Posted By gregj on 03/31/2008 3:29 PM
Panelcrafter, I looked at your calculator and have some questions.
If using ICFs do I use the "concrete" row and change the R value to that of my ICF? Use either 2x4 or 2x6 and change the R-Value.
For SIPs what row do I use? Again, use 2x4, 2x6 or 'Concrete Air', and change the R-Value. Do not use 'Concrete Earth' as the Delta T is based on the Earth temp.
If I'm figuring 2x4 walls do I put in the R value of the fiberglass batts that I'm using (say R11) and does it adjust for the conductance of the lumber and use an effective R value of say R9?
If I use foam boards over the 2x4 with fiberglass batts how do I enter that? You need to figure your whole wall R-Value. You can calculate that as a ratio between the insulation and studs, or however you choose. The software uses the R-Value that you give it. So, R-9 doesn't sound that far off. Foam board: Again you need to decide on an R-Value to use, and use it for that category of wall.
Good Luck!
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