[MassHistPres] lifetime costs of historic vs vinyl windows

[Dennis De Witt]

I have just come across a useful, Boston based, study comparing the lifetime costs of historic wood windows plus Harvey tru-channels with Harvey vinyl replacements.  

http://blogs.bostonmagazine.com/boston_daily/files/2011/06/Grant-Final-Report-12-3-2010.pdf

It makes it clear that the replacement windows make no economic sense.  As good as it is, there are two omissions that would have made this an even more useful study
.
a) It assumes the insulating glass (IG) will fail and thus degrade performance due to water vapor in the IG, but it doesn't assume that a failed steamed up IG sash will have to be replaced.  It also assumes failure will take 35 years, which is optimistic, given that IG is typically guaranteed for only 10-15 years.

b) It assumes the historic window is in good condition and needs no work.  Charts factoring that in, perhaps at a couple of different levels of required work, would have been helpful.

Dennis De Witt
Brookline