R-Value Range

Insulation Type

2X4

2X6

Fiber Glass batt

R-13

to R-15

R-19

to R-23

Fiber Glass blow-in

R-13

to R-16

R-20

to R-25

Mineral wool batt

R-13

to R-15

R-22

to R-23

Mineral wool blow-in

R-14.5

R-23

Cellulose *

R-12

to R-13

R-19

to R-20

Spray Foam Open Cell**

R-12

to R-13

R-19

to R-20

Spray Foam Closed Cell**

R-19

to R-22

R-32

to R-35