Remtech Environmental > Resource Library > Environmental Services Blog > Can Window Condensation Lead to Mold?

Issues related to indoor humidity and excess moisture are not limited to the summer months. Whether the weather is cold or warm, moisture in your home can lead to the development of mold. One place you might not expect mold to develop is around your windows and on your window sills. Window moisture and condensation is one of the most common contributors to mold development.

What Causes Window Moisture And Condensation?

Window condensation will often manifest during cold and/or foggy evenings or mornings. There are several common causes of window condensation:

  1. High Indoor Humidity: Ideal indoor relative humidity is around 40%. Higher humidity can lead to window moisture and condensation.
  2. Malfunctioning HVAC System: Your HVAC system regulates humidity as well as temperature. A failing heating and air conditioning system will contribute to excess moisture inside your home.
  3. Drafty or Failing Windows: Besides releasing as much as 25% of your home’s heating and air conditioning energy, drafty windows can allow moisture to invade your home. Signs your windows require repair or replacement:  Difficulty regulating indoor temperature, cracked or damaged window panes, worn out weather seals and glazing, peeling caulking around windows, or moisture inside windows.
  4. Humidifiers: If you notice condensation collecting around windows and window sills where humidifiers are in use, it is important to dry excess moisture and occasionally turn off the humidifier itself.

What Results From Window Condensation?

Moisture and condensation may not seem like an immediate threat to your home’s integrity; however, it can lead to peeling paint and plaster, wood rot and water damage, and the development of harmful mold.

If the condensation is the result of failing windows, it could result in other issues including:

  • Poor energy efficiency and higher energy bills
  • Repair or replacement of your HVAC system
  • Excess dust and dander in your home
  • Allergies and poor health for your family

What Should Homeowners Do About Window Moisture And Mold?

If moisture is collecting on window sills, make sure you dry it thoroughly as soon as it develops. Once mold develops on your window sill, it can be difficult to remove. If you do see mold development, follow these steps:

Step 1: Assess the extent of the situation. If the mold is less than one square yard, you may be able to remove it yourself. For more about mold removal, read this (note: it is always best to call a professional to remove mold, as it can hide in places the untrained eye cannot see.)

Step 2: If it is possible, remove mold according to the steps laid out in the link above.

Step 3: If there is too much mold to remove yourself, contact a professional mold remediation company.

Step 4: Correct the source of the issue by repairing or replacing windows, HVAC system, or whatever is causing the excess moisture and condensation.

Step 5: Consider installing a whole-house dehumidification system to help further control humidity and moisture in your home.

Whenever moisture and mold develop in your home, we are here to help. For more information about mold remediation and removal, contact us.