Is your glass “sweating”, is ice forming on the inside surface of your windows or doors? The problem is not your new windows, the problem more than likely is excess humidity in your home.

Humidity, which consists of warm air borne water vapor, is drawn towards cooler surfaces, such as your windows and doors. Surfaces that are below room temperature are more likely to show condensation.

What causes condensation?

When certain conditions exist, condensation can occur both inside and outside your home. The source of condensation is humidity, or air borne water vapor, which is present in all air. When this water vapor comes in contact with a cooler surface it will condense, similar to your bathroom mirror after you take a hot shower. Condensation can occur on windows and doors during the winter if the humidity level is high enough.

Do windows cause condensation?

No. Windows do not cause condensation; they simply are doing what they are designed to do. By keeping the warm air in your home the windows also stop the humidity from escaping and that humidity becomes visible on the glass.

What is temporary condensation?

Temporary condensation will not last long and will eventually disappear.
Temporary condensation can occur:

After baths and showers, laundry, cooking or dishwashing.
At the start of the heating season. Your home can retain moisture from the humid summer months.
When the outside temperature experiences drastic changes. A sharp drop in temperature, especially during the heating season can cause temporary condensation.

During construction or renovation of your home. Most building materials retain moisture during shipping or storage; this moisture can be released into the home but will eventually dry out.

What problems are associated with condensation?

Excess moisture in your home can cause not only structural problems but it also presents a health risk as well.
Problem condensation will show itself when:

The condensation remains on the windows throughout the day.
You can see condensation on the walls.
If you notice a musty smell in your home.
You notice mold or mildew on various surfaces throughout the home.

What steps can I take to reduce humidity in my home?

The two main things you can do are to control sources of moisture and increase ventilation. To decrease or control excess humidity and condensation:

• Closely monitor the furnace humidifier and any other humidifying devices.
• Be sure louvers and vents for the attic, basement and/or crawl space are open, adequately sized and cross-ventilated.
• Run exhaust fans for kitchen, bathroom and laundry rooms for longer periods.
• Make sure exhaust fans vent directly outside, not into attics or crawl spaces.
• Be sure chimneys are free and clear so moisture in combustion gases can escape.
• Follow the manufacturer’s instructions for venting gas appliances. In most cases, that will mean directing vents to the outside of the home.
• Make sure your furnace is in proper working order and is serviced regularly.
• Store firewood outside or in the garage – as wood dries, it gives off moisture.
• Open a door or window for several minutes each day to refresh the inside air.
• Open window coverings – such as blinds, shades, drapes and curtains – during daylight hours to increase airflow over the glass. Air out your house a few minutes each day.