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Window Condensation: Understanding What It Means

Window Condensation: Understanding What It Means

It’s almost that season where energy efficient windows can impact your heating costs by retaining more temperate air in your home while defending against the elements outside. However, you may start to see condensation gathering on your windows and doors during colder months.

If you find condensation on your window, don’t worry! It isn’t time to start investigating your window. The fact is, condensation on the inside of your windows—known as roomside condensation—isn’t a sign of a defective window at all. Just the opposite, it means your windows are working well.

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

Do my new windows or doors cause condensation?
Some homeowners pair the sight of condensation in the months after installing new windows with unnoticed problems during the installation process. Condensation on windows and doors is not produced by the window or door product. Rather, it comes as a result of high humidity levels in your house.

As it turns out, the presence of condensation more often than not is an indication of the better energy efficiency of your new windows. Air with high 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 usually the coldest part of the room, condensation can be seen on windows initially, in the indication of water droplets or frost on the roomside of your window. As the air inside gets drier, or as the glass surface heats up, condensation begins to disappear.

Many factors go into whether you might see condensation on your windows. You might even notice that a window in one part of your room has roomside condensation while one on the other side doesn’t. Air circulation, changing room temperatures, air register location, and the type and size of the window can all impact the chances of roomside condensation. Other factors like glass type, window coverings and screens and proximity to a water source can all have an impact on what levels of humidity appear around a window.

Why do I at times see condensation on opposite sides of the window?
Your previous windows could have been drafty or didn’t include the advanced, energy efficient components of modern windows. But, other home repairs, such as building a new roof or siding, might also create a tighter seal against air infiltration in your room. Because of that, your home may keep more humidity making condensation more likely to be seen than before.

In the summer months, this same phenomenon can be noticed on the outside of your windows. Exterior condensation can gather because of high outdoor humidity, little or no wind, and a clear night sky. It grows in the same way as roomside condensation, when the temperature of the glass drops below the dew point of the outside air. Since the cooler air inside your house isn’t escaping due to increased energy efficiency, it’s more likely to see external condensation at these times.

You can manage exterior condensation by opening shades at night to warm up exterior glass and increase air circulation by trimming any shrubbery that might be blocking windows. Programming the air conditioner a few degrees warmer can also make a difference.

For roomside condensation, there are a few factors that can influence the humidity in your room. Here are a couple of common culprits that can create roomside condensation:

Sources of humidity in your home 

The most commonly seen way roomside humidity increases is through everyday living. Heat and moisture from showers and baths, cooking and washing dishes, doing laundry, even the dog’s water bowl can all add moisture to the air in your home–up to four gallons or more per day in some homes. Include 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 shows up 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 warning that the window is leaking air or not functioning correctly.

Can Roomside Condensation Hurt My Windows?
One instance where condensation on windows should become an immediate warning, however, is if condensation is noticed between the two sealed panes of insulating glass in multi-pane windows. In this case, condensation is a sign of seal failure and the insulating glass will need to be replaced.

More likely though, condensation on your windows doesn’t mean there is a concern with your windows. It serves as a sign to the possibility of other unnoticed, potentially pricey problems in other areas in your house.

High indoor humidity can eventually cause structural damage and even upset your health. Because these effects frequently go unseen in the wall cavities, attics and crawl spaces, the visible indication of condensation on glass is a good sign that humidity levels are too high. And while window condensation and musty odors might be seen as bothersome, they can evolve into more immediate concerns such as water stains on walls and ceilings if left unresolved.

In the same way, left unaddressed, condensation issues can lead to window problems over time. Make sure to take continual roomside condensation seriously. Think of it as an early alarm to high humidity in your room, one that can easily be solved before it gets more severe. Understanding condensation is just the beginning to keeping your home comfortable and maintaining your windows. If you have any questions about condensation and whether your windows and doors are resisting condensation properly, give Pella Windows and Doors in Grand Rapids a call or come into the showroom.

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