How can I soundproof my apartment windows from street noise? Heavy curtains and weather stripping help a little, but most street noise comes through the glass and gaps. The most effective option that doesn't require replacing windows is a secondary insert that sits inside your existing frame, creating an extra air gap and glass layer. Check that the insert is custom-fit, seals tightly, and is removable if you rent. Measure your window carefully first. Our guide covers how: https://soundproofusa.com/how_to_measure_for_your_window/