Is your home really dusty?

Oof. This family's home has been so dusty that their A/C filter gets occlusively dirty within a week.

Their evaporative cooler ("swamp cooler") was removed 10 years ago, but the duct was never removed, capped or sealed. The duct is venting 450 cfm of air from the house (via the 4-ton HVAC system) into the attic.

The resulting depressurization in the home was massive: -7.4 Pascal. Also, the fireplace damper has been open for about a year, so soot and ash also are being pulled into the house to make up the air that was lost to the attic through this disconnected duct.

The wife gets at least one sinus infection per year.