Noise reduction refers to the amount of sound which is removed as it passes through a closed window or a wall.
However no matter how good the window is at keeping noise out, if it is not installed and sealed properly during construction, noise will still penetrate the home – all air gaps must be sealed off to ensure that a window will achieve the best noise reduction it can.
The Sound Transmission Class (STC) reflects the amount of noise that is reduced when sound passes through the window. So if the noise outside is 70dB and inside it is 40dB, the window is said to have an STC rating of 30. Normally the human ear cannot detect a 1-2dB change in sound. However a 10dB decrease in the sound is subjectively heard by the human ear as a halving of the sound – e.g. a 40dB noise seems half as loud as a 50dB noise. The average spoken conversation makes a 50dB noise, while common street traffic and neighbourhood sounds make about 70dB noise.
Sound waves are what carry noise into a home. To achieve noise reduction you must disrupt the sound waves as they travel through the windows. Using standard glass and window options you will be able to disrupt a sound wave.