Condensation in double glazing can be a frustrating issue for homeowners. It not only affects visibility but can also indicate an underlying problem with your windows. Whether you’re dealing with misted-up glass in the morning or persistent moisture between the panes, understanding why it happens is the first step towards fixing it.
In this guide, we’ll explain the causes of condensation in double glazing and the best solutions to keep your windows clear and efficient.
What Causes Condensation in Double Glazing?
Condensation forms when warm, moist air comes into contact with a colder surface. With double glazing, condensation can appear in three places:
- On the inside of the window (room-facing side)
- On the outside of the window (external surface)
- Between the two glass panes (inside the sealed unit)
Each type of condensation has different causes and solutions.
1. Condensation on the Inside of Double Glazing
If you notice condensation on the inside of your windows, this is usually caused by excess humidity in your home. Common reasons include:
- Cooking, boiling kettles, or drying clothes indoors
- Poor ventilation, especially in kitchens and bathrooms
- High indoor humidity levels due to lack of airflow
How to Fix It:
- Improve ventilation – Open windows regularly, especially when cooking or showering.
- Use extractor fans – Ensure bathroom and kitchen fans are working effectively.
- Invest in a dehumidifier – This helps reduce moisture in the air.
- Keep trickle vents open – If your windows have them, leave these small vents open to allow air circulation.
2. Condensation on the Outside of Double Glazing
Condensation forming on the outside of your windows usually occurs in the morning when the external temperature is colder than the glass. This is actually a sign of well-insulated double glazing, as it means the heat is staying inside your home.
How to Fix It:
- Wait for it to clear – This type of condensation is harmless and will disappear as the day warms up.
- Consider self-cleaning glass – Some modern glass coatings reduce external condensation.
3. Condensation Between the Panes of Double Glazing
If condensation is forming inside the sealed unit, this indicates a broken window seal. When the seal fails, moisture enters the space between the panes, causing misting that won’t clear.
Common causes of seal failure include:
- Ageing windows (seals degrade over time)
- Poor installation or manufacturing defects
- Excess exposure to direct sunlight (thermal stress can weaken seals)
How to Fix It:
- Check your warranty – If your windows are relatively new, they may still be under warranty.
- Replace the glass unit – In most cases, you don’t need a full window replacement. A professional can replace the failed double glazing unit while keeping the existing frame.
- Upgrade to energy-efficient glass – If replacing the unit, consider Low-E or argon-filled glazing for better insulation.
How to Prevent Condensation in Double Glazing
To stop condensation from forming in the first place, follow these key prevention tips:
- Maintain proper airflow – Use trickle vents, extractor fans, and open windows where possible.
- Regulate indoor humidity – Keep your home’s humidity levels balanced with a dehumidifier or moisture-absorbing materials.
- Upgrade old windows – If your windows are over 15-20 years old, upgrading to modern energy-efficient double glazing can prevent future condensation issues.
- Seal any leaks – Check for draughts around the window frame and reseal if necessary.
When Should You Repair or Replace Your Double Glazing?
If condensation is appearing inside the double glazing unit, the glass will likely need replacing. Here’s when to act:
- If your windows are under 10 years old, check your warranty before replacing.
- If only one or two windows are affected, replacing the glass unit is a cost-effective solution.
- If multiple windows are misting up, it may be time for a full window upgrade.
At Cove Glass, we offer double glazing repairs and replacements to restore your windows’ performance.
Need Help Fixing Condensation in Double Glazing? Contact Cove Glass Today!
If you’re experiencing condensation in double glazing, don’t ignore it—especially if it’s inside the sealed unit. Our expert team at Cove Glass can assess your windows and provide affordable repair and replacement solutions to restore clarity and insulation.
📞 Call us: 01252 318787
📧 Email us: sales@coveglass.co.uk
🔗 Learn more: Double Glazing Repairs & Replacements
Condensation in Double Glazing FAQs
Q1: Is condensation inside double glazing a serious problem?
A1: Yes. Condensation inside the panes means the seal has failed, reducing insulation and requiring glass replacement.
Q2: Can I fix misted double glazing without replacing it?
A2: In most cases, the sealed unit needs replacing. However, some specialists offer defogging services, but these are often a temporary fix.
Q3: Will replacing my double glazing improve my home’s energy efficiency?
A3: Yes. Upgrading to modern double glazing with energy-efficient coatings can reduce heat loss, lower energy bills, and prevent condensation issues.
