2 y/ b- P- B/ n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. 9 l; v* O, ? y$ h# E# X 0 R; Y: D3 } I2 A* y
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.