Heat preservation performance: The heat preservation performance of aluminium alloy is not as good as that of plastic steel doors and windows, but because the heat transfer coefficient K value of window according to the formula k=1/(1/ai+Rw+1/ae) depends not only on the heat transfer resistance Rw of the form itself (reciprocal of the heat transfer coefficient of the form itself), but also on the form. According to another calculation formula k = k frame f + K glass (1-f), the heat transfer coefficient K value of window is composed of K frame, K frame and K glass of window frame, fan component and window glass, which is directly related to the ratio of window area to f, while the ratio of aluminium alloy window to window area is about 10% smaller than that of plastic steel door and window. Moreover, the aluminium door, window frame and fan profiles are not solid, and the wall thickness of hollow aluminium profiles (actual hot bridge) is about 40% smaller than that of plastic profiles.
Plastic steel doors and windows are welded, so their air tightness should be slightly better than that of screw-connected aluminium alloy doors and windows. However, aluminium alloy doors and windows profiles have higher dimensional accuracy and tight matching between frames and fans, so they are still at a level. Sina Leju.]6F'G!Q