definition of stc
What is an STC Rating? STC stands for Sound Transmission Class. Basically, STC ratings are an established way to average how much sound is stopped by something. STC ratings are used for windows, doors, walls and most building materials. For windows, STC ratings range from 18 to 38. STC ratings are the ONLY way to accurately compare various noise reduction products. An STC rating is an instrument measurement of how much noise is stopped. The STC ratings allow accurate âapple to appleâ comparisons. The STC rating is the average amount of noise stopped at 18 different frequencies, measured in decibels.