On Nov 3, 9:20*am, Aaron Fude wrote:
On Nov 3, 5:56*am, "Ed Pawlowski" wrote:

"Tony Hwang" wrote in message
Hi,
Wondering if amount of air trapped inside the batt is same whether it is
compressed or loose? I understand R means resistance against air leak..

The more you compress, the less air trapped, the less insulation value.

I see this point but i would like to understand this. If you take this
argument to the extreme, then the least amount of insulation is best,
because that keeps the most amount of air inside the walls. So how
come just having air between the walls is bad insulation?


Because having just air means the air can move and readily transport
heat from the warm wall to the cold wall. With insulation filling
the cavity, there is still a lot of air there, but it's being held in
place by the insulation, so it's far more difficult for an air
molecule to go from one wall to the other.








Thanks,

Aaron