Understanding STC Ratings

Life and work in a busy city or suburban area can get loud, and as our communities grow, so does the noise. The constant blare of car horns, screeching of trains, and barking of dogs can become a major headache, affecting your health and quality of life. The good news is that you don't have to just "get used to it." There's a solution: CitiQuiet soundproof windows.

A quick online search for soundproofing products will bring up thousands of options, leaving you to wonder which product will work best. That's where the Sound Transmission Class, or STC rating, comes in. The STC rating is a universal system for measuring a product's soundproofing capabilities, making it easy to compare and select the right solution for your needs.

What Is an STC Rating?

STC ratings measure how well a barrier—like a window, wall, or door—reduces airborne sound. The higher the STC rating, the more effective the product is at blocking noise. This system is the most widely accepted method for measuring sound reduction, giving you a reliable way to gauge a product's performance.

While STC ratings can apply to many types of building partitions, they are most often used for walls and windows, which are the most common entry points for unwanted noise.

How Does an STC Rating Work?

To truly understand how STC ratings are calculated, it helps to know a few basic principles of sound:

• Frequency: Measured in Hertz (Hz), frequency refers to the pitch or tone of a sound. Low-frequency sounds, like a deep voice, are different from high-frequency sounds, like a flute.
• Decibels (dB): This is the unit used to measure the loudness of a sound. On the Sound Pressure Scale, 0 dB is the softest sound a human can hear, while sounds at 130 dB or higher can be painful and damaging.
• Transmission Loss: This is the difference in volume (dB) on one side of a barrier versus the other. For example, if a television on one side of a wall is at 100 dB and you measure the sound on the other side at 75 dB, the wall has a transmission loss of 25 dB.

To determine a product's STC rating, testing is done across 16 standard frequencies. The transmission loss values at each frequency are plotted on a graph, and the resulting curve is compared to a set of standard STC reference curves. The product is then assigned the STC rating of the curve it most closely matches.

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Window STC Rating Chart

 

Below is a typical STC rating chart that shows the estimated performance of different window types. This is a great way to see how soundproof windows compare to standard windows.

STC Rating	Window Type	Expected Results
26-28	Single-pane window	You'll hear most outside noise.
26-32	Double-pane window	You'll notice some reduction, but loud noises are still clear.
48-54	CitiQuiet Soundproof Window	The noise is significantly reduced. You'll hear very little, if any, outside sound.

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Why Choose SoundproofUSA and CitiQuiet?

 

Soundproof windows are an excellent way to create a more peaceful and comfortable living or working space. CitiQuiet soundproof windows have some of the highest STC ratings on the market, making them highly effective at blocking noise.

In fact, our windows are proven to reduce outside noise by up to 95%. When you install CitiQuiet, you're not just buying a product—you're investing in a quieter, more peaceful life.

Ready to see how SoundproofUSA and CitiQuiet can transform your home or office? Contact us today to learn more about our solutions.