Air Leaks – How exactly does your airflow?
You try to create a shelter for your family the best way you know how. Within the house drywall and thermal insulation is used that creates boundaries between conditioned space and unconditioned spaces. The problem is that these houses are full of holes. But, it turns out some holes leak more than others. Why? The First Law of Holes.
The First Law of Holes says, “The amount of air leaking through a hole depends on two things: the size of the hole and the pressure difference across (on either side of) the hole.”
No hole, no leak. Hole but no pressure difference across it, no leak. So holes that are bigger are more important (no surprise there) and holes that have a greater pressure difference on either side of them are more important. Where do we find those?
The attic floor! Because of Stack Effect, the highest area of pressure in the home is at the drywall at the top of the house, relative to the pressure in the attic. Warm air the customer paid to heat will find any gap, crack or penetration in the drywall (air boundary) and leak into the colder attic. This makes the people in the house uncomfortable. And it wastes money because the air that replaces lost air needs to be heated again.