Air leakage or air infiltration is measured in A.C.H. or Air Changes per Hour. This is how many times the outside air is recirculated with your heated or cooled inside air. In a typical fiberglass home, there will be about 4.5 – 6 A.C.H, while in a AIRLOCK Insulation insulated home it is 1.5 to 2 A.C.H. that is at least 2+ times per hour that you will have to heat your home every hour if you have a fiberglass home.
When the wind hits your home, it forces its way in through the gaps and cracks in your walls, windows, doors, and basement rim joist (the top of the exterior wall in your basement). This air infiltration causes a pressurization in the home. And because the heat rises, the heated air is then forced through all the air penetration points in the ceiling, i.e. the wires, plumbing, HVAC, and any gaps, cracks, or openings in the attic floor.
Many times, the attic floor is covered with existing blown or fiberglass batts which inhibit the ability to do an air seal. The worst thing to do is to cover this with more insulation because the pressurization will force the air through the ceiling penetrations and that will pass laterally and leak out of the home. This is a common mistake. We recommend to never put good insulation on top of bad insulation.
If only the attic is done properly, this can greatly increase the performance of the home. We recommend doing the attic (at least) if the walls cannot be done simultaneously.
The attic is equivalent to 60% of the energy efficiency, The walls are about 30%, and the basement rim joist is about 10%. In doing all three with cellulose, your home can increase energy saving up to 40%