how much difference in price and quality between R19 and R20 per square feet ?? e4 L( Y9 x+ n" g# C # m' G! U+ B3 `* G) ]; k' u" J 4 u* q3 Q- \# d% y7 F3 E: nwho can explain why use R30 for attic. ! }4 I7 D- U8 S* M. s$ M- M# N* Z! t$ P
Thanks
1#KochFord % Q6 c2 X' j/ u! NThe higher R value, The better insulation performance. 7 P: v1 Y! j, E7 G$ i) o" |; F; L4 xIn 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. 6 a$ x6 H; G! THope my answer helps.