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Window Condensation: Understanding What It Means

Window Condensation: Understanding What It Means

It’s almost that weather where energy efficient windows can impact your heating bill by holding more temperate air in your house 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 stress! It isn’t time to start looking for something wrong with 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 working well.

So, what is causing the condensation on your windows? And, more importantly, what kind of condensation should cause concern about your window’s health? Here are the facts about window condensation:

Do my new windows or doors cause condensation?
Some homeowners pair the presence 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 because of high humidity levels in your home.

As it turns out, the signs of condensation more often than not is a result of the improved 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 usually the coldest part of the house, condensation can be seen on windows first, in the indication of water droplets or frost on the roomside of your window. As the air inside grows drier, or as the glass surface heats up, condensation begins to dissipate.

More than a few factors go into whether you might find condensation on your windows. You might even find 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 influence the chances of roomside condensation. Even the glass type, window coverings and screens and proximity to a water source can all have an impact on what levels of humidity can be noticed around a window.

Why do I occasionally see condensation on opposite sides of the window?
Your previous windows may have been drafty or didn’t have 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 house. As a result, your home may retain 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 form 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 home isn’t leaving due to increased energy efficiency, there’s a higher possibility to see external condensation at times like these.

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

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

Sources of humidity in your home 

The most common 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 add 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.

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. 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 Hurt 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 result of seal failure and the insulating glass will need to be replaced.

Most often though, condensation on your windows doesn’t mean there is a problem with your windows. It serves as an alert to the possibility of other unseen, potentially pricey problems elsewhere in your home.

High indoor humidity can result in structural damage and even affect 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 nuisances, they can grow into more immediate concerns such as water stains on walls and ceilings if left alone.

In the same way, left unaddressed, condensation issues can cause window problems over time. Make sure to take reoccurring roomside condensation seriously. Think of it as an early alarm to high humidity in your house, one that can easily be resolved 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 Boston a call or visit the showroom.

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