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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 improve your heating bill by holding more temperate air in your house while defending against the elements outside. However, you may start to find condensation gathering on your windows and doors during colder months.

If you find condensation on your window, don’t panic! It isn’t time to start looking for something wrong with your window. As a matter of 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 causing the condensation on your windows? And, more importantly, what kind of condensation should raise alarms about your window’s health? Here are the facts about window condensation:

Do my new windows or doors create condensation?
Some homeowners connect the sight of condensation in the months after installing new windows with possible problems during the installation process. Condensation on windows and doors is not caused by the window or door product. Instead, it comes due to high humidity levels in your house.

As it turns out, the presence of condensation more often than not is an indication of the increased energy efficiency of your new windows. Air with increased humidity keeps 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. Due to the fact that glass surfaces are most likely the coldest part of the home, condensation shows up on windows more frequently, in the presence of water droplets or frost on the roomside of the window. As the air inside becomes drier, or as the glass surface warms, condensation begins to disappear.

Many factors go into whether you might see condensation on your windows. You might even find that a window in one part of your room has roomside condensation while a different one doesn’t. Air circulation, varying room temperatures, air register location, and the type and size of the window can all impact the presence of roomside condensation. Even the glass type, window coverings and screens and proximity to a water source can all play a role in what levels of humidity can be noticed 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 today’s windows. However, other home repairs, such as adding a new roof or siding, might also create a tighter seal against air infiltration in your room. Due to that, your home may hold more humidity making condensation more likely to happen than before.

In the summer months, this same phenomenon can be seen on the outside of your windows. Exterior condensation can appear 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 cools below the dew point of the outside air. Since the cooler air inside your house isn’t leaking due to increased energy efficiency, it’s more likely to see external condensation at times like these.

You can manage exterior condensation by opening curtains at night to warm up exterior glass and increase air circulation by removing any shrubbery that might be interfering with windows. Setting the air conditioner a few degrees warmer can also improve the situation.

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

Sources of humidity in your home 

The most common way roomside humidity increases is through everyday living. Taking showers and baths, cooking and washing dishes, doing laundry, even the dog’s water bowl can all increase moisture to the air in your home–as much as four gallons or more per day in some homes. Factor in today’s energy efficient, well-insulated homes and you can start to understand why that humidity can often find no path to escape.

As a result 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 sign that the window is leaking air or not functioning correctly.

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

More often than not though, condensation on your windows doesn’t mean there is a concern with your windows. It serves as an indicator to the possibility of other unseen, potentially costly problems elsewhere in your room.

High indoor humidity can result in structural damage and even impact your health. Because these effects frequently go unnoticed in the wall cavities, attics and crawl spaces, the visible indication 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 grow into more severe concerns such as water stains on walls and ceilings if left unchecked.

In the same way, left unaddressed, condensation issues can cause window problems over time. Make sure to take continual roomside condensation seriously. Think of it as an early warning to high humidity in your room, one that can easily be solved before it gets serious. 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 working properly, give Pella Windows and Doors in Natick a call or come into the showroom.

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