Ace Building Inspectors
We do our inspections right the first time…everytime

Indoor Air Quality


There are many sources of indoor air pollution in any home. These include combustion sources such as oil, gas, kerosene, coal, wood, and tobacco products; building materials and furnishings as diverse as deteriorated, asbestos-containing insulation, wet or damp carpet, and cabinetry or furniture made of certain pressed wood products; products for household cleaning and maintenance, personal care, or hobbies; central heating and cooling systems and humidification devices; and outdoor sources such as radon, pesticides, and outdoor air pollution.

A proper air exchange rate is vital for maintaining healthy indoor air. Homes on night cooling shall have 10-18 effective air exchanges (the rate at which outdoor air replaces indoor air) per hour. Air exchange rate is managed through natural (windows or walls) and/or mechanical ventilation.

Exhaust ventilation systems work by depressurizing the building. By reducing the inside air pressure below the outdoor air pressure, they extract indoor air from a house while make-up air infiltrates through leaks in the building shell and through intentional, passive vents. Adjustable, passive vents through windows or walls can be installed in other rooms to introduce fresh air to balance the negative indoor pressure against outdoor air pressure. Negative air pressure inside of the house can cause back drafting of combustion appliances (carbon monoxide); mold, mildew and moisture as well as condensation; lack of fresh air, a musty smell, lingering odors around the house; stagnant, stale, heavy, air causing high humidity and condensation; and rush of air or draft when opening an exterior door.