how much difference in price and quality between R19 and R20 per square feet ?? 6 x+ t/ L0 E9 p* f& d 0 p& t" t3 e5 k+ D" c/ g" l: l 5 N1 I# W: u( b$ _& V0 }who can explain why use R30 for attic. 9 u% ^& N+ }7 q! |; d0 @
1#KochFord2 L V, A3 q1 j2 h' c/ U
The higher R value, The better insulation performance. 8 s! h. b$ [ t4 p5 q9 E' GIn winter, the hot air always floats up due to thermal buoyancy, so R value for the roof is normally higher than that for exterior wall.: L8 ? O5 a, }7 w% Q O! h8 E/ V2 q
Hope my answer helps.