Window Condensation Facts and Tips

window condensation


Here is a brief explanation of why window condensation occurs and some thing’s you can do to help reduce or eliminate window condensation altogether.

Due to building sciences improving, new homes built today are much more airtight and energy efficient than they have ever been in our home building history which has caused the indoor relative humidity (moisture) levels to rise. When the outside air temperature and/or humidity is significantly different than the indoor air temperature and/or humidity you may start to experience condensation form at the leading edge of window glass and near window and door edges where they open. This naturally occurs in our extreme climate here in Minnesota and is not due to a failure in your window or door. Window condensation left uncontrolled may lead to damage to the window, door, window treatment, finish and/or wall cavity.

Here are a few tips that will help reduce the humidity level inside your home;

  1. Increase ventilation by adjusting your air exchanger fan (if equipped)
  2. Turn on bathroom exhaust fans
  3. Turn on ceiling of free standing circulating fans
  4. Crack open doors or windows
  5. Inspect dryer venting making sure it is properly vented to the exterior
  6. Reduce the amount of clothes and dishwashing
  7. Reduce the number of baths/showers taken
  8. Reduce the amount of baking/cooking
  9. Make sure the combustion air intake located in your mechanical room is unobstructed
  10. Make sure all floor heat registers are open and heat runs coming from furnace are open
  11. Keep window treatments/blinds open so air can circulate around the glass of the window
  12. Reduce the number of plants, animals and people located in your home


Semler Homes provides its customers with a humidistat at closing which allows you to know exactly what your indoor relative humidity is which will allow you to gauge how effective your moisture reducing practices are. If you do not have one of these gauges you will find them to be inexpensive at your local hardware store.