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

If you find condensation on your window, don’t stress! It isn’t time to start diagnosing 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. Rather, it means your windows are working well.

So, what is leading to the condensation on your windows? And, more importantly, what signs of condensation should raise alarms about your window’s strength? Here are the facts about window condensation:

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

In reality, the sight of condensation more often than not is an outcome 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. Since glass surfaces are often the coldest part of the house, condensation can be seen on windows initially, 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 becomes warmer, condensation begins to lessen.

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, changing room temperatures, air register location, and the type and size of the window can all increase the chances of roomside condensation. Other influnences such as 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 occasionally see condensation on opposite sides of the window?
Your previous windows could have been drafty or didn’t feature the advanced, energy efficient components 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. As a result, your home may keep more humidity making condensation more likely to be seen than before.

In the heat, this same phenomenon can be noticed on the outside of your windows. Exterior condensation can form due to high outdoor humidity, little or no wind, and a clear night sky. It establishes itself 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 escaping due to increased energy efficiency, it’s more likely to see external condensation in these situations.

You can address exterior condensation by opening shades at night to warm up exterior glass and promote air circulation by cutting back any bushes that might be interfering with windows. Setting the air conditioner a few degrees warmer can also help.

For roomside condensation, there are a few factors that can determine the humidity in your house. Here are some common culprits that can lead to 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 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 appears all the way around the roomside of the window. Normally, this happens when the center of the glass stays warmer than the glass closest to the edge. It isn’t an indication 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 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 sign 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 concern with your windows. It serves as an indicator to the possibility of other hidden, potentially costly problems elsewhere in your home.

High indoor humidity can lead to structural damage and even affect your health. Because these effects frequently go without notice 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 develop into more serious concerns such as water stains on walls and ceilings if left unchecked.

In the same way, left unaddressed, condensation issues can mean 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 worse. 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 as they should, give Pella Windows and Doors in Northern Virginia a call or stop by the showroom.

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