Prevent Window Condensation - Where's That Water Coming From?

One of the things many homeowners hope that replacement windows can help with is to prevent window condensation concerns. At the least condensation can stop us from seeing out of our windows properly. But it can do much more than that; condensation can damage and even ruin paintwork and plaster too.

How to prevent condensation on windows is not only a matter of new windows alone, although double or triple paned designs should certainly help to put a stop to the problem.

One of the gases in the air is water vapor. Condensation is water vapor that `condenses' or becomes concentrated and returns to liquid form when moisture laden air comes into contact with a surface colder than the air temperature. It's really the opposite of steam, which is produced when liquid water is heated.

That's why you don't get condensation on the outside of windows. It can only form on the inside where the warmer room air meets glass cooled by the outdoors climate.

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Because dual or triple paned glass has a layer of air (or other gas) between the panes (should be not less than �-inch). Condensation is reduced or stopped because the inner glass and frame does not lose so much heat to the outside. So therefore the water vapor inside does not get a colder surface to condense onto.

This problem can still occur though within the window if the seals are less than perfect. Substances called desiccants inside the spacer help to dry up any moisture that may appear initially after installation. But if this fogging continues unabated, then the window seals are faulty.

Wood windows resist and prevent condensation better than aluminum. And better ventilation can help to prevent the windowpane from misting up too. But stopping really bad condensation sometimes means your home needs a device called a de-humidifier.

New windows can certainly help though, especially with low-e glass. And one of the ratings on NFRC window labels is the Condensation Resistance (CR) rating. This will help you to judge how good a window is at preventing condensation. But this rating is voluntary and unfortunately some manufacturers do not volunteer the information - no prizes for guessing why that is.

Author Notes:

Anthony Lee contributes and publishes news editorial to http://www.replacement-windows-n-shutters.com.  Find everything you need to know about replacement windows, shutters, tinting, basement, fiberglass windows and more.