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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 improve your heating costs by holding more temperate air in your house while resisting 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. 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. Instead, it means your windows are being efficient.

So, what is causing the condensation on your windows? And, more importantly, what types of condensation should make you concerned about your window’s health? 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 possible problems during the installation process. Condensation on windows and doors is not produced by the window or door product. Instead, it comes because of high humidity levels in your house.

As it turns out, the signs of condensation more often than not is a result of the increased energy efficiency of your new windows. Air with more humidity keeps water vapor until it connects 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 usually the coldest part of the home, condensation shows up on windows initially, in the form of water droplets or frost on the roomside of the house’s window. As the air inside gets drier, or as the glass surface becomes warmer, condensation begins to disappear.

Many 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, 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 appear 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 include the advanced, energy efficient technology of present-day windows. Additionally, other home repairs, such as adding a new roof or siding, might also build a tighter seal against air infiltration in your room. Because of that, your home may retain 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 appear due to high outdoor humidity, little or no wind, and a clear night sky. It forms 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 room isn’t leaving due to increased energy efficiency, there’s a higher possibility to see external condensation in these situations.

You can address exterior condensation by opening curtains at night to warm up exterior glass and promote air circulation by cutting back any shrubbery that might be interfering with windows. Adjusting the air conditioner a few degrees warmer can also improve the situation.

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

Sources of humidity in your home 

The most frequent way roomside humidity increases is through everyday activity. 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. Add today’s energy efficient, well-insulated homes and you can start to understand why that humidity can often find no means of escape.

As a result of this better insulation, some windows can have a strip of condensation that forms all the way around the roomside of the window. Normally, this occurs 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 Damage My Windows?
One area where condensation on windows should become an immediate issue, however, is if condensation is noticed between the two sealed panes of insulating glass in multi-pane windows. In this situation, condensation is a result 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 problem with your windows. It serves as a sign to the possibility of other hidden, potentially costly problems elsewhere in your house.

igh indoor humidity can eventually cause 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 sign that humidity levels are too high. And while window condensation and musty odors might be seen as nuisances, they can evolve into more severe 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 alert to high humidity in your house, one that can easily be resolved 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 doing their jobs properly, give Pella Windows and Doors in Norwalk a call or stop by the showroom.

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