Sound Explanations: A Deep Dive into STC

By NanaWall Systems, May 17, 2018

Okay, so what is STC, and why should you care?

STC is an acronym for sound transmission class. Sound transmission class is a rating assigned to a particular material or product based on its ability to attenuate sound. It’s a rough reflection of a material or product’s ability to reduce the decibels of surrounding noise.

Where fenestration is concerned, STC ratings are useful because they give you an idea of how much noise said fenestration is going to let into or out of a space.

STC ratings can be given to the individual materials of which the window is comprised (like the glass for instance), or to the window as a whole.

In order to fully grasp the significance of STC, we’ll need a basic understanding of how sound transmission works.

Sound is energy that has been converted into wavelengths or vibrations. These vibrations, in order to successfully produce sound, need a material medium such as air, water, or metal through which to travel.

Sound transmission needs a source to produce a vibration, a medium to carry that vibration, and a receiver (e.g. your ears) to receive it, in order to be successfully transmitted.

However, if we are hoping to allow as little sound as possible from transmitting from one room to the next, then we will want to pay close attention to sound transmission loss (STL). STL measures how effective a given barrier (e.g. a wall or a pane of glass) is at preventing a sound from moving from one side of a barrier to the other.

The more STL a barrier can promote, the higher its STC rating is likely to be.

So how can fenestration increase STL, thereby bettering its STC? Join us next week for another installment of sound explanations to find out!

In the meanwhile, have questions about STC and NanaWall products? Contact us at