Double Glazing Unit Repair If You have double-glazed windows that appears cloudy or misty and isn't able to be cleaned, it's probably "blown". This happens when the space between the panes of glass expands due to the deterioration of the window seals. It is cheaper to replace the double-glazed unit http://www.stes.tyc.edu.tw/xoops/modules/profile/userinfo.php?uid=1211939