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Window Condensation: Understanding What It Means

Window Condensation: Understanding What It Means

It’s almost that time of year where energy efficient windows can affect your heating bill by holding more temperate air in your house while resisting the elements outside. However, you may start to find condensation gathering on your windows and doors during colder months.

If you see condensation on your window, don’t stress! It isn’t time to start diagnosing your window. In fact, condensation on the inside of your windows—known as roomside condensation—isn’t a sign of a defective window at all. Rather, it means your windows are doing their job.

So, what is leading to the condensation on your windows? And, more importantly, what kind of condensation should make you concerned about your window’s health? Here are the facts about window condensation:

Do my new windows or doors lead to condensation?
Some homeowners connect the signs of condensation in the months after installing new windows with unnoticed problems during the installation process. Condensation on windows and doors is not created by the window or door product. Rather, it comes due to high humidity levels in your home.

As a matter of fact, the sight of condensation more often than not is an indication of the increased energy efficiency of your new windows. Air with more humidity holds water vapor until it touches a surface temperature less than or equal to the dew point—the temperature at which air becomes saturated and produces dew. Since glass surfaces are often the coldest part of the house, condensation appears on windows first, in the presence of water droplets or frost on the roomside of the house’s window. As the air inside becomes drier, or as the glass surface becomes warmer, condensation begins to dissipate.

Many factors go into whether you might find condensation on your windows. You might even discover that a window in one part of your room has roomside condensation while another in the same room doesn’t. Air circulation, varying room temperatures, air register location, and the type and size of the window can all impact the likelihood of roomside condensation. Other factors like glass type, window coverings and screens and proximity to a water source can all determine what levels of humidity can be noticed around a window.

Why do I sometimes see condensation on opposite sides of the window?
Your previous windows may have been drafty or didn’t feature the advanced, energy efficient elements of modern windows. Additionally, other home repairs, such as building a new roof or siding, might also build a tighter seal against air infiltration in your home. As a result, your home may hold more humidity making condensation more likely to happen than before.

In the heat, this same phenomenon can be observed on the outside of your windows. Exterior condensation can gather as a result of high outdoor humidity, little or no wind, and a clear night sky. It establishes itself in the same way as roomside condensation, when the temperature of the glass cools below the dew point of the outside air. Since the cooler air inside your home isn’t leaking due to increased energy efficiency, it’s more likely to see external condensation at times like these.

You can address exterior condensation by opening curtains at night to warm up exterior glass and increase air circulation by cutting back any plants that might be interfering with windows. Setting the air conditioner a few degrees warmer can also make a difference.

For roomside condensation, there are a number of factors that can influence the humidity in your house. Here are a few common culprits that can lead to roomside condensation:

Sources of humidity in your home 

The most commonly seen way roomside humidity increases is through everyday home activities. Running showers and baths, cooking and washing dishes, doing laundry, even the dog’s water bowl can all bring moisture to the air in your home–topping out at four gallons or more per day in some homes. Factor in today’s energy efficient, well-insulated homes and you can start to see why that humidity can often find no way to escape.

Because of this better insulation, some windows can develop a strip of condensation that forms all the way around the roomside of the window. Most often, this happens when the center of the glass stays warmer than the glass closest to the edge. It isn’t a sign that the window is leaking air or not functioning correctly.

Can Roomside Condensation Ruin My Windows?
One instance where condensation on windows should become an immediate concern, however, is if condensation is seen between the two sealed panes of insulating glass in multi-pane windows. In this instance, condensation is a sign of seal failure and the insulating glass must be replaced.

More often than not though, condensation on your windows doesn’t mean there is a defect with your windows. It serves as an alert to the possibility of other unnoticed, potentially pricey problems to be found in your home.

igh indoor humidity can lead to structural damage and even upset your health. Because these effects frequently go without notice in the wall cavities, attics and crawl spaces, the visible presence of condensation on glass is a good signal that humidity levels are too high. And while window condensation and musty odors might be seen as annoyances, they can develop into more immediate concerns such as water stains on walls and ceilings if left alone.

In the same way, left unaddressed, condensation issues can mean window problems over time. Make sure to take chronic roomside condensation seriously. Think of it as an early warning to high humidity in your home, one that can easily be resolved before it gets worse. Understanding condensation is just the beginning to keeping your home comfy and maintaining your windows. If you have any questions about condensation and whether your windows and doors are working effectively, give Pella Windows and Doors in Wellesley a call or stop by the showroom.

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