Repairing Double Glazed Windows When Double-glazed windows "blow" in the wind, the gas that insulates them, argon, escapes, causing them reduce their energy efficiency. The good thing is that blowing double glazing is usually repaired without needing to replace the windows. The most common indication of a failing window seal https://www.repairmywindowsanddoors.co.uk/woodleywindowrepair/