Ways of double glazing
There are three basic ways of double glazing: Associative, secondary external (box) and secondary internal. The first way is to combine two panes into a hermetically sealed whole, which replaces the traditional single pane. Internal secondary glazing consists in fixing an additional glass pane or covering the glass with a plastic film from the inside. External secondary glazing consists in fixing an additional window sash from the outside.
The glass of most double-glazed windows is thick 4 mm. For glazing large sashes use tempered glass. A cheaper solution is to cover ordinary glass with a transparent plastic film (insulating and reinforcing).
Double secondary glazing
The simplest form of additional glass is to glue a thin plastic board to the window frame, fixed with double-sided adhesive tape. There are also many more sophisticated solutions, in which the second pane is framed in a plastic frame, mounted on the window with special trailers.
None of the described windows can be easily opened, which excludes their ventilation function, however, they can be removed for cleaning. The best fest solution is therefore to fix an additional glass on the opening window sash.