the attic. When the conditioned air leaves through the attic , air infiltrates from outside to equalize. So for every cubic of air that leaves through the attic an equal amount has to come in through the lower openings, cracks and voids in the home. A good evidence of this is dirty insulation in the rim joist of the basement perimeter and dirty insulation over the wall plate gaps in framing, pluming and wire holes in the attic.
What was previously described in the paragraph above is commonly termed stack effect or chimney effect. Like a chimney, the taller a home is the more stack effect pressure causes air to move from low to high holes in the home. For example, with a chimney damper , the more the damper is opened the more the chimney draws air out. Likewise the more holes a home has from bottom to top , the more air stacks or leaks out.
Leaking air out or into a home causes discomfort, static shock, drafts, hot and cold spots, dust, issues. To ensure control of your living space, energy usage, and comfort , strategic air sealing is the answer . Using a diagnostic tool called a Blower Door and a thermal imaging camera , a work scope for air sealing is produced. When sealing a home, consideration is given to combustion appliance safety. So any home sealed by PEC, protocol dictates that we measure draft of flues and combustion appliances according to BPI standards for safety before sealing and after, referred to as test in and test out.
Building Performance Institute ( BPI )
The Building Performance Institute is the nation’s premier credentialing, quality assurance and standards setting organization for home performance professionals.