For any given hole, the amount of air moving through will be a function of the characteristics of the hole and pressures. And remember, if we stop the air from leaving our home, we will automatically reduce the air we feel entering our home. Forced air heating systems use pressure to move air across a heat exchanger, and into our conditioned spaces. The same system creates pressure across a furnace filter drawing air through the filter, which in turn catches the particles in the air. If the forced air system were not operating, a home would not have any filtration no matter how efficient the filter.
Heat moves from areas of higher temperature to areas of lower temperature.
When heating, your home's warm air is escaping to the outside, and while cooling the opposite is happening. To understand how we slow heat movement in our homes, we need to discuss the mechanisms of heat flow. There are basically three types of heat flow we need to be concerned with. These same holes and pressures can move substantial amounts of moisture through the insulation. If we try to move moist air through insulation, the dewpoint and the resulting condensation can occur in closed wall or ceiling systems.