Even if you live in an air quality paradise, it’s not ideal for your indoor air to be the air that manages to sneak through all the little cracks in your structure. Especially if you have cold outdoor temperatures, indoor humidity such that the outdoor temperatures are below the indoor dew point, and airflow through the walls that can lead to condensation and possibly mold in those walls.

Your indoor air should enter through windows or intentional intakes, not incidental gaps.

> Even if you live in an air quality paradise, it’s not ideal for your indoor air to be the air that manages to sneak through all the little cracks in your structure.

Small cracks are also things that critters may be able to get through.