Preventing Condensation on Windows

Condensation on a windowOne of the more annoying problems homeowners sometimes face is a buildup of condensation or “sweat” on windows.  Condensation is water vapor that can accumulate either on the inside or the outside of your windows or between the window panes.

Can window condensation damage my windows?

Windows are designed to handle moisture on the exterior. However when condensation occurs inside or between panes, it can potentially damage window frames and rot wood molding around your window.

Exterior condensation

When it occurs on the outside of your windows, condensation is just dew which forms when the temperature outside is below the “dew point.” There’s not much to be done about it, but if it really bothers you, try one of the windshield treatments like “Rain-x.” These make the water slide off the window.

Getting rid of condensation on interior windows

Condensation on the inside tends to occur in cold weather and is caused by a combination of excessive moisture in the air and warm air from the house meeting the cold glass of the window. Bathrooms, laundry rooms and kitchens are prime locations in most homes.   Some tips for preventing it:

  • Open your windows (probably not something you want to do in the middle of winter!)
  • Install a bathroom or kitchen fan – circulating air helps prevent moisture buildup.
  • Install storm windows – Air in the space between the interior window and the storm window keeps the inside window from getting as cold as it would otherwise.
  • Can’t use storm windows or want something more budget-friendly? Try a window insulation kit. These kits have clear plastic film which attaches to the frame with double sided tape and shrinks to fit when warmed with a hair dryer. Putting this film on the inside of your windows will do a good job of preventing condensation.
  • Get a dehumidifier to reduce humidity in the indoor air.

Condensation between panes of a window

Condensation between the glass panes can be a sign of a more serious issue with your window itself.  It may mean the seal in between the panes has been broken, or the desiccant (material intended to keep windows dry) has become saturated with water.   Depending on the type of window you have, you may be able to replace the pane causing the problem, but it’s more likely that the only solution will be to replace the window.  


  If you’re in or near Edmonton, contact Reflect Window and Door for help and advice. Reflect has been serving the greater Edmonton area since 1985 – offering expert window and door installation and repair, and carrying a wide assortment of door and window hardware and accessories. We’d be happy to give you a free estimate on replacement windows at your convenience.