Condensation on windows is one of the most common concerns for homeowners. But is it a sign of a faulty window, or just a natural byproduct of modern insulation? This guide breaks down the different types of window condensation and explains when you should be concerned.
What Causes Condensation?
Condensation occurs when warm, moist air comes into contact with a cold surface. The air cools and can no longer hold as much moisture, so water droplets form on the cold surface, your window in this case. Think of a cold drinks glass "sweating" on a warm day; it's the same principle.
Types of Window Condensation
Where condensation appears on your window makes all the difference.
Condensation on the Inside (Room Side)
This is the most common type and is usually not a sign of a window fault. It's a sign of excess moisture inside your home. Activities like cooking, showering, drying clothes indoors, and even breathing add moisture to the air. When this warm, moist air hits a cold window surface, condensation forms.
The Solution: Improve ventilation. Use extractor fans in kitchens and bathrooms, open windows briefly to allow moist air to escape, and consider using a dehumidifier in high-moisture areas.
Condensation Between the Panes
If you see fogging or misting trapped between the two panes of glass in a double-glazed unit, this is a more serious issue. It's a clear sign that the seal around the edge of the sealed unit has failed. Once the seal is broken, moist air gets in and cannot escape, leading to a permanent foggy appearance.
The Solution: The sealed glass unit needs to be replaced. In many cases, this can be done without replacing the entire window frame. The good news is that if your frames are in good condition, replacing just the glass is a cost-effective fix.
Condensation on the Outside
You might be surprised to see condensation on the outside of your windows, but this is actually a sign that your windows are working perfectly. It typically occurs on cold, clear nights and mornings. The outer pane of a highly energy-efficient window is well insulated from the warmth inside your home, so its temperature drops to match the cold outside air. When this cold glass meets moist air from outside, condensation forms.
The Solution: Nothing! This is a positive indicator of your window's thermal efficiency. The condensation will evaporate naturally as the sun rises.
When to Be Concerned
- Persistent condensation between the panes: This indicates a failed seal that requires glass replacement.
- Severe condensation leading to damp or mould around the window frame or on surrounding walls: This is a ventilation issue that needs addressing to protect your health and your home.
- Condensation accompanied by draughts or visible damage to frames: This could signal that the whole window unit needs replacing.
How New Windows Can Help
Modern double and triple-glazed windows are designed to keep the inner pane of glass warmer. This reduces the likelihood of internal condensation forming on the window itself. However, it's worth noting that highly efficient, airtight modern windows can sometimes increase condensation in other parts of the home if ventilation is not adequate. Installing trickle vents in your windows is a good way to allow a constant, controlled flow of fresh air.
Need Advice?
If you're experiencing condensation problems, we're happy to take a look and advise whether a simple repair or a full replacement is the best course of action. At Rapide Frames, we've been helping Lincolnshire homeowners for over 35 years.