Why is There Moisture on the Outside of My Window?

Windows | 8 June 2023
Outside Window Moisture

Have you ever woken up to find moisture on the outside of your window? The dedicated team from Adera Windows & Doors has encountered many cases where homeowners are perplexed by moisture on the outside of their window panes. It is understandable to question why there is moisture on the outside of your window, especially when most people believe that windows should be able to keep outdoor elements at bay. There are several reasons for moisture build up on windows, and understanding these causes can help you prevent this issue from occurring.

Learn more about four signs you need to replace your sliding glass door.

4 Reasons Why Moisture can Build Up on Widow Exteriors

1. Condensation

The cause of moisture buildup on windows is typically due to condensation. This occurs when warm, humid air comes into contact with cooler surfaces such as windows or glass doors. When this happens, the air cools down quickly and cannot hold onto its moisture, causing it to condense on the surface. This is especially common during the colder months, when people tend to keep their homes heated. This process is similar to when you take a cold drink from the fridge and notice water droplets forming outside the glass.

2. Humidity

One major factor is the relative humidity in your area. For example, relative humidity is typically at its lowest point during the summer when it is dry and hot; whereas, in the colder months, it tends to be much higher. This can lead to condensation forming outside windows as temperatures drop. When warm, moist air comes into contact with a cool surface, like a window, the moisture in the air condenses and forms droplets on the surface. This is why you often see moisture on windows during colder months when indoor heating systems run. To prevent this from happening, it is important to properly ventilate your home by using exhaust fans or opening windows when needed.

3. Temperature

You may see moisture on your windows due to sudden temperature changes. For instance, if there is a quick cold snap overnight and temperatures fall drastically, this can cause the air temperature to shift significantly. As a result, there will be less moisture in the air—since cold air cannot hold as much water vapour—which could cause dew or frost to form on the glass surface.

4. High-Performance Glass

In recent years, high-performance glass has become increasingly popular in homes and buildings thanks to its energy-efficiency benefits; however, this type of glass can exacerbate issues with condensation due to its ability to retain heat inside the building. If your home has triple Low-E or other high-performance windows installed, moisture on the exterior may be more noticeable than before. Unfortunately, because high-performance glass does not warm up your window’s outside pane as standard Low-E argon or older dual-pane units do, it can lead to extended freezing until warmer weather arrives and relative humidity drops.

If you want to know more about the reason for moisture on the exterior of your window, get in touch with Adera Windows & Doors team. You can contact us through our online form or call us at 833-652-5922. Our specialists can provide answers to your inquiries and suggest customized solutions.


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