/ a. p" _% E6 w3 ]3 R! O! d7 B. f
5 g- R8 {; R: k# I0 G# b
我家的房子,冬天上午, 太阳足的时候,自然达到25度。 房子02年的。I did upgrade the ceiliing insulation from R20 to R60 though. , Z- C2 I/ h2 O) s `2 W # L# @6 i! M8 b: J9 o+ T j( U
40% is lost from ceilling. 40% from windows. so 屋顶改进分别对保温性能贡献大. Costed me $2000, because I used the Pink insulation ( usually for walls) at the ceiling. If you use foam that usually for ceilling, then your cost should be only 1/3 of mine. Rent a foam spreader from HomeDepot.