Some facts regarding vinyl windows from the City of Newport, Kentucky’s Historic Preservation office:

  • Vinyl is not a rigid material and will shrink and expand during the seasons. Vinyl expands more than twice that of wood. It expands seven times farther than glass with each degree of temperature. This can cause the seal between the vinyl framework and the glass to fail.
  • Wood windows have survived for centuries. Vinyl windows have a 15 to 20 year lifespan.
  • Insulated vinyl windows have desiccant filled spacers between the glass panes. The desiccant eventually absorbs all the moisture making the window appear cloudy.
  • As much as 85% of air filtration (or heat loss) is around the edges of the sash, not through the glass.

Solutions from the City of San Antonio Office of Historic Preservation Guidelines:

  • Maintain your windows, replace caulking and glazing putty, and check locks to ensure a tight seal.
  • Add interior storm windows.
  • Add UV film to windows to reduce solar gain, but OHP cautions to avoid tinted or mirrored films.
  • Attend a Window Rehab Workshop, periodically offered by the OHP.
    Insulate your attic. These areas have more “energy loss” than your windows.

Wall insulation is not recommended. In a warm, humid climate, moisture inside the walls may cause rot and decay. Moist insulation, or any wet building material, will actually increase the energy transfer through the wall. (Energy retrofits for historic homes in hot-humid climates by the Center for Cultural Sustainability at UTSA.)

- Cherise Bell

Reference