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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 costs by keeping more temperate air in your home while keeping the elements outside. However, you may start to see condensation gathering on your windows and doors during colder months.

If you notice condensation on your window, don’t worry! It isn’t time to start looking for something wrong with 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. Instead, it means your windows are working well.

So, what is causing the condensation on your windows? And, more importantly, what signs of condensation should make you concerned about your window’s stability? 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 caused by the window or door product. Rather, it comes due to high humidity levels in your home.

As it turns out, the signs of condensation more often than not is an indication of the better energy efficiency of your new windows. Air with increased humidity retains water vapor until it comes into contact with a surface temperature less than or equal to the dew point—the temperature at which air becomes saturated and produces dew. Because glass surfaces are most likely the coldest part of the house, condensation appears on windows more frequently, in the form of water droplets or frost on the roomside of the window. As the air inside grows drier, or as the glass surface becomes warmer, condensation begins to lessen.

More than a few factors go into whether you might notice condensation on your windows. You might even find that a window in one part of your room has roomside condensation while one on the other side doesn’t. Air circulation, changes in room temperatures, air register location, and the type and size of the window can all increase 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 are 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 feature the advanced, energy efficient elements of present-day 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. As a result, your home may keep more humidity making condensation more likely to happen than before.

In the warmer seasons, this same phenomenon can be noticed on the outside of your windows. Exterior condensation can appear due to 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 leaving due to increased energy efficiency, it’s more likely to see external condensation at these times.

You can deal with exterior condensation by opening window coverings at night to warm up exterior glass and increase air circulation by removing any shrubbery that might be blocking windows. Programming the air conditioner a few degrees warmer can also help.

For roomside condensation, there are a few factors that can impact 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 frequent way roomside humidity increases is through everyday living. Running 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. Include today’s energy efficient, well-insulated homes and you can start to see why that humidity can often find no path to escape.

Because of this better insulation, some windows can build a strip of condensation that appears all the way around the roomside of the window. Usually, 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 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 case, condensation is a mark 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 defect with your windows. It serves as a sign to the possibility of other hidden, potentially expensive problems elsewhere in your home.

igh indoor humidity can result in structural damage and even upset your health. Because these effects frequently go unseen in the wall cavities, attics and crawl spaces, the visible sign of condensation on glass is a good clue that humidity levels are too high. And while window condensation and musty odors might be seen as annoyances, they can grow into more serious concerns such as water stains on walls and ceilings if left alone.

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 comfy 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 St. Paul a call or stop by the showroom.

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