Instead of storm windows which are a pain why not just replace the windows you have with the same look in a double or even triple paned glass, there are companies that specialize in these replacement windows in heritage buildings.

Historic house prohibition on any change to original exterior. Bummer.

I suggest you first have a good carpenter look at your windows and do any necessary repairs. That alone could improve the issue with drafts. If it were my home I would then get wood storms and screens (if you need screens where you live). They are a bit of a pain to switch and require some maintenance, but will be authentic in appearance and work quite well. Also, much less expensive than new windows...

You can replace windows with modern double or triple paned without having a problem as long as the windows look the same my son does historic renovations and all the buildings he has done have new windows but they look exactly the same.

Cape Ann has a fairly stringent historic preservation code, though I don't know their take on historic windows ( I used to summer there) Here in savannah if your home is historic you have wood single pane windows period. They will allow exterior or interior storms. An historic wood window with an exterior storm window is AS EFFICIENT OR MORE EFFICIENT than a replacement window. And will usually last longer. A window salesman will never tell you that though.

Oh and this post is from 2014 so they have already installed their new windows, wonder what the chose?

What did you choose?