how much difference between R19 and R20 insulation, need help, thanks

KochFord

how much difference in price and quality between R19 and R20 per square feet ??
3 t$ d. r7 S# R5 ]
9 ^# S  Y; Y2 O5 x
who can explain why use R30 for attic.

Thanks

爱城飞雪

1# KochFord
: H. ?' u$ y& ~$ q6 WThe higher R value, The better insulation performance.
3 u1 }5 g5 s( R; _, Y; S- o) [- 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.
Hope my answer helps.

爱城飞雪

1# KochFord
$ i5 u8 e/ f; I* N
1 T$ ?# }2 m1 w  H# \+ R3 \) y
4 S  n, q: x( R, N! J, M6 WR19 is not commonly used.

chic-yong

R值固然重要，但隔热材料更重要。即使R值相同，不同的隔热材料性能也是不一样的。

KochFord

谢谢楼上两位