Windows · Winter condensation

Window condensation in Gurgaon winters: why glass sweats and how to stop it

Condensation on the inside of a window is warm, humid room air meeting cold glass, and in Delhi NCR it peaks on December and January mornings. Better ventilation cures most of it; persistent streaming on single glass is solved with double-glazed units, and fog between two panes is a failed unit.

Updated 8 October 2026Gurugram & Noida

uPVC window with glass panes, viewed from inside a room

On a January morning in Gurugram or Noida, with the outside air at 5°C, many people find their bedroom windows streaming with water, a puddle in the track and black specks of mould starting in the corners. It looks like a leak, but the water came from inside the room.

The short answer

Air holds moisture as invisible vapour. When it touches a surface colder than its dew point, the vapour turns to droplets. Glass is the coldest surface in a winter room, so it sweats first. Less moisture in the room, more air movement, or a warmer inner glass surface stops it.

Is it a window problem or a room problem?

Where the water forms tells you.

Condensation: where it forms and what to do
Where the droplets are	What it means	What fixes it
Inside face of single glass	Normal physics: humid room, cold glass	Ventilation, dehumidifying, or double glazing
Inside face of double glazing, only at edges	Cold spacer bar or aluminium frame edge	Usually tolerable; warm-edge spacers help
Between the two panes of a double-glazed unit	The unit's seal has failed	Replace the sealed unit
Outside face, early morning	Cold, efficient glass on a humid night	Not a fault; it clears by mid-morning
On the aluminium frame itself	Uninsulated metal frame	Thermally broken or uPVC frame

Why NCR homes get it so badly

Sealed rooms and room heaters

Winter in Delhi NCR means windows shut against cold and smog, and often an oil heater or gas heater running for hours. Gas heaters in particular release water vapour as they burn. Breathing, cooking and drying clothes indoors add litres more each day.

Single glass in a light frame

Most older flats have 4–5mm single glass in aluminium sliding frames. Both conduct cold straight through, so the inner surface sits only a little warmer than outside.

Smog days keep everything shut

When the AQI is in the severe band, nobody opens a window, so the moisture has nowhere to go. That's exactly when condensation and mould get worse.

What you can do yourself

Run the kitchen and bathroom exhaust fans during and for twenty minutes after cooking and showers, and keep those doors shut.
Air the bedroom for ten minutes in the warmest part of the day, even in smog season, or run an air purifier with the door ajar to move air.
Dry clothes on the balcony or in a ventilated utility area, not in the bedroom.
Wipe the glass and track each morning and empty the water before it soaks the sill. Clean any black spots with a mild bleach solution.
Pull heavy curtains a few centimetres back from the glass at night so warm room air can reach it.

When the windows themselves need changing

If you have done all of the above and single-glazed windows still stream every morning, the glass is the problem. Double-glazed units put an air or gas gap between two panes, so the inner pane stays near room temperature and stops sweating, and they also cut road noise. They need a frame that can carry them: a uPVC window or a heavier aluminium sliding window section. If you see mist trapped between two panes rather than on the room side, read double-glazed window fogged, because that sealed unit has failed. The uPVC window price guide explains what affects the cost of an upgrade.

How FabWise helps

Send photos of the glass in the morning, showing which side the water is on, plus a photo of the frame. That tells us whether it's ventilation, the glass, or a failed sealed unit. If you want to upgrade, we visit for ₹99 (adjusted against the bill), measure, and quote the new windows in writing. We'll also tell you honestly when a fan and an open window will do.

Prevention through the year

Condensation is a winter problem, but mould from it lingers into spring. Re-check the silicone round the inside of the frame each March and clean the track drains so the season's water can escape. For smog-season comfort, our guide to soundproof windows in Delhi NCR covers sealed, double-glazed options. If rain rather than condensation is getting in, see balcony door leaking. Window work in Delhi itself is on windows and doors in Delhi.

Common questions

Why do my windows have water inside every morning in winter?

Warm, humid air in the room is meeting cold window glass and condensing. Sleeping with windows shut, running heaters and drying clothes indoors all add moisture. Ventilate daily, use exhaust fans and wipe the glass; if single glass still streams, double glazing solves it.

Is window condensation a sign the window is faulty?

Not usually. Droplets on the room side of single glass are normal physics. It's a fault when mist forms between the two panes of a double-glazed unit, which means the seal has failed, or when water seeps in at the frame during rain.

Do double-glazed windows stop condensation?

They greatly reduce it. The inner pane stays close to room temperature, so humid air rarely reaches its dew point. In a very humid room you may still see a little at the bottom edge on the coldest mornings, but the streaming stops.

Sardi mein khidki par paani kyun jamta hai?

Because the glass is colder than the room air, and moisture from breathing, cooking and heaters condenses on it. Open the window for a few minutes daily, use exhaust fans, and keep curtains slightly off the glass. Single glass that keeps sweating is best replaced with double glazing.

Can condensation damage my window frame?

Water pooling in the track every morning soaks the sill and wall below, causes mould on the seals and paint, and can corrode cheap steel screws in aluminium frames. Wipe it daily and keep the drainage holes clear until the cause is fixed.