Window Background Ventilation: The Planned Leak Airtight Homes Need
Window Background Ventilation Is a Designed Leak, Not a Defect The best window retrofit is not the one that eliminates every hint of airflow. It is the one that replaces random leakage with a deliberate, predictable path for fresh air. That distinction matters because many condensation and indoor air complaints begin right after a home gets better windows. The old sashes rattled. The weatherstripping was tired. The meeting rails leaked in winter. Heating bills were higher than they should have been, but the house had one accidental advantage: outdoor air was constantly finding its way in. When tight double- or triple-glazed units replace those old windows, the heat loss drops, but so does the background ventilation that had been masking moisture, carbon dioxide, cleaning-product fumes, and odors. ...