"SoCal" wrote:

A friend of my mine owns a century old victorian that still has much of the
original glass. The glass has actually sagged so the bottom is thicker than
the top.

Another spot to read about 'glass flow' is the urban legends
newsgroup- alt.folklore.urban
It's in their FAQ-
http://groups.google.com/group/alt.f...28d10c3c5b07fc



She feels that the they have historical value and doesn't want to
tamper too much with the house as it is worth about 900k. Any suggestions
*other* than cheap plastic to improve the insulation window performance?

She can buy expensive plastic. In the 70's, when oil was
expensive, there were a million businesses that installed 'inside
storms' - basically a plastic/lexan with magnetic edges which stuck to
the thin magnets they installed on the inside. It gave an invisible
third pane that went up and down easily, and stored easily.

There must still be some of these businesses around. [and if there
aren't, it isn't brain surgery to do it yourself]

Jim