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Why is There Condensation on the Inside of My Windows?

February 15, 2018

Do you notice condensation on the inside of your window during the winter? If so, it’s not an uncommon occurrence. Window condensation in winter is triggered by a number of dynamics. To begin with, homes are quite “sealed” today and outside ventilation is usually lacking. As a result, indoor air tends to hold high (and often damaging) levels of moisture levels in winter.

If you’re concerned about the amount of condensation on the inside of your window, there are remedies available. The aim is to remedy the situation before there’s any damage – like ruined window frames, or worse still, mold growth around the sills. Indeed, window condensation may also point to poor indoor air quality – again related to the lack of proper ventilation throughout.

How to fix condensation on the inside of your window?

When there’s too much condensation on the inside of your window, it’s because warm air inside the house is condensing on a cold window. In some situations, condensation can form in between the windowpanes. Here, the potential for damage is greater, and a proper fix even more urgent.

Turning down the humidifier

When you notice condensation on the inside of your window (or in the bathroom), one of the most basic solutions is to lower the humidity setting on the humidifier attached to the furnace.

The humidifier unit will then release less moisture and window condensation will be reduced.

Better indoor air circulation

Improving the air circulation inside the home will also reduce high levels of condensation. With the furnace, its possible to have the fan running consistently, thus creating air circulation. For some, operating a ceiling fan in the winter can also be helpful (fans should rotate clockwise).

Improved weather-stripping

By improving the weather-stripping around windows, warm indoor air is blocked from escaping in the winter. This happens to be one of the easiest and most effective remedies for reducing window condensation. Weather-stripping will also make your home far more energy efficient.

Retrofit the storm windows

Short of replacing windows, there’s an innovative retrofit now available from MAGNETITE. The patented frame assembly is retrofitted into an existing window, thus providing a snug fit that locks into place. The retrofitted window becomes fully airtight and insulated at the same time.

Checking for humidity issues

In winter, humidity levels should be around 30% in order to prevent window condensation. If an exterior window shows unusually high condensation, it’s a sure sign that indoor humidity levels are too high, relative to the indoor temperature. Very high levels can be professionally measured.

Bathroom and kitchen fans

Proper use of bathroom and kitchen fans is essential in controlling indoor humidity. Showers and cooking actually releases a lot of air moisture, and a proper fan system will allow that moisture to escape. Exhaust fans, properly vented to the outside, are critical in reducing indoor air moisture.

Fixing the vapour barrier

When indoor condensation is a result of mechanical issues like air leakage or poor insulation, a retrofitted vapour barrier may be the answer. Vapour barriers are specifically designed to stop air moisture from collecting. Here, professional advice and installation is highly recommended.

When condensation on the inside of your window becomes untenable, there are a host of possible remedies. Some are “low-tech” and personally manageable, while others require the expertise of a professional. Whatever the case, it’s worth doing right the first time around. 

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