In order to completely soundproof a room, then it’s necessary to block the incoming – or outgoing – noise from the windows, as well. In fact, failing to soundproof the windows in such a room will render the rest of your efforts ineffective. Laminated glass with tight seals, as well as double glass layering is the only effective way to soundproof a window. Although some companies claim that plastic coverings will do the job – specifically, those which employ either Velcro or magnets to hold the plastic in position – this is nothing more than a myth. At best, it might reduce the amount of noise that comes in from the outside, but it certainly can’t be considered a true soundproofing technique. Why? Simply because it doesn’t utilize the mass or space methods, and the seals are usually inadequate for keeping out noise. In fact, the only benefit that you might derive from this type of covering is a degree of insulation from the elements. As far as soundproofing is concerned, though, you can expect as little as a 5% reduction of noise.