how much difference in price and quality between R19 and R20 per square feet ?? + G, n" j4 \* r9 W, ` 4 |% V% m& l2 n; y0 S) Y8 [7 V: O: A9 u- i* T* T3 b5 }9 W6 w* Z
who can explain why use R30 for attic. 9 { M4 d2 E* p w+ n4 v( }1 |
1#KochFord1 Q0 s. B, u' ~2 G" {
The higher R value, The better insulation performance.$ A e6 _3 C( m9 G" x
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.; ]/ P- z/ R9 Q6 E
Hope my answer helps.