Condensation on windows in winter is far more common than you might expect, and a lot of homeowners have to deal with it. What starts as a minor nuisance can quickly escalate into a major problem, potentially damaging your windows and leading to mold growth. If you’re reading this article, chances are you’re already dealing with this issue and looking for effective solutions, right?
In essence, condensation on windows in winter forms when warm, moisture-laden indoor air meets the cold glass surface, forming water droplets. Curious to learn exactly why this happens and how to stop it for good? Keep reading to discover the causes and the best strategies to prevent it!
Key Takeaways
- Interior window condensation forms in winter when the indoor air temperature is higher than the window surface temperature. This often occurs when the windows are poorly insulated or when indoor humidity levels exceed 60%.
- You can reduce condensation on interior glass surfaces by replacing your windows with energy-efficient units. If your windows are already energy-efficient, your goal is to reduce indoor humidity. Use dehumidifiers, ventilate your house frequently, use exhaust fans and ceiling fans, and make sure to wipe down your windows every time you notice condensation. You can minimize drafts by replacing old caulk and installing weatherstripping.
- If you notice condensation on exterior windows in winter, you have nothing to worry about – this means your windows are insulated as needed.
- If you have double-pane windows and notice condensation between the glass panes, the window seal is likely broken, and you’ll have to replace the windows.
What Causes Window Condensation in Winter?
When the warm, humid air inside your home meets the cold surface of your windows, condensation forms. Have you ever noticed how the surface of a glass taken out of the fridge on a hot summer day fogs up? It’s exactly the same process that causes condensation on windows in winter. Warm, humid air is attracted to cold surfaces (in this case, the window frame and glass), which is why condensation appears on them first.
As such, this phenomenon is especially common in winter because of the significant difference between the temperatures inside and outside your home. Plus, as mentioned earlier, it isn’t enough for the indoor air temperature to be higher than the window surface temperature – it also needs to be humid. When the air is humid, condensation forms much more quickly. When the air is dry, the difference between air temperature and surface temperature must be much more significant for condensation to form on that surface.
What Causes Interior Window Condensation in Winter?
Interior condensation on windows, especially in winter, is often caused by poorly insulated windows. The more energy-efficient a window is, the warmer its interior surface. Why? Easy! Let’s say we’re talking about a double-glazed window whose glass panes are separated by inert gas and other insulating materials. The role of these insulating materials is to prevent the cold outdoor air from entering the house. It acts as a barrier. Therefore, the interior glass surface of a well-insulated window will always be much warmer than the exterior glass surface.
Therefore, if you have double-glazed windows and condensation forms on them regularly, they may be poorly insulated. If you have single-glazed windows – the condensation is definitely caused by poor insulation because there’s no barrier to stop the interior glass surface from becoming cold.
However, sometimes even the most energy-efficient windows fog up on the inside. There are several factors that contribute to this, primarily linked to excessive moisture:
- Routine activities such as cooking, showering, and even breathing release moisture into the air.
- Aquariums and houseplants also add to the humidity levels inside your home.
- Poor ventilation further exacerbates the problem by trapping this moisture indoors.
- Heavy window treatments can also limit air circulation around your windows, increasing the likelihood of condensation forming.
- Drying your clothes inside the house can significantly increase indoor humidity levels.
How Do You Stop Condensation on Windows in the Winter?
Now that we’ve established what exactly causes condensation on windows in winter, let’s see how we can address this issue!
1. Replace Your Windows with Energy-Efficient Options
If you suspect that the culprit of regular condensation is the lack of energy efficiency, it may be time to replace your windows. It is undoubtedly a significant investment but absolutely worth it in the long run.
First, any other methods to prevent condensation will only be temporary, and some may not even work. Secondly, investing in energy-efficient windows can lower your energy bills and help you save money over the years. Thirdly, well-insulated windows will keep your home warm in winter and cool in summer, enhancing your comfort. Last but not least, high-quality windows significantly increase property value, which is an enormous advantage in case you ever decide to sell your house.
As such, if you need to replace your windows, you can consider Magic units, which are designed based on Canadian weather, thus being incredibly energy-efficient. Here’s why our windows and doors take the lead in the industry:
- Our frames consist of vinyl, aluminum, and steel. This means they’ll last 40 years (and more!) and won’t warp or crack in extreme weather conditions.
- We use the best-performing warm-edge spacers.
- The gap between the two glass panes within our Insulated Glass Units (IGUs) is larger than the gap in standard windows. This means we can add more inert gas between the glass panes, which significantly improves energy efficiency.
- You also have the possibility to install fully retractable thermal blinds, which boost a window’s energy efficiency by 40%.
2. Use a Dehumidifier
If your windows are energy-efficient, the problem is likely high indoor humidity. Therefore, it’s the first thing you should address, and you can do so by purchasing a dehumidifier.
Invest in a high-quality product that will effectively reduce indoor humidity levels. Plus, make sure to check the area it covers – you may have to buy more dehumidifiers if your house is large. Additionally, consider purchasing a dehumidifier with an incorporated humidity meter, as it will be much easier to monitor relative humidity this way – it’s best to keep indoor humidity below 60% at all times.
3. Prevent High Humidity Indoors
Here are some tips that can help you avoid running the dehumidifier non-stop:
- Keep the lid on the pot when you’re cooking.
