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Throughout the year, window condensation – or window sweating – is a natural occurrence around the windows of your home or office, and it happens most frequently on new windows. That’s right. Condensation is not a sign of a faulty window. Actually, it’s a sign of an energy efficient installation. New windows are more likely to collect a small amount of water because they conserve energy more efficiently.

Here’s why: condensation is formed when warm air comes in contact with cooler air. Thus, during winter months, the warm interior air at the window reacts with the cold winter air outside, and condensation forms. In the summer, the opposite happens. The cold interior air meets the warm exterior air at the window, and condensation may form on the exterior of the window.

New windows conserve warm and cool air inside more effectively; therefore, water is more likely to condensate. That’s why window condensation is very common in the Northeast and climates throughout the U.S. where interior and exterior temperature differences reach extremes.

This year, 2015, we’ve had a pretty significant winter across the East Coast, meaning anyone who has installed new windows has likely experienced a higher-than-usual amount of condensation.

Is Condensation Caused by the Window?

No, not in the way you may be thinking. Condensation shouldn’t alarm you; your windows are not faulty. In fact, a small amount of condensation during the coldest and hottest months may actually be a good sign. It means that your windows are effectively holding warm or cool air inside.

Today’s windows are extremely energy efficient. They’re designed to conserve the energy inside your property, and thus, the temperature difference from outside to inside is greater. That’s why if you’ve recently replaced your windows, you might notice some condensation. Your old windows weren’t properly conserving the warm air inside. They were drafty, and the warm, moist interior air was escaping out the window, causing the air around the window to be a consistent temperature.

When Does Condensation Most Often Occur?

Condensation commonly occurs in northern U.S. climates, in the Mid-West and further south during cold snaps and heat waves. It is most likely to form when the difference between interior and exterior temperatures is extreme, i.e. during a Polar Vortex or during the hottest, most humid summer months.

In the winter, condensation usually forms on the interior of the window pane. And during summer months, it forms on the exterior of the window, similar to morning dew. Although in summer, condensation often burns off as the day progresses.

Additionally, when the humidity inside your property is high, there is more moisture in the air, and condensation occurs more frequently. In homes, for instance, condensation commonly collects on windows after a shower, when doing the dishes, or when running a humidifier. This happens because the warm, moist air isn’t able to escape at the window and condensation forms. At the beginning of the heating season, condensation is very common, because the heating system brings more moisture into the air. As the season progresses, this moisture is absorbed by the building, reducing the occurrence of condensation.

When Is Condensation a Sign of Something More Serious?

Excessive condensation can be annoying and, in some cases, a sign of something more serious. First, it may be an indication that there is excessive, “problem” moisture in the air. If you notice water spots on the ceiling or walls, your heating or cooling system may be putting too much moisture in the air or you may have leaks on your property. The result is a higher humidity level, which causes condensation to form more abundantly. To remedy this you need to find the cause of the humidity at the source.

Very rarely is condensation a sign of a faulty window, but if water is collecting between two panes of glass, the seal may be faulty. In these cases, the window may need to be replaced or the seal refitted.

Preventing Window Condensation

So what can you do? There are a few quick fixes for window condensation, including:

  • Controlling Interior Humidity: If there is too much moisture in the air, the result can be excessive condensation. The remedy may be something as simple as moving plants and fish tanks away from windows. But the source of humidity may be something more serious, like a faulty cooling system. We recommend either identifying the source, installing a newer HVAC system, or buying a dehumidifier, preferably for your ventilation system.
  • Increasing Ventilation: Better air circulation improves the airflow along the window, which may help reduce the occurrence of condensation. For instance, in the home, running an exhaust fan when using the shower is a common method for circulating warm, wet air. Additionally, ceiling fans, cracking a window, and ventilation systems can also increase airflow and reduce condensation. Sometimes, all you need is just a bit more air movement to keep the temperatures constant.
  • Opening Drapes/Blinds: Heavy drapes reduce the flow of air at the window, which can contribute to condensation. By opening drapes and window treatments, the air moves more freely along the window, effectively reducing condensation.

Window condensation or sweating shouldn’t be a cause for alarm. Today’s windows and building materials are designed to create a stronger interior seal. This is a good thing and it helps to reduce the cost of heating and cooling.

Your building will adapt and the condensation will likely remedy itself. If it does not, try one of the above methods. When all else fails, cracking a window or buying a dehumidifier and placing it in the room should do the trick.

If you have any concerns about your window or suspect they may be faulty, be sure to give us a call at 1-888-380-2376.