Window glass repair · Gurgaon & Noida
Fog between double-glazed panes in Gurgaon: a failed seal, and the fix
Mist between the two panes of a double-glazed window means the sealed unit has failed: its edge seal has let in humid air and the moisture-absorbing spacer is saturated. It can't be wiped or reliably dried from outside. The fix is a new sealed glass unit made to size and fitted into the existing frame.
Inside the unit, or on the surface?
Not all window fog is a fault. Condensation on the room-side surface on a cold winter morning is normal in a well-sealed flat, and condensation on the outside is a weather thing; both are covered in window condensation. This page is about the one kind you can't wipe away: mist, droplets, white tide-marks or a milky haze between the two panes.
Quick test: wipe both faces of the glass with a dry cloth. If the mist is still there, it's inside the sealed unit.
How a double-glazed unit works
A double-glazed unit (DGU, or insulated glass unit) is two panes held apart by a hollow spacer bar around the edge, filled with a desiccant that absorbs moisture, and sealed with a primary and secondary sealant. The cavity is filled with dry air or gas. It's what gives windows in newer Gurugram and Noida high-rises their noise and heat performance, especially along busy expressways.
As long as the edge seal holds, the air inside stays dry. Once it fails, every day's heating and cooling draws a little humid air in, the desiccant fills up, and moisture condenses on the inner faces.
Why the seal fails
Age and sun
Edge seals degrade with UV and temperature swings. West-facing windows in an NCR summer see big daily cycles between hot afternoons and cooler nights, which pump the unit and stress the seal.
Water standing on the edge
If a frame's drainage is blocked, rainwater sits against the bottom of the unit. Prolonged wetting breaks the seal down from the bottom up. Clear weep holes matter for this reason.
Poor manufacture or glazing
A unit with thin or gappy sealant, or one fitted without setting blocks so it sits on the frame, can fail within a few years.
Stress from the frame
Over-tight glazing beads, a frame that has moved or a sash that's been slammed repeatedly can crack the seal at a corner.
| What you see | What it means | What to do |
|---|---|---|
| Fog that wipes off the room side | Normal condensation | Ventilate; see window condensation |
| Mist that comes and goes inside | Early seal failure | Plan a replacement unit |
| Permanent droplets or white marks inside | Seal failed, desiccant saturated | Replace the glass unit |
| Water pooling at the bottom of the frame | Blocked drainage | Clear weep holes; check other units |
| Crack in one pane | Unit broken, not just fogged | Replace the unit |
Can a fogged unit be fixed without replacing it?
Some services drill small holes in the glass, dry the cavity and plug the holes. The look can improve, but the edge seal is still broken, the insulating benefit is largely gone, and the haze often returns. Toughened panes can't be drilled at all. In most cases, replacing the sealed unit is the honest answer, and the frame and hardware can stay.
Checks you can do
- Wipe both faces to confirm the mist is between the panes.
- Check how many windows are affected; a cluster on one side of the flat points to sun or drainage.
- Look at the frame's bottom track for blocked drainage slots.
- Note whether any spacer bar marking is visible; it may show the unit's thickness or maker.
How it's replaced and quoted
Unit replacement is quoted from photos on WhatsApp, with no paid visit: send a photo of the fogged pane, the frame from inside, and the visible glass size, plus the floor. A new unit is made to the measured size and build-up (pane thickness and cavity), then fitted into the existing frame with fresh setting blocks and gaskets. The plain glass replacement service covers it.
If the frames themselves are failing, compare uPVC windows and the aluminium sliding window; our soundproof windows guide explains the glass build-ups.
Making replacement units last
- Keep frame drainage slots clear, especially before the monsoon.
- Don't let curtains trap heat against glass in direct sun.
- Avoid slamming sashes; it stresses the unit's corners.
For a cracked pane rather than a fogged one, see cracked window glass; noisy or dusty gaps are in window gap, dust and noise. Every glass fix is in the glass repair catalogue. Flats along the city's eastern expressway can see Noida Expressway. Send a photo of the fogged window on WhatsApp to start.
Common questions
Why is there fog between my double-glazed window panes?
The sealed unit's edge seal has failed. Humid air has got into the cavity, the moisture-absorbing spacer is saturated, and water condenses on the inside faces of the glass. It won't go away on its own, and it can't be wiped from outside.
Can I fix a foggy double-glazed window myself?
Not reliably. Drilling and drying the cavity can improve the look, but the seal is still broken and the haze usually returns. Toughened panes can't be drilled. Replacing the sealed glass unit in the existing frame is the lasting fix.
Do I need to replace the whole window if the glass is fogged?
Usually not. If the frame, sash and hardware are sound, only the sealed glass unit is replaced, made to the same size and build-up. The whole window is worth replacing only if the frame is also failing, leaking or warped.
Double glass window ke andar bhaap jam gayi hai, kya hoga?
The seal of the glass unit has failed, so moisture is trapped between the panes. Cleaning won't help. The glass unit is usually replaced and the frame kept. Send a photo and the glass size on WhatsApp and we'll tell you the options.
