On Tue, 03 Apr 2007 11:44:50 -0400, Goedjn wrote:


Ok, but that doesn't mean that it's a helpful scenario.
Thermopane windows are primarily designed to keep heat *IN*. They

Is that so?

depend on low-E films and similar treatments... Well. let me try some

There was thermopane before there was low-E. (And isn't that still
the case?)

It was just plain window glass glued together with air in between. It
was meant to be like a storm window but more convenient. When you
opened one pane, you did the same to the other pane. So if you wanted
fresh air, you only had to move one thing.

And also very good for doors. We had a big sliding glass door, but
there was no reasonable way to make a storm door for it. Thermopane
solved that.

And it was meant mostly to keep the heat in, because we didnt' have
AC. For those who had AC, it would also keep the heat out.

sample numbers . . . .

Ok, apparently, the inner pane has to be around three times better at
converting light to heat than the outer pane for it to make matters
worse. So if both panes are the same material, you're definately
better off with multiple panes, even if you are trapping hot gas
between them. (The difference between energy reflected and
energy converted is too complicated for be to bother modelling,
esp. if I'm conceding the point on the basis of the simpler
model anyway.)

But here I have no disagreement.