Repairing Double Glazed Windows When Double-glazed windows "blow" in the wind, the gas that insulates them, argon, escapes, causing them lose their energy efficiency. The good news is that blown double glazing is often repaired without needing to replace the windows. The most typical indication of a failing window seal https://www.repairmywindowsanddoors.co.uk/stneots-windowrepair/