Those of us attracted to this forum have an appreciation for original window sashes and such. The problem is that most in the marketplace do not. We have all seen it, around here beautiful, 19th century houses are routinely razed and replaced by McMansions. A big part of the problem is lead paint and where do we always find lead paint- on the sashes. For those few who actually restore original windows (such as me) where do you get the storm windows? They're gonna have to be custom made right? I searched and searched and finally found The Burch Company in Baltimore, still in business only barely. Another grievance of mine is the slate roofs. I live in an area with beautiful, black slate roofs on all the buildings build before 1920, even sheds and barns. New people who move in don't recognize slate and pull it off and put on the cheap stuff, it happens every day. These actions are governed by the marketplace, so many times the work goes to the low bidder.

Whether they are worth anything in the monetary sense depends entirely on their condition, what a buyer would be willing to pay, etc. Their real worth lies in their historical significance and the considerable role they play in the overall architectural integrity of the building they are in. IMHO, the fad for removing beautiful old windows, tossing them in the landfill and replacing them with short lived "energy efficient" replacement windows is an ongoing tragedy and a huge consumer fraud. Unless they are hopelessly damaged, old windows are superior to any you could buy today and are well worth repairing. Read the fine print in today's replacement window advertising and see if you think any are likely to be around as long as ones made in 1834. Old windows fixed, weather stripped, supplemented with high quality exterior and perhaps interior storm windows, will be just as "energy efficient" as the over-hyped stuff you can buy with their phony claims and short life spans.

With double pane windows you cannot just replace one layer of the glass . The entire glass hass to be repalaced. A reputable glass company can do it for you.

If you try to remove that pane and leave the existing, uncracked pane in place you will likely have a mess and possibly a loose remaining pane...if it doesn't get broken in the process. I suggest you leave it alone, or, for safety, run wide tape along the crack. If the crack is inside, you can use clear packaging tape; if it's outside, and under an overhang, you could use packaging tape there, too. Otherwise, use duct tape on the outside as it should be able to hold up to the weather until you can manage the window replacement. And you're right...a replacement of that size will be pricey.