Understanding Why Your Windows Mist After Wild Weather
It’s a common question homeowners ask, especially across the UK where weather can shift rapidly: “Why do my windows mist up after a storm or sudden temperature change?” If you’ve noticed foggy patches forming between the panes of your double glazing following a weather event, you might be witnessing the early signs of a failed sealed unit.
Causes of Misting After Storms or Swings in Temperature
Double-glazed windows rely on a sealed air or gas-filled gap between two panes. When that seal fails, moisture from outside air can seep into the gap, leading to condensation that is trapped inside, creating a misted or cloudy appearance.
Storms and temperature fluctuations impact your windows in the following ways:
- Pressure Differences: Sudden drops or increases in air pressure during storms can stress the seal, causing microfractures or expanding existing weaknesses.
- Thermal Expansion: Glass contracts when cold and expands when hot. These shifts, especially sudden ones, can weaken the perimeter seal around your insulating glass unit (IGU).
- Increased Humidity: Storms often bring higher humidity, and if windows are already compromised, that moisture will find its way inside the layers of glass.
How to Know If It’s Just Surface Condensation or a Blown Unit
Not all misting is a sign of permanent failure. Here’s how you can identify the difference:
- Exterior misting (outside pane): Usually visible early mornings and clears naturally—this is normal and even a sign of high-efficiency glazing.
- Interior surface misting (inside your home): Caused by inadequate ventilation or high humidity indoors.
- Condensation between the two panes: This indicates a blown sealed unit and requires professional replacement.
Why Replacing a Blown Unit Matters
Once the seal fails:
- Your window loses its thermal properties, leading to heat loss and higher energy bills.
- Moisture trapped inside can lead to mould growth and decreased visibility.
- It can impact the property value and long-term condition of your frames.
Can Weatherproofing Prevent This?
While storms are unpredictable, some steps can reduce the chance of a unit blowing:
- Ensure your windows are professionally installed and properly sealed.
- Check regularly for tiny gaps or cracks around the beads or sealant lines.
- Install trickle vents to allow pressure equalisation and ventilation without opening windows fully.
When to Call a Professional
If your windows consistently mist after a storm—or if only one window in the house seems affected—it’s a good sign of an isolated seal failure. Replacing just the affected unit is quick, cost-effective, and doesn’t require changing the whole frame.
At Get My Windows Fixed, we specialise in diagnosing misted double glazing and restoring your windows’ clarity and energy efficiency by replacing only what’s necessary. We work across the UK, including cities like Leeds, Glasgow and Bristol, and can provide free quotes based on your photos and window measurements.
Ready to clear the fog? Click here to get a quote today and bring the view back into focus.