WHOLE HOUSE R-VALUE APPROXIMATION:

http://hearth.com/calc/btucalc.html
http://www.uoregon.edu/~cgyoung/r-19.html

The above links were used to estimate the whole house R-Value for Mr. Davis' home. The first link gave a rough BTU need of 20,000 BTU/h and based on this number and HOBO data, we estimated the whole house R-Value to be near R-9. The second link substantiated this, saying that the average home with R-19 insulation actually performs closer to R-13. Thus we give these two values as the possible R-Value range: R-9 to R-13.