You replace the glass for the insulation value. You don't need to (and shouldn't!!) replace a wooden frame.
Replacing good wooden windows with vynil/aluminium windows is basically signing up to a subscription to the window company. You can't really restore that vynil crap, and the lifespan has a hard limit at 15 years when the double seal breaks.
I'm just replacing the panes and restoring the wood. On the parts where the wood rotted out, I'm replacing the crappy cheap wood with rot resistant hardwoods.
Modern windows aren't that much better. Window companies have good marketing.
A 200 year old single pane window is R-1. Double pane is R-2, and with argon maybe R-3 or R-4.5
Triple pane is R-3 to R-6 depending, and vacuum sealed glass is R-4 to R-14(!!! But no one buys that).
Changing an old window to a new one is often a stark difference because the old window leaked air. Not because the R-value is much lower. You can fix that with reglazing.
Replacing good wooden windows with vynil/aluminium windows is basically signing up to a subscription to the window company. You can't really restore that vynil crap, and the lifespan has a hard limit at 15 years when the double seal breaks.
I'm just replacing the panes and restoring the wood. On the parts where the wood rotted out, I'm replacing the crappy cheap wood with rot resistant hardwoods.
Modern windows aren't that much better. Window companies have good marketing.
A 200 year old single pane window is R-1. Double pane is R-2, and with argon maybe R-3 or R-4.5
Triple pane is R-3 to R-6 depending, and vacuum sealed glass is R-4 to R-14(!!! But no one buys that).
Changing an old window to a new one is often a stark difference because the old window leaked air. Not because the R-value is much lower. You can fix that with reglazing.