In article , "Edwin Pawlowski" wrote:

"kevin" wrote in message

Other than that, the air itself will provide decent insulation.

-kevin

If that is true, why don't they just leave the air space between the
sheathing and drywall in a house? Why do we waste money putting up all the
fiberglass?

1. There's typically a lot more outside wall than there is
floor (in terms of square feet). More heat loss.

2. Because warm air rises and the walls are therefore
normally a lot warmer than the floor. More heat loss.

3. And most of all, because the outside walls are subject
to the wind chill effect. More heat loss. The floor is
insulated by the dirt and rock -- quite a few feet of
it too ;-)

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