"D. Gerasimatos" wrote:

In article ,
Duane Bozarth wrote:

[snip!]

I'm looking at an addition to the house for sometime the next couple of
years...it's a frame two-story square farmhouse built 1914-15. Windows
are double hung w/ leaded glass upper lights. Nine narrow vertical
sections w/ overlapping triangles at the top and bottom which make a
2-1/2"-sq diamond pattern across the top and bottom ... anybody able to
do that w/ double glazing? So far, I've not found even a wood window
that is a close enough match although I haven't yet done a custom-made
request. I may learn how to do the leaded glass and end up building
them myself except I can't do double pane. (I have all the shop stuff
needed and am making new ones for the barn now--they weren't painted for
50 years so they didn't last).

You don't need to do a double glazed window. You can use insulated glass,
instead. You will need to have these custom-made, of course. I used
insulated glass in my 1929 English and it looks much more authentic than
a double glazed window. It insulates sound better than a dual pane window,
although it is not as energy efficient. However, I am of the opinion that
energy efficient windows are a little silly anyway since they are after
all windows letting in light and (when open) air. They are never going to
insulate like a wall can and will always be a place where energy is lost.
The one drawback of insulated glass is that it is HEAVY. If your
double-hung windows work with weights like mine do then you will need
a bigger weight and sometimes a bigger weight just won't fit.

Well, sure they're going to be an energy leak as compared to a R11+
wall, but there's no sense in not doing something to improve their
efficiency. A small improvement in a large loss is often much more
cost-effective than a large improvement in a small loss. With
increasing energy costs this is only going to be more significant in the
future.

These will be new installations so they'll go into standard modern
frames. The existing windows were retrofit into frames ditching the
window weights a number of years ago when Dad remodeled the house after
my grandmother passed away.