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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 bill by retaining more temperate air in your room while resisting the elements outside. However, you may start to notice condensation settling on your windows and doors during colder months.

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

So, what is causing the condensation on your windows? And, more importantly, what types 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 associate the signs of condensation in the months after installing new windows with potential 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 room.

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 more humidity holds 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 most likely the coldest part of the room, condensation shows up on windows more frequently, in the presence 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 dissipate.

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 another in the same room doesn’t. Air circulation, changes in room temperatures, air register location, and the type and size of the window can all impact the likelihood 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 can be noticed around a window.

Why do I occasionally see condensation on opposite sides of the window?
Your previous windows might have been drafty or didn’t include the advanced, energy efficient components of present-day windows. However, other home repairs, such as installing a new roof or siding, might also create a tighter seal against air infiltration in your house. Due to that, your home may retain more humidity making condensation more likely to be seen than before.

In the heat, this same phenomenon can be observed 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 house isn’t leaking due to increased energy efficiency, there’s a greater chance to see external condensation at times like these.

You can deal with exterior condensation by opening curtains at night to warm up exterior glass and promote air circulation by removing any bushes that might be blocking windows. Programming the air conditioner a few degrees warmer can also make a difference.

For roomside condensation, there are a group of factors that can influence the humidity in your house. Here are a few common culprits that can cause 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 bring moisture to the air in your home–topping out at four gallons or more per day in some homes. Include 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 shows up all the way around the roomside of the window. Normally, this is created 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 Hurt My Windows?
One place where condensation on windows should become an immediate issue, however, is if condensation is appearing between the two sealed panes of insulating glass in multi-pane windows. In this instance, condensation is a sign of seal failure and the insulating glass must be replaced.

More likely though, condensation on your windows doesn’t mean there is a problem with your windows. It serves as an indicator to the possibility of other hidden, potentially pricey problems in other areas in your house.

High indoor humidity can lead to 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 signal that humidity levels are too high. And while window condensation and musty odors might be seen as bothersome, they can grow into more serious concerns such as water stains on walls and ceilings if left unresolved.

In the same way, left unaddressed, condensation issues can cause window problems over time. Make sure to take continual roomside condensation seriously. Think of it as an early warning to high humidity in your home, one that can easily be solved before it gets serious. Understanding condensation is just the beginning to keeping your home cozy 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 Woburn a call or come into the showroom.

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