If you've been told you might need a 'sash replacement,' you're not alone in wondering what that even means. The sash is simply the framed, glazed panel that holds the glass — the part that moves when you open the window.
Sash vs frame
The frame is the fixed perimeter anchored into the wall. The sash sits inside that frame and carries the glass. On a double-hung window, the upper and lower panels are both sashes.
Why it matters on clad wood windows
On aluminum-clad wood windows, the sash and frame are premium components, and the sash often carries the sealed glazing. When a seal fails and the glass fogs, the issue is frequently at the sash level — which is why sash replacement can be a targeted path when the frame is sound.