On Jul 27, 10:20*am, "Existential Angst" wrote:
Awl --

Recently, on one of these How They Do It ditties, they featured but more
Dubai profligacy, this time indoor skiing in the middle of the effing
desert.

The key to the insulation, they explained, was a huge air gap, asserting
that air -- caveat: *trapped non-moving air -- was among the best
insulators.

First, is this true? *Before I insulated my roof, that air would become
blisteringly hot, and it didn't seem to be moving much. *That attic seemed
like a pretty good air gap to me, and it didn't seem to be doing much
insulating.

Second, I seem to remember one strategy where push/pull fans were used with
air gaps in a roof-type situation, to keep air flowing, to reduce the
heating transfer, like what accumulated in my attic -- ie, the exact
opposite of static air.

Now mebbe air behaves differently in conduction vs. *radiant* heat from
roof-type situations that is making the attic so hot, not hot air itself -- *
if the two can be distinguished wrt air.

iirc, the Dubai ditty used reflection, insulation, AND that big air gap......

But I've read about this insulating property of air before, so I'm wondering
how it might be employed in a house.

It actually is employed in your house if you have fiberglass
insulation.
The fiberglass essentially traps air within the fiberglass so that it
cannot move. Air that does not move will not transfer heat very
effectively.
That's why if you crush the insulation down and compress it, you
greatly reduce the R value.

How that applies to the Dubai ski facility, I'm not clear on. I
agree with your reasoning that if it's just a closed air space
similar to an attic, it won't work, because the air will move
via convection.






It would seem that if air itself was so good, solid insulation wouldn't be
so high a priority

I wonder what mooslims think about Dubai.....
--
EA