Our house was built in about 1913, in a simpler style on the footprint of the original--it burned--high-Italianate Victorian. You could call it a Colonial Revival looking back at Queen Anne. It has high ceilings, two staircases, lots of nice detail, 35 oversized leaky 8 over 1 double-hung windows with ugly ill-fitting uncaulked aluminum storms. All have working weights in the uninsulated pockets. It's a bit of a local landmark.
We must replace our heating system, which is grossly inefficient, and would love to go geothermal. In preparing for that, we are tightening up the house to reduce the BTUs required to heat it. We have added insulation in the cellar and attic which the insulation people think will reduce the BTUs by about 20%.
The question is, what to do about the windows. I described the house in order to explain why I am so resistant to vinyl replacement windows. We have prices ranging from Harvey Slimline Vinyl (ugh) at $15K installed to Anderson400/Marvin (very nice) at about $28K plus probably another $3.5K installation for a total around $32K. We also have a price for Harvey Tru-Channel white aluminum storms installed at $11.3K. To that we could add the cost of having someone disable the weights, insulate the pockets, possibly add weather-stripping, and install some kind of balance or friction channels, which I'm figuring would add another $3.5K for a total of about $15K. There is one more window quote to come in, which is a locally-made replacement window with wood interior/clad exterior that should be significantly cheaper than Marvin/Anderson.
My questions are these:
A)Do you think that the storms-plus-renovating method will result in a significant BTU savings, and if so about how much? (Our current window situation is probably closely equivalent to single pane.)
B) How do you think this would compare to replacement windows?
C) Do you think that "friction channels" will work in our kind of window, or would something else be preferable?