Winter Window Moisture


You’re freezing in the minus teens, but your windows are perspiring. Some window moisture is to be expected, but when it starts to drip off the window pane and pool in the sill, you could end up with water damage and mold build-up around and below your windows.


The Culprit: Water Vapour

So how to do you prevent moisture on windows? Many people immediately jump to the conclusion that they need new windows. While you may indeed do well to update your windows with good storm windows, the windows themselves are probably not the problem. Rather, they reveal the symptoms of the real problem – trapped vapour within your home. When vapour in your home hits the cold window glass, it condenses and creates a wet, drippy mess.

And a wet, drippy mess can become a dangerous mold problem.


The Downside of Energy-Efficiency

Modern homes are designed to be airtight and are essentially wrapped in a vapour barrier to prevent interior moisture from escaping through the walls and soaking into your home’s insulation. While this allows you to heat your home efficiently and greatly reduce your heating costs, it leaves nowhere for the moisture in your home to escape.

Moisture originates from such activities as cooking, cleaning, showering, washing and drying clothes, etc. Excessive moisture can create a high humidity level that can encourage mold growth which, in turn, leads to poor indoor air quality and potential respiratory problems.

In other words, modern homes and modern lifestyles inevitably produce a moisture problem.


What is a Safe Humidity Level?

Generally speaking, a safe humidity range is between 30 and 50 percent. While high humidity levels can bring about the problems outlined above, low humidity levels can be problematic as well. If the humidity level in your home is too low, you may suffer from nose bleeds, dry eyes, skin and throat. Dry air can also damage wood furniture.

You can measure the humidity in your home easily with an inexpensive humidity reader from your local hardware store.


Things You Can Do to Reduce Moisture in Your Home

You could move into a big, drafty home and resolve to cook, shower and wash your clothes less often. Or you can try the following tips for reducing moisture and window ‘sweating’.


1.       Wait a While

During the summer, your home absorbs moisture. Once the drier winter months set in, your home will dry out a bit and your condensation problem may clear up on its own.


2.       Turn Down any Humidifying Sources in Your Home

Although you may not operate a humidifier in your home, your furnace may operate a humidifier whenever it is running. If you are able to turn it down, it may help to eliminate moisture from the air.


3.       Use Kitchen and Bathroom Fans More Often

Don’t just turn off the bathroom or kitchen fan once you’re done showering or cooking. Let it run for a while longer to help ventilate some of the moist air produced by these activities.


4.       Install Storm Windows

Storm windows are insulated windows you put up in the winter. The space between the two windows allows your regular (interior) window to stay warmer, which helps reduce condensation on your windows. While storm windows themselves may produce condensation, reduced condensation on your interior windows will help prevent water damage within your home. Excessive condensation on storm windows could indicate a leak around your regular window.


5.       Make Sure Your “Moisture Exits” are Open

This includes your attic louver and fireplace damper. Make sure they’re not blocking the escape of moisture-laden air into the great outdoors.


6.       Dehumidify!

Keep your dehumidifier plugged in all the time so that it will turn on whenever the moisture in your home rises above the optimum level.


7.       Exchange Your Air (Without Losing Your Heat)

Although typically more expensive than a dehumidifier, installing an air exchange or air-to-air heat exchange system is one of the best ways to bring in fresh, dry air, thereby reducing the moisture level and improving the air quality within your home.