[1] Storm windows exist in North America, but are uncommon in continental Europe, where double, triple or quadruple glazing is prevalent.
[2] On modern houses they serve on existing windows in order to improve their thermal insulation[3] and soundproofing.
Aside from insulation, external storm windows provide an additional measure of protection for homes against damage to costly glass panes during inclement weather such as hail.
These aesthetic issues can be minimized by single line storm sashes, the incorporation of vent holes, and a properly sealed fit.
Modern storm windows often feature low-e glass, which improves energy efficiency by reflecting heat.
Installing storm windows can be a DIY project, requiring tools like a screwdriver, caulk gun, and putty knife.