What causes condensation inside double glazed windows?
Condensation forms between the panes when the hermetic seal around the edge of the sealed unit fails. This allows moist air to enter the gap. When the temperature drops, the moisture condenses on the inside surface of the glass, causing the foggy or misty appearance. Read more on our Why Condensation Occurs page.
Can I fix foggy windows myself?
Yes! Our kits are designed for anyone with basic DIY skills. The process involves drilling small holes in the glass, allowing the moisture to evaporate, then sealing the holes with one-way valves that allow future moisture to escape. Full step-by-step instructions are included with every kit.
How long does the repair take?
The drilling and setup process takes about 15–20 minutes per window. After that, the moisture evaporates naturally over 1–14 days depending on the amount of condensation and the weather conditions. Some customers see results within 24 hours.
Will drilling holes weaken the glass?
No. The holes are very small (3–4mm) and drilled through only the outer pane. The structural integrity of the window remains fully intact. Thousands of customers have used our kits successfully without any issues.
Does this work on toughened glass?
Yes, but toughened (tempered) glass requires a diamond-tipped drill bit, which is included in our Toughened Glass Kit. Standard glass drill bits will not work on toughened glass.
How long does the repair last?
The repair is a long-term solution. The one-way valves allow any future moisture ingress to evaporate, so the windows stay clear. Many customers report their windows have remained clear for years after repair.
How much does it cost compared to replacing the sealed unit?
Replacing a failed sealed unit typically costs £100–£300+ per window fitted by a glazier. Our kits start from under £30 and can repair up to 4, 8, or 12 windows depending on the kit size, saving you hundreds or even thousands of pounds.
Do you ship internationally?
Yes, we ship worldwide. Our kits have been used successfully by customers across the UK, USA, Europe, and beyond. Shipping costs are calculated at checkout based on your location.