Clera Windows + Doors Blog

Is Window Condensation a Bad Thing?

It is that time of year again where most of us will be making the switch from air conditioning to heat. There is nothing better than coming in from the cold to a toasty home, unless of course your home is expelling all the heat you are pumping in to it. If you notice your furnace is working a bit harder than it should be, or if there are cool zones throughout your home, then there is most likely a leak present. If you happen to see condensation on your windows, then the problem has been resolved. When cold air leaks in to a warm house, the result is moisture buildup around your windows. This is due to the temperature variance, and is a bad sign. Condensation can also occur in the spring and summer months, due to cooler nights. Basically, when the dew point in the air comes into contact with a surface with a lower dew point (i.e. your windows), moisture buildup occurs. While some condensation is not necessarily a bad thing, an excess amount is something that should be addressed.

How to fix window condensation issues

It might come as a surprise that condensation is not due in part to a faulty window. Many homeowners believe that caulking their windows are replacing them with newer ones will automatically fix the problem. In fact, doing so can actually lead to greater condensation. The process is actually quite simple to understand. A home that is sealed up better will retain more humidity and moisture then one that is not. While this not a bad thing in itself, it can lead to increased condensation at the base of a window due to the large variance between the dew point temperatures.

Fixing condensation requires monitoring the humidity levels within the home in relation to the temperature outside. This is especially true for homeowners that live in colder climates. Fortunately, reducing the humidity in a home does not require a lot of work. Buying a dehumidifier is a great way to keep moisture levels where they need to be. These devices are best placed in damp zones such as basements, because they will also prevent mold from growing. Having proper ventilation in your home for devices that put off heat (dryers, ovens, etc.) will also greatly reduce the amount of moisture present. Lastly, one can open the windows for a minute or two to air out the house. The best time to do this is when the external temperature is closest to the internal, so as to minimize heat or air loss.

Controlling Condensation

By following these tips, one can significantly reduce the amount of condensation present on windows. Excess moisture buildup can do damage to window frames and walls, so ensuring proper humidity levels is very important. The condition and number of windows in a home will determine the steps that need to be taken to control the internal environment. Newer windows will help reduce any leaking air into the home, which can further increase condensation buildup. It is important to remember that all windows are rated for their ability to withstand condensation based on a temperature factor (TF) scale. Choosing a higher rated window will ensure the maximum possible protection against moisture buildup.



  • Avatar for Jacob L. - Oakville Jacob L. - Oakville says:

    This is really helpful. I was not even aware of the rating system. This makes sense though. At least I know now to get a higher temperature window. My house is sealed up pretty well, and I could not figure out why there was so much condensation around the bases. I’ll probably be investing in a dehumidifier, and I may need to replace some windows in the near future.

  • Avatar for Michael Lan Michael Lan says:

    Great post. Yes, its definitely about turning on the heater and keeping that heat inside the house. My new replacement windows in my Toronto home has energy saving benefits, but it’s also made the house quiet too!

  • Avatar for Greg Greg says:

    Great stuff! I hadn’t stopped to think about it before, but just because my house is insulated well does not mean I am not going to have moisture buildup. I think the last tip is a great one. Opening up the doors and windows for a bit does wonders at keeping the air dry.

Leave a Reply

Your email address will not be published. Required fields are marked *