Posted by daestrom on September 10, 2006, 4:02 pm
The thing to remember is that steel has a higher thermal conductivity than
wood or concrete, the thermal conductivity alone is not the final
determination. Because steel is much stronger, a steel 2x4 is has a much
thinner cross-section than a wooden 2x4. And it is thermal conductivity
times the area, divided by the length that determines the overall heat
transfer coefficient (i.e. R-value). So a very thin sheet of steel folded
appropriately for ridgidity has a very small cross-section and is thus has a
higher R value. It may be '2" ' (actually 1.5) on the face, but the heat
must flow through a thin (1.2mm ??) webbing to get to the other 'face'.
Posted by nicksanspam on September 10, 2006, 9:50 pm
section than a wooden 2x4. And it is thermal conductivity times the area,
divided by the length that determines the overall heat transfer coefficient
Posted by SJC on September 11, 2006, 12:01 am
I think the point was made even without numbers. It is when you
get comments like "thermal diffuser" that I think you need hard numbers.
If you look at the web site the orginal poster suggested one part says:
Does the Steel Transfer Heat & Cold?
Yes. Insulation companies performed energy efficiency tests on steel framing
and found that when a steel home is insulated properly, the transfer can be
reduced or eliminated.
So much for "geen homes"...
Posted by Biff on September 11, 2006, 12:17 pm
Steel doesn't grow on trees capturing solar energy.
Posted by Jeff on September 11, 2006, 2:39 pm
The first *commercial* use of steel in shipping came as the high quality
woods necessary for construction became rare and expensive. These were
hybrids, with steel ribs and wooden sides. Not a good design! Or so I
seem to remember hearing...
Steel stud construction has it's own economic reasons and needs
special techniques to get around the thermal breaks in the skin. We need
to transition to all steel houses that will keep us warm in summer and
cool in winter...