(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

How thick a concrete wall would be needed to give the same insulating value as 3.5 inches of fiberglass?

2. Relevant equations

Q = -A·k·ΔT/Δx

k = -Q·Δx/A·ΔT

3. The attempt at a solution

So here, k is equal to the insulating value, and since I want the insulating value to be the same for the concrete wall and fiberglass, I would have the equation

-Q·3.5/A·ΔT = -Q·Δx/A·ΔT

Since it seems that area and change in temp are the same in both cases, I got

Q·3.5 = Q·Δx

Which is where I got stuck. Would the Q (heat flow) cancel?

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# Thickness of concrete wall to have the same insulating value of 3.5 in. fiberglass

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