Air: R (RSI) vs Pressure
I have been looking a bit on the internet and cannot find a graph for the relationship R vs Pressure of air. I am renovating my very old house and was pondering putting a vacuum layer, almost against the exterior finish. I understand a perfect vacuum would have an infinite R Value, and I read that closed air at 14.5 PSIA (1atm) has about R-1 / Inch. If I can only get my retrofit vacuum panels to 7.25 PSIA would I be looking at R-2/inch, R-10/inch, ...?
Anyone have some interesting thoughts?
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