how much difference in price and quality between R19 and R20 per square feet ?? ) } p# K- |* ? ( Y2 O* e$ l! \ u. g. g 7 F- w. s+ Z/ R7 [4 d2 iwho can explain why use R30 for attic. / Q. K# i; ]! v ( q. j( d j# X) g- [( B' r2 ^Thanks
1#KochFord " ?3 i$ M) |" y3 p6 eThe higher R value, The better insulation performance. & h* B6 i0 n' I0 uIn 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. / p5 j* \+ D2 ^$ ?: ]8 ?& AHope my answer helps.