how much difference in price and quality between R19 and R20 per square feet ?? + b& m3 U9 ~) ~7 b* a- U1 ? 6 G, H3 [1 {/ I; w a1 H" r. n1 p- F$ E/ r C
who can explain why use R30 for attic. 4 P) P8 [* ^# I% Z. Q2 \ / l* |" C4 q2 t3 v% B: ^' CThanks
1#KochFord * _- O/ [: @4 OThe higher R value, The better insulation performance. $ k& Q1 d; j# @" Z% jIn 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. U' w, S! c! h
Hope my answer helps.