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 ??
* ~4 t; R# x: K
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who can explain why use R30 for attic.

Thanks

爱城飞雪

1# KochFord
The higher R value, The better insulation performance.
0 x; |2 @; P- T- @4 \' z) MIn 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.
! u7 B/ j$ o4 B, P; w$ a, r+ }  jHope my answer helps.

爱城飞雪

1# KochFord

3 x9 L' M9 M; `4 D2 K8 ?+ W; O
R19 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