This product can cover up to 100 ft².
I bought two boxes, and covered just a little under 200 ft.² between some of the waste and trimming around windows that I had to do.
Per the Manufacturer: "R-values really don’t pertain to our panels or most composite/Vinyl panels on the market. it is the exterior foam or WRB’s you would be using on the wall prior to the Grayne getting installed that would create the R value you would be looking for."