Ian Stirling wrote:
The second will win.
You don't say...
As to the leading - it's largely irrelevant.
Glass has a K of 1, so a 6mm pane has a U value of 1*.006= .006.
The air sitting next to the inside of this utterly swamps this in
insulation.
I dunno - lead has a K of ~35. Steel has a K of ~46. If we take one
opening pane, which is 49cm wide by 90 cm high:
Total area: 4410 cm^2
Glass: 3563 cm^2
Steel: 540 cm^2
Lead: 307 cm^2
That means the glass only makes up 81% of the window area, with the rest
of the area being made up of materials that are over an order of
magnitude more conductive.
--
Grunff