how much difference in price and quality between R19 and R20 per square feet ?? . I" e$ P6 X- Q! d! h( d, _ ! `( M+ b; h1 R3 W9 r9 v/ N& L5 C3 ^$ m4 @% I
who can explain why use R30 for attic. 4 w( |4 h$ `% v5 u9 f& {6 j% I6 r0 Q' v
Thanks
1#KochFord% o* [& P$ \) Z( Q/ z
The higher R value, The better insulation performance. ; T; s# E$ Z- G! iIn 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.8 z$ _+ u$ n' D1 r" ~
Hope my answer helps.