R Values of Building Materials (Iowa City, IA)

The values for our building materials were found from the following website (http://www.coloradoenergy.org/procorner/stuff/r-values.htm).  We decided to use 11 as the R-value for our fiberglass insulation because we found that that is more common than the type used on the website.

The following table displays the values used:



Some assumptions that were used in our calculations of overall resistance are:

1) Concrete floor is 2 in. thick
2) Wall is made up of 10% studs and 90% insulation material
3) R value for Plywood is higher in the roof and floor because it is thicker than the walls.

CALCULATION:
All of the above R-values were placed into matlab as variables and the resistances of the stud, walls, roof, and floor were calculated.  Also, the total was found by the following equation:

U = ((1/Rs)*.1)+((1/Rw)*.9)+(1/Rr)+(1/Rf)

where Rs, Rw, Rr, Rf are the resistances of the stud, wall, roof, and floor.

Below is the screen shot from matlab with the final value.  You can also see the defined variables in the upper right hand corner.