Window design (and performance) has come a long way from the days of old. However, modern windows are still being influenced by their historic past. Classically, windows of the 19th century were adorned with window grids or window muntin since large panes of glass were more expensive to produce. The smaller panes of glass were separated by a muntin, or a bar, normally comprised of wood or metal. These bars would hold the panes of glass in place within the window. These became so common for economic reasons, that it began a trend seen well beyond the time and economic necessity.
Today, the size of glass is not hindered by economic restraints of production. Our modern version of window grids is now used as architectural interest and detail. They are no longer true window grids or window muntin but instead, simulated divided lites (SDL). A simulated divided lite are exterior bars placed on the surface of the glazing and an interior grille within insulated panes of glass. The interior grille does not hinder the argon filled glazing, retaining the window’s thermal performance. The exterior bars are adhered to the window surface with a strong adhesive tape. These are either applied in the factory or in the field if the project is high-altitude and/or requires site glazed windows and doors. Unlike their historic predecessor simulated divided lites add expense to the window package and are often the first item eliminated when budget becomes a factor.
An ever-increasing understanding of window performance and its importance, ushers in the double and triple pane window. The addition of another pane of glass makes the design of the simulated divided lite even more critical. The interior grille is now inserted between three layers of glass instead of two. Plus, the attachment of an exterior applied grid to further substantiate the faux historic look can become cumbersome. When selecting your simulated divided lite seeing a real-life example can make a world of a difference. Depending on your climate, double pane windows are your best option for appropriating the SDL for your window design.