Windows Direct
About Us products gallery Guide Contact
Main Image
 
 

About Us

What is condensation?

Moisture on the windows is a form of condensation. So is the water that forms on the outside of a glass of iced tea in the summer. It comes from water vapor in the air. It can appear on the interior or exterior of the window glass.

What causes condensation?

When warm, moist air comes into contact with cooler surfaces, the excess moisture in the air condenses. That’s because the cooled air next to the cool surface can’t hold as much moisture as the warmer surrounding air.

What does the condensation on windows mean?

While it may seem natural to blame the windows or doors, interior condensation is really an indication of excess humidity in the home.

What is humidity?

Humidity is water vapor, or moisture, in the air. Usually it’s invisible. In the form of steam or ground fog, enough has condensed to be seen. All air contains a certain amount of moisture, visible or not.

Where does indoor moisture come from?

There are many things that generate indoor moisture. The normal perspiration and breathing of a family of four adds about half a pint of water to the air every hour. Cooking three meals a day adds four or five pints of water to the air. Each shower contributes another half-pint. In fact, every activity that uses water (like dishwashing, mopping floors, doing laundry) adds moisture to the air. Daily living activities of a family of four can add more than 18 gallons of water a week to the air in their home. And the more water vapor in the air, the higher the relative indoor humidity. Other contributors include house plants and the burning of fossil fuels (especially kerosene, natural gas, and oil).

What does excess humidity do to my home?

Excess humidity contributes to the deterioration of any home. It can pass through walls and freeze in the insulation. In spring it melts, damaging your ceiling and walls. Or, excess humidity can force its way out through siding to form blisters under exterior surfaces. Excessive relative humidity levels may also lead to higher levels of unwanted mold and mildew growth in homes.

Does condensation occur only in winter?

Condensation is most common in winter, but it can occur whenever water vapor in the air comes in contact with a surface temperature lower than the dew point (the temperature at which air becomes saturated and produces dew). For example, on cold winter days the moisture in the warm, interior air can condense on the typically colder glass surfaces. In rare instances, during the spring and fall (and occasionally, during hot, humid summer days), exterior condensation can also form on windows. This is usually a good indicator of the presence of energy efficient windows.

Does the severity of the condensation depend on the age of the house?

Generally, yes. Years ago, before energy efficiency became a concern, homes were not built to be weather tight. Insulation concepts were very basic. Walls and ceilings were made from much more porous materials. Thus, water vapor could easily flow in and out of walls. Today’s homes are much “tighter.” Windows and doors are built to reduce air leakage, and weather stripping, modern insulation, vapor barriers, and new construction techniques can help keep cold air out and lock moisture inside. As a result, moisture from bathrooms, kitchens, and doing laundry can result in higher interior relative humidity. In the worst conditions, this can build up to excessive, even harmful, moisture levels.

Does the amount of condensation depend on the window type?

Bay or bow windows usually experience more condensation than other window styles. This is because inside air circulation around these window styles is usually more restricted. And, since they hang away from the insulated house wall, bays and bows are usually a few degrees cooler in temperature. To help control excessive condensation, it’s smart to insulate between the window head and platform. In extremely cold climates, additional insulation above and below the window platform may be needed. As a secondary measure, placing a common electric fan near the window helps promote air circulation and can reduce window condensation.

How do drapes and window shades affect window condensation?

Drapes and other window coverings can contribute to a condensation problem by restricting the flow of warm room air over the glass surface. Therefore, indoor condensation is more apt to occur when the drapes are closed or the shades are pulled down.

Can excess condensation damage windows?

Excess window condensation can cause paint to peel from the sash. Excess moisture can also damage the window frame.

Source:  Andersen® Windows

 
 
Footer