wrote in message
oups.com...
We're new homeowners. We have a house with ten double hung windows with
double panes. They're by Thermal-Guard. They look old, but I don't
really know their age. Each window has at least one sash with bad
condensation between the panes. Many have condensation in both. Some
have discolored film between the panes (?). Some have broken springs.

The question is: Should we replace the complete windows? Or just the
bad glass "sealed units" and fix the springs separately (possible?)?

Not seeing the original windows, it is hard to say. Old means nothing.
There are houses that have 300 year old windows and they still function as
intended (but not as efficient as new). If yours are otherwise well made,
replacing the glass is all that is needed. If you have rot, different
story. Do they go up and down well? Seal well?. If yes, I'd replace just
the glass.

Replacing the entire window opens a large list of other possibilities, such
as damaged trim inside and out, repainting a lot of stuff, and on and on.