How to stop condensation on windows
Few things are more frustrating than waking to mist-covered windows or discovering damp patches around your frames. Window condensation is more than an annoyance—it signals moisture accumulating indoors and can lead to mold, rot and damage. The good news? With the right habits and upgrades, you can keep it in check.
What causes condensation on windows?
When warm, moisture-rich air inside your home meets a cold glass surface, it cools down and the moisture condenses into water droplets. The main culprits are: a large temperature difference between interior and exterior, raised indoor humidity (from drying clothes, showers, cooking), poor ventilation so that moist air lingers, and inefficient windows (single-glazed or poorly insulated) that allow the inner pane to become very cool.
Daily habits that help
Start with basic steps. Each day, allow fresh air in for 10–15 minutes by opening windows or using trickle vents. Run extractor fans during and after showers or cooking, for about 15-20 minutes. Avoid drying clothes on radiators and maintain a consistent temperature—ideally around 18–21 °C. Move furniture a few centimetres away from external walls and windows so that air can destroy. If you spot condensation forming, wipe it off promptly to prevent mold or damage to frames.
Weekly / monitoring tasks
Keep an eye on indoor humidity using a hygrometer; aim for 30 %–50 %. If you're consistently above that, you're at higher risk of condensation forming. Check your windows and frames for signs of cold spots, peeling paint, bubbling or fog between double-glazed panes (which may signal a failed seal). Keep curtains open during the day to allow sunlight to warm the glass.
Long-term upgrades & insulation
If you're still struggling condensation despite good habits, then insulation and window upgrades come into play. Replace single-glazing with double or triple glazing (ideally with low-E coatings and argon fills) so that the inner glass stays warmer. Seal drafts around frames and doors. Use thermal blinds or insulated curtains to reduce cold surfaces. In rooms with chronic issues, consider using a dehumidifier, especially in winter, to remove excess moisture from the air.
Practical summary & takeaway
In essence, the trio of ventilation, moisture control, and surface-temperature management forms the backbone of preventing window condensation. Ventilate regularly, reduce the sources of humidity (drying indoors, excessive plants/aquariums, cooking without extractor use), and ensure your windows and room surfaces aren't overly cold. If the condensation you're seeing is between the panes of double glazing, it's probably a seal failure and the unit will need replacement rather than just cleaning.
By making these adjustments you'll help protect your home and its finishings, maintain healthier air quality, reduce the risk of mold, and avoid the frustration of waking to dripping windows.