The thermal improvement is great. But acoustically, not so much.

In fact, the Andersen double pane casements seem noisier than the 50 year old original single pane casements. When the new windows are closed tightly, outside "white noise" (like wind or distant traffic) turns into a distinctive rushing or humming noise.

In fact, it sounds as though the window is next to a water pipe with water running through it.

Now I like the sound of running water as much as the next person, but it gets pretty tiresome to have it going for hours on end. In the bedrooms. And in the office.

FWIW, we put Pella windows in 10 years ago as part of a master bedroom remodel, and they are quiet as can be.

I contacted Andersen, and they said that this was something they had never heard of (so to speak).

Now I'm wishing we had stuck to Pella.

Just wondering if anyone else has experienced odd window noise with Andersen 400 casements?