I have the same problem. But the prior owner just slapped on permanent storm windows over the original windows with a 4" gap between windows.
Trust me, I've discovered far worse from this dingleberry over the last 26 years!
It's still on my pending list.
In the meantime, is Pella still a good company? You get varying opinions. I figured I'd ask you as anyone who makes a window you like in your climate is who I want to go with! :-D