Window Noise Reduction

(Question from a reader in the USA)

Hi. I am looking to see if you can help with an STC issue.

The issue I have:

I used a 1/4" piece of glass, which is 1.5 sqft, for a door. Glass STC Rating is .31.

If I change that glass into a laminated with an STC .35 will there be any kind of difference?

So the question is does a .31 vs .35 STC rating make a difference at 1.5 sqft?

Thanks.

Reply from Noise Help:

A window of 1.5 square feet is still a big gaping hole as far as noise is concerned, so reducing the amount of noise coming through will be an important gain in overall soundproofing in the room. Even mail slots, key holes, and gaps between the door and the frame can leak significant amounts of noise, so the window is definitely worth addressing, especially if you've identified it as a weak spot in the room. (Windows are often the first weak spots that need to be addressed.) Laminated glass is a good choice.

Going from an STC value of 31 to an STC value of 35 will result in a 60% reduction in noise, measured as sound intensity. Perceptually, to our ears this will sound like about a 25% reduction in perceived loudness of sound coming through the glass. It will be a noticeable improvement, and it's a start. However, if you're dealing with a serious noise problem, it's likely that this degree of improvement will not be enough to resolve it to your (or a client's) satisfaction.

Here are a couple of pages from Soundproof Windows' excellent website, which might help give a little more context for these numbers:
Window STC Ratings
Window Noise Reduction Comparison

Good questions. I hope this helps.

Regards,
Sarinne