Moisture is any building pro’s nightmare, so getting a call from a homebuyer that they have moisture on their windows might be concerning. But depending on the windows, there’s likely an explanation that should ease concerns—window condensation, not leakage. More importantly, it’s something you can help them avoid altogether.

Condensation is common on aluminum windows simply due to the physics of hot-cold transfer. In the winter, when warm, moisture-laden interior air comes in contact with the cooler surface of an aluminum window frame, the air will drop its moisture onto the cooler surface as it loses heat, creating condensation on the frame and glass.

How Can You Avoid Window Condensation?

To reduce the opportunity for window condensation, your homeowners can consider these options:

  1. Control the humidity level in the home: Educate your homeowners about regulating the humidity levels inside the home during the winter. When it’s freezing outside, the interior humidity level should not be higher than 40%. Using mechanical ventilation systems, along with proper use of cooking vents and bathroom fans, can help with this. If necessary, install a dehumidifier.
  2. Increase circulation: Along with mechanical ventilation, running ceiling fans can help circulate the air and prevent moisture-laden air from settling on windows. Ventilation and circulation are particularly important when having a party, as more people equals more moisture.
  3. Use smart thermostats: Some smart thermostats can automate ventilation based on moisture levels in the home.
  4. Use drapes wisely: Heavy, thick drapes may help seal heat in, but they also need to allow ventilation occasionally.
  5. Wait a year: Keep in mind that the materials used to build the home, such as the drywall, paint, and slab, will release moisture, so condensation may be greater in the first year or so.

In addition, consider the windows themselves before purchase. Though any window can have condensation if the conditions are right, it’s most common with aluminum windows. If aluminum windows are desired, opt for dual-pane, insulated glass; a single-glazed window is more prone to sweating.

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