Question:

Our house is 6 years old. We live in Lawson, Mo. Our inside temperature is 70, 71 degrees, day and night. Usually when the temperature outside is in the low 20s or teens, we have a lot of condensation on the inside of our Weather Shield windows. Our humidity inside is 36 to 40 percent. It seems to us the only thing that could be wrong is the windows are leaking air. Our windows were very expensive. We also added storm windows on the north side, and that did not help. We are out of options. Would you please help? Our windows are triple pane, with argon gas.

Answer:

When you see condensation forming on the inside of your windows, it is an indication that there is too much water vapor in the air of your home (measured in relative humidity) or that there is insufficient air circulation next to the windows on which the condensation is occurring.  The good news is that there may be nothing wrong with your windows.   I do have a couple of suggestions for your situation.

 

One idea would be to reduce indoor relative humidity by running your kitchen or bath exhaust fans until the condensation disappears.  The fans will be more effective if you open a window somewhere else in the house to provide the replacement air, while running the fans.  Make sure that the fans you use do exhaust to the outside (not just to the attic or recirculate within the house).  Also, make sure blinds or draperies are open and not trapping moisture between the window treatment and the window.

 

Another thought is that you are experiencing “seal failure” with your windows.  In this situation, the condensation would typically be in-between the panes of glass.  An insulated glass window unit has 2 or move sheets of glass separated by a spacer and sealant system creating a “sealed” air space.  If the seal is broken anywhere along the edge, moisture may appear.  The actual point of “failure” is usually not visible because the seal is hidden inside the sash or frame.  If you think you have seal failure, I would recommend that you contact your builder or window representative to verify that your windows are failing and would be covered under a warranty.

 

Good Luck.