A tight envelope may exacerbate indoor air quality problems, so what should you watch for? By Fernando Pages Ruiz Tightening a home’s building envelope can result in significant energy savings, but it can also choke off the air exchanged through the building shell, potentially contributing to the buildup of indoor air pollutants. Improving IAQ requires a systems approach…The prescriptive directions of Indoor airPLUS focus on seven general categories: moisture control, radon mitigation, pest management, HVAC best practices with whole house ventilation, proper combustion venting, specifying building materials with reduced chemical off-gassing potential, and home commissioning… a balance between proper ventilation and source control.