I've been reading all these posts on the mutitude of so-called "Green" websites and blogs with great interest. They mostly say you should get rid of your old and historic windows in favor of disposable replacement windows. This is truly anti-green and anti-energy efficiency!
Over the years I've been around and worked on many steel casement windows in Tudor Revival style homes as well as commercial buildings. They were popular from about 1910 to 1935. I've also seen many homeowners rip them out and replace them with inferior and less energy efficient windows.
Many people have said to me they need new windows because they fear lead paint, want better soundproofing, energy efficiency and easy cleaning. Then the answer is to restore original windows, not replace them. Restoration will cost less and the windows will be lead free, soundproof, energy efficient and easily cleaned.