How to Stop Condensation on Windows: Practical Solutions for Your Home

Struggling with misty windows and damp corners? Excess condensation isn’t just a nuisance, it can damage your interiors and encourage mould growth. Condensation on windows might seem like a minor annoyance, but if left untreated, it can lead to serious problems—like mould growth, rotting frames, and poor indoor air quality.

Whether you’ve noticed damp patches around your sills or just want a healthier home environment, this guide breaks down how to deal with window condensation, prevent mould, and improve ventilation in your home. Discover smart, practical ways to cut down moisture, boost airflow, and keep your windows clear and dry with expert advice from Painter Adam.

What Causes Condensation on Windows?

Condensation occurs when warm, moist air hits a cold surface—like your windows. It’s most common in winter when we keep homes sealed up to retain heat.

Common sources of indoor moisture:

• Cooking and boiling water

• Showering

• Drying clothes indoors

• Breathing and general living

When this moisture can’t escape, it settles on the coldest surfaces—often windows.

This condensation is a major problem:

• It damages window sills, frames, and paintwork

• Creates a perfect breeding ground for mould and mildew

• Worsens asthma and allergies

• Reduces insulation effectiveness

How to Stop Condensation on Windows

It is important to curb condensation and reduce window moisture in order to prevent mould and mildew growth on your windows. Here are some steps you could follow:

1. Wipe Down Windows Daily

Use a microfibre cloth, towel, or window vac each morning to remove excess moisture. Don’t let moisture sit—regular pooling can rot timber frames and damage plaster.

2. Ventilate Key Rooms

Open trickle vents as these small vents at the top of window frames allow air circulation even when the windows are shut. Crack windows open regularly, especially:

• In the morning after waking up

• After cooking or showering

• When drying clothes indoors

Use extractor fans, especially the bathroom and kitchen fans while using those rooms and leave them on for 10–15 minutes afterward.

3. Use a Dehumidifier

A compact dehumidifier can pull litres of moisture from the air daily. Place it near windows or in damp-prone rooms. This is an ideal window care solution for bedrooms, basements, or homes without adequate natural airflow.

4. Control Indoor Humidity

Try to keep humidity between 40% and 60%. You can check it using a hygrometer (a small device that measures humidity). To reduce humidity, you can:

• Use lids when boiling water.

• Avoid drying clothes indoors when possible.

• Vent tumble dryers properly.

5. Insulate and Double-Glaze

Cold surfaces attract condensation. You can keep your windows warmer by:

• Double- or triple-glazing adds insulation and reduces condensation risk.

• Thermal curtains or window film can also help, especially on older windows.

6. Improve Whole-House Ventilation

If your home still struggles with condensation on windows, you may need broader solutions:

• Positive Input Ventilation (PIV) systems – Draw fresh, filtered air into the house and push out stale, moist air.

• Heat Recovery Ventilation (HRV) – Balances air quality and energy efficiency by recycling warm air while ventilating.

• Air bricks or wall vents – Passive systems that improve airflow in key areas.

How to Prevent Mould on Windows

Condensation left untreated leads to mould—and that’s when things get serious.

Signs of Mould Growth:

• Black or dark green spotting on window frames or sills

• Musty smell

• Discolouration on plaster or paint

Prevention Steps:

• Follow all condensation reduction tips above

• Regularly clean window sills and frames with anti-fungal cleaner

• Treat any black mould patches early with vinegar or a mould-removal spray

For Wooden Windows:

• Sand back mould-damaged paint

• Prime and repaint with mould-resistant paint

• Keep the wood sealed and dry

Ventilation Tips for a Healthier Home

1. Don’t block air bricks or vents. These are essential for background airflow.

2. Leave interior doors slightly open, especially in winter, to equalise temperature and humidity across rooms.

3. Open windows diagonally (one on each side of the house) for cross-ventilation.

4. Add a bathroom extractor timer – Fans should keep running after you shower, not switch off the moment you flick the light off.

5. Consider installing a PIV system if your home has chronic damp, especially in older or sealed-up properties.

Bonus Tips for Irish Homes

Ireland’s damp climate makes condensation and mould even more common. Here’s what you can do specifically:

1. Use breathable paints on walls and sills to allow moisture to escape.

2. Maintain gutters and exterior drainage. Leaks or overflows near windows can worsen internal damp.

3. Inspect attic insulation and airflow. Poor ventilation upstairs can trap warm, moist air below.

4. Keep heating consistent. Short bursts of heat create humidity spikes. A steady, lower temperature is better for moisture control.

The Final Word

Condensation is more than just foggy windows—it's a sign your home is holding too much moisture. But with simple daily habits, proper ventilation, and the right tools, you can take control of your indoor environment, protect your windows, and prevent mould before it starts.

Need help with damp or interior repainting after mould damage? At Painter Adam, we are here to offer professional advice and window care solutions for homes across Ireland. You can get a free estimate for your project right now, or get in touch with us today for a home consultation.