Exterior Window Shades & Shutters
Exterior Roller & Hinged Shutters
Often referred to as “interior storm windows,” interior glazing panels are an inexpensive way to add a layer of glazing to a window to boost energy performance. They function much like exterior storm windows, except that they don’t provide additional protection against the elements. Most are designed to be removed in the summer, though some include operable panels on tracks.
Most interior glazing panels are lightweight with plastic glazing or clear plastic film. The most common glazings are acrylic (such as Plexiglas) or polycarbonate (such as Lexan). Polycarbonate is stronger than acrylic, but softer, so more scratch-prone. Acrylic now contains ultraviolet light inhibitors that slow yellowing. Glass is sometimes used and is the most durable, as long as it doesn’t get broken, but is also heavier. With glass, including a low-e coating may be possible, which will boost energy performance significantly (unfortunately, low-e often isn’t an option).
The frames are most commonly aluminum, but can be vinyl, wood, or steel. Steel frames may come with rubber-encased magnetic weatherstripping, for a tight seal to window frames or metallic strips added to the window casings. At least one manufacturer of interior glazing panels produces a double-glazed panel with thin plastic film stretched taught around a tubular aluminum frame. Do-it-yourself kits are available with frames and heat-shrink plastic film that is stretched taut over frames using a hair dryer.
For moisture management, it is preferable to have the inner layer of glazing be the most airtight, since this allows trapped moisture in the window system to escape. This is a benefit of tightly fitting interior glazing panels when the prime windows are old and leaky.