- Maintain steady indoor temperatures
- Open your windows every day, several times a day, to ventilate the house (but don’t forget that the outdoor air may be humid as well!).
- Avoid drying your clothes in the house. If you do have to dry them indoors, you can purchase a dehumidifier with a “drying” option, which allows it to work at maximum capacity to dry the clothes faster.
- Run the dehumidifier immediately after taking a shower or open your bathroom window if there is one.
- Regularly open and close window curtains to avoid moisture accumulation around the windows, which can lead to mold growth.
- Remove some plants, as they can increase indoor humidity.
- Use ceiling fans – they are particularly effective as they push warm air throughout the room, ensuring that no spot becomes too humid.
- Run exhaust fans in the kitchen and bathroom, as it will help remove the moist air accumulated during cooking and showering. You can install timers on your exhaust fans to ensure they run for the necessary duration, typically about 15 to 20 minutes.
- Run a dehumidifier in the basement, as there’s often more humidity there, which can escape into the house.
- Check for any plumbing leaks or drainage problems around the house that can cause high humidity.
4. Seal and Insulate Your Windows
In some cases, the interior surface of your windows gets cold because there may be some tiny gaps or cracks around them through which cold outdoor air seeps into the house. In this case, you may be able to solve the problem without replacing your windows. For example, you can replace the old caulk and fill any gaps around the windows. You can also replace the weatherstripping.
Additionally, if you can’t replace your existing windows with more energy-efficient units, you can insulate them for the winter yourself. You can buy a specialized window insulation kit. Other solutions include applying bubble wrap, installing thermal curtains, sealing cracks with rope caulk, applying spray foam, using draft stoppers, or installing window inserts.
Don’t forget to pay close attention to your bay and bow windows. Since they protrude outwards from the main building wall and are usually a few degrees colder, they can be more prone to condensation. Make sure to insulate that area accordingly.
5. Wipe Down Your Windows When Condensation Forms
When you do notice condensation on your windows, make sure to wipe them down as soon as possible. Otherwise, the water droplets may damage your window frame and sill, as well as the surrounding structures.
Over time, this can create the perfect environment for mold growth, which, in turn, can affect your health and lead to costly repairs.
Exterior Window Condensation – What Causes It?
Exterior window condensation is nothing to worry about – it is an indicator that your windows are energy-efficient and insulated properly. It confirms that the exterior glass surface remains cold and the warm interior air doesn’t escape through the windows.
Exterior condensation often forms early in the morning after a cool night, especially when outdoor humidity is high, there is little wind, and the sky is clear. It’s the same phenomenon described above – the glass surface temperature is lower than the air temperature, and the air is humid; thus, the warm, moist outdoor air comes into contact with the colder glass surface, and condensation forms. However, it usually disappears when the sun warms up the glass surface, so it shouldn’t cause any issues.
Condensation Between Window Panes – Can You Fix It?
During the winter, condensation between the window panes may become more evident. Unfortunately, this is a sign that the insulated glass unit’s seal has failed, and air and moisture seep in, remaining trapped between the two glass panes. This not only diminishes the window’s insulating properties but also affects the comfort levels in your home and increases energy bills.
In most cases, condensation between two glass panes is a clear indicator that you’ll need to replace your windows. However, you may be able to replace only the panes if the window frame is in good shape. This may be a good solution if you’re on a tight budget.
Maintenance Tips to Prevent Window Damage and Condensation
Regular maintenance keeps your windows functional and energy efficient. By checking your windows once in a while and maintaining them properly, you keep condensation at bay and make sure your home is as comfortable as it can get!
This involves checking for drafts, replacing old caulk regularly, and checking and lubricating (and replacing if needed) window hardware. If you notice any damage, address it as soon as possible. Plus, if you see any cracks in the glass, you have to replace it right away – you may still be able to keep the window frame if it’s in good shape.
Contact Magic for the Best Replacement Windows in the GTA!
If you’re willing to replace your windows with more energy-efficient options, don’t miss out on the opportunity to install the best replacement windows in the GTA, which will perform at their best for 40 years!
Magic has brought glass production in-house, which is why we have the possibility to manufacture windows designed particularly for Canadian weather and its fluctuating temperatures. Our window units can withstand the harshest weather conditions, keeping your house comfortable and lowering your energy bills year-round!
Frequently Asked Questions
Is condensation normal on windows in winter?
If indoor humidity is high, it is only natural to have condensation on windows in winter. However, if you lower indoor humidity and there’s still condensation, your windows are likely poorly insulated, and you’ll have to replace them.
Does condensation on windows mean poor insulation?
If indoor humidity levels are low, condensation on windows is likely an indicator of poor insulation. If you have single-glazed windows or old double-glazed windows, you may have to replace them.
How to stop condensation on windows overnight?
To stop condensation on windows overnight, ensure that the indoor temperature remains steady overnight, reduce humidity levels, and leave the windows slightly open if possible.
Why does window condensation occur more frequently in winter?
Window condensation occurs more frequently in winter because of the significant temperature difference between warm indoor air and cold outdoor air. When the warm indoor air comes into contact with the colder window surfaces, it cools down, and the moisture in the air condenses into water droplets. This happens because cooler air cannot “hold” as much moisture as warmer air.
When should I consider professional help for window condensation issues?
Consider seeking professional help when you see persistent condensation between window panes or if flooding occurs, as these issues often signal underlying moisture problems that need expert attention.