One of the chief virtues of double glazing is its ability to reduce noise pollution.  The layer of vacuum (or inert gas) which sits between the two panes will reduce the amount of noise transmitted by as much as three quarters, which in most cases is more than sufficient. That said, if you’ve recently bought a home beneath a flight path or next to a train line, you might want protection that’s a little more substantial.  This can be achieved by placing an additional layer of special acoustic-dampening plastic between the window panes.  This plastic will absorb the sound waves, thus preventing those vibrations from finding their way into your home.