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 ??
/ D. w, s$ d+ ~7 R
3 [+ S; m' e% a
who can explain why use R30 for attic.

Thanks

爱城飞雪

1# KochFord
The higher R value, The better insulation performance.
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.
9 d, B4 H" c% w+ vHope my answer helps.

爱城飞雪

1# KochFord
  G- S( [% J! j* j2 H# A

& W1 V' x  p/ R& JR19 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