Interior Storm Windows

Homeowners are usually interested in lowering energy expenses, but are not always willing to pay large costs or sacrifice the appearance of their home to do so. Interior storm windows provide a compromise by increasing the energy performance of a home at significant cost savings over window replacement. They are particularly suited to historic and other homes where it is desirable to retain the original windows or to improve efficiency without altering the homeвЂ™s exterior appearance. In addition to energy benefits, interior storm windows can improve sound resistance, decrease window condensation, and reduce degradation to furnishings from ultraviolet (UV) light.

Tight-fitting interior storm windows can reduce drafts, thereby improving comfort. By creating an airspace between the interior and exterior windows, they also improve the insulating value of the window assembly and raise the interior window temperature (hence also improving comfort in addition to reducing energy bills). One field study of interior storm windows at three Florida residences reported heating and cooling energy savings of 29 percent and noticeably reduced interior window condensation.

Interior storm windows can function in place, year-round, or can be removed from windows for ventilation during milder weather. They can also be customized to fit any size rectangular window and some manufacturers advertise the ability to fit a variety of geometric shaped windows. Interior storm windows generally have mounting brackets made of vinyl or metal that are permanently fastened to one or more sides of the interior window frame, and detachable glass or acrylic panes. The transparent pane commonly incorporates a magnetic strip for easy attachment to the bracket. Panes are also available in low-E glazing to resist heat gain and in UV-resistant glazing to reduce UV damage to interior furnishings.

Interior storm windows must be removed for natural ventilation. Interior storm windows with acrylic or polycarbonate glazing need extra care to prevent scratching or clouding. The seal around the perimeter of the interior storm window must be maintained for effective sound and thermal insulation. A magnetic seal may deteriorate over time and allow condensation to form on the interior surface of the storm window.

Interior storm windows cost less than replacement windows and reduce utility bills for the occupants.
Interior storm windows reduce drafts and improve the insulating ability of a window assembly.
By raising the interior window temperature, interior storm windows reduce the likelihood of condensation on windows, thereby reducing maintenance needs.