Condensation on windows can be a nuisance to homeowners across the country, especially during the colder months. There’s good news though: It’s almost always possible to avoid these potential moisture-related issues, as well as fix existing ones…
As you probably know, window condensation occurs when the warm, moist air comes into contact with the cold surface. This temperature difference causes the warm air to cool down and release its moisture, leading to the formation of water droplets.
It can be a sign of poor ventilation, potentially leading to mould and mildew growth, not to mention other moisture-related problems in your home.

So what exactly are the different causes of window condensation?
We’ll look at prevention tips and discuss potential solutions to help you understand and manage this common issue, ultimately enhancing your overall home comfort and well-being.
Causes of Window Condensation
Before fixing the issue of condensation on windows, it’s important to know what’s causing your problem. There are a few possibilities…
Temperature Differences
Window condensation occurs when warm, moist indoor air comes into contact with a cooler surface, such as a windowpane. This is because glass is one of the least heat-resistant materials in a building, allowing the cold outside temperature to influence the indoor environment.
When the warm air meets the cold surface, it cools and releases moisture in the form of condensation. This phenomenon is more apparent during winter months or in climates with a significant temperature difference between day and night.
High Indoor Humidity
Another factor contributing to window condensation is high indoor humidity levels. The amount of moisture in the air directly correlates to the likelihood of condensation forming on windows. The most common reasons for condensation in your home are:
- Cooking, especially boiling water or simmering foods
- Bathing or showering with inadequate ventilation
- Humidifiers, without proper monitoring of humidity levels
- Drying laundry indoors without ventilation
It is essential to monitor and manage the humidity levels in your home to prevent condensation. Investing in an inexpensive hygrometer can help you track indoor humidity and take necessary steps to reduce it if needed.
Inadequate Ventilation
Inadequate ventilation is a common cause of window condensation. Homes that lack proper air circulation can trap moisture, leading to higher indoor humidity levels. Some contributing factors to poor ventilation include:
- Insufficient or blocked vents
- Poorly designed or obstructed air ducts
- Sealed-off fireplaces or unused rooms
Improving the ventilation within your home can significantly reduce window condensation by allowing the moist air to escape. Ensuring that fresh, dry air circulates throughout your living space will achieve great results.
Conscientious homeowners will benefit from installing vents, exhaust fans, or air exchange systems, as well as opening windows when weather permits.
Preventing Or Fixing Window Condensation
Reducing Indoor Humidity
One of the primary causes of window condensation is high indoor humidity levels. To prevent condensation on windows, try to reduce indoor humidity by:
- Running a dehumidifier in areas with high humidity.
- Utilising exhaust fans in bathrooms and kitchens.
- Limiting the use of humidifiers or adjusting their settings to maintain a balanced indoor humidity level.
- Ventilating your home properly by opening windows for short periods.
A note on Dehumidifiers
A dehumidifier can help manage indoor humidity levels and thereby reduce condensation on windows. Place one in rooms with high levels of moisture, like bathrooms or kitchens.
When choosing a dehumidifier you’ll need to consider the room’s size and desired humidity level. Monitor the humidity using an inexpensive hygrometer. Aiming to keep indoor humidity between 30% and 50% is the best way to see a reduction in condensation.
A note on Proper Ventilation Systems
Ensuring proper ventilation can improve air circulation and reduce condensation. Here are some tips to follow:
- Ensure that vents, air ducts, and exhaust fans are clean and unblocked.
- Open windows or use exhaust fans during activities that generate moisture, like cooking or showering.
Improving Air Circulation
Proper air circulation can also help prevent window condensation. To improve air circulation in your home, you can:
- Place fans strategically to enhance the movement of air.
- Avoid overcrowding furniture, which can obstruct airflow.
- Regularly clean and replace air filters in your heating and cooling system.
Insulating Glass Windows
Poorly insulated windows can contribute to condensation problems by making surfaces cold, on which moisture can condense. To insulate glass windows effectively:
- Install double-pane or triple-glazed windows, which can limit the transfer of cold air into the home.
- Utilize window film or insulating curtains to provide a barrier between windows and indoor air.
- Consider replacing older windows with energy-efficient options.
Installing Storm Windows
Storm windows provide an additional barrier between your home’s interior and the cold outdoor air. Installing storm windows can help to:
- Reduce heat loss through windows, which makes surfaces warmer and less likely to attract condensation.
- Increase overall energy efficiency of your home, reducing both heating costs and condensation issues.
Condensation-Resistant Windows
Opting for condensation-resistant windows is one way to mitigate the problem. These windows include double or triple-paned glass units with insulating gas in between the panes. This reduces temperature differences between the indoor and outdoor surfaces, which will limit the amount of condensation you experience. Look for windows with a high Condensation Resistance (CR) value for best results.
Window Film Installation
Installing window film, also known as insulating film or low-emissivity film, on the window glass can help in reducing condensation.
Window films are designed to improve insulation and reduce heat transfer through the glass which will decrease condensation. Be sure to hire a professional for proper installation and best results.
Recap: Beating Condensation on Windows for Good

Although window condensation is just a chemical reaction, it’s a frustrating and common issue faced by many homeowners. It’s good to know there are strategies you can implement to help the situation.
By understanding the causes of window condensation, it’s possible to put preventative measures and solutions in place, to address this issue.
If you can improve ventilation in your home and reduce humidity, you’re off to a good start. If that’s not enough then you may wish to check out the insulation of your windows, making sure they are working effectively – an upgrade may be necessary.
How you choose to respond to the problem of condensation, really can make a difference. The remedy is out there and will completely transform your home into a more comfortable living space