how much difference in price and quality between R19 and R20 per square feet ?? V5 i, P7 p- K0 ~: l* b 7 U2 q- s$ Q2 {6 _& ~ ! ~! n3 ]+ d* i8 A( g, V {. {who can explain why use R30 for attic. ' \1 N. f. X% @; v) x5 C 5 |* s2 v$ q4 \Thanks
1#KochFord % @* d* X p5 g) j* s4 t# BThe higher R value, The better insulation performance.; f( R$ ?# e8 }3 a# i) y c
In 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. " f) |6 ?$ r. G8 O# RHope my answer helps.