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

If you see condensation on your window, don’t panic! It isn’t time to start investigating 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. Just the opposite, it means your windows are doing their job.

So, what is leading to the condensation on your windows? And, more importantly, what signs of condensation should raise alarms 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 presence 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. Rather, it comes due to high humidity levels in your home.

In reality, the sight of condensation more often than not is an indication of the increased energy efficiency of your new windows. Air with more 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. Since glass surfaces are most likely the coldest part of the home, condensation shows up on windows first, in the presence of water droplets or frost on the roomside of your window. As the air inside gets drier, or as the glass surface heats up, condensation begins to dissipate.

Numerous 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 one on the other side 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 appear around a window.

Why do I at times see condensation on opposite sides of the window?
Your previous windows might have been drafty or didn’t feature the advanced, energy efficient technology of today’s windows. But, other home repairs, such as adding a new roof or siding, might also establish 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 noticed 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 establishes itself in the same way as roomside condensation, when the temperature of the glass is cooled 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 at times like these.

You can manage exterior condensation by opening window coverings at night to warm up exterior glass and improve air circulation by trimming any bushes that might be blocking windows. Adjusting 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 home. 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 bring 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 get an idea why that humidity can often find no way to escape.

As a result of this better insulation, some windows can build a strip of condensation that shows up all the way around the roomside of the window. Most often, this occurs 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 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 mark of seal failure and the insulating glass should 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 hidden, potentially pricey problems to be found in your room.

igh indoor humidity can result in structural damage and even impact your health. Because these effects frequently go unseen in the wall cavities, attics and crawl spaces, the visible presence 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 develop 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 reoccurring roomside condensation seriously. Think of it as an early alarm to high humidity in your room, one that can easily be dealt with before it gets worse. 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 as they should, give Pella Windows and Doors in Hunt Valley a call or come into the showroom.

Back to Blog