In article m,
David Nebenzahl wrote:

On 1/25/2009 11:08 PM Smitty Two spake thus:



Well, this is very interesting. What do you think this means from a
heating/cooling cost perspective? If walls are so good that the heat
transfer through them is negligible, then most of the energy devoted to
climate control in the home goes to combat window losses. So, doubling
the R value, would halve the heating or cooling costs.

That depends, of course, on the number and size of windows, and the
proportion of window area to wall area in your house. (Well, plus window
orientation, prevailing wind direction, etc., but let's keep it simple.)

If your house was all windows, then yes, you might come close to halving
heating or cooling costs by going from single to double-glazed windows.

If a room is mostly wall, then ... you get the idea.



But, if my suggestion: "If walls are so good that the heat transfer
through them is negligible, then most of the energy devoted to climate
control in the home goes to combat window losses" is true, then the
window to wall ratio doesn't matter so much.