Windows bring you more than sunshine and a view of the outdoors. They also can help you protect your home and your health.

Foggy windows are a sign of indoor humidity that can eventually lead to costly problems, such as peeling paint, rotting wood, buckling floors, insulation deterioration, mildew, and even moisture spots on ceilings and walls. Here are some common questions about condensation:

Do Windows Cause Condensation?

No. Windows do not cause condensation. Windows are most often the first places where condensation can be seen.

What does cause condensation?

Condensation forms when warm, humid air contacts a cold surface. Moisture is in the air all around us. Warmer air can cause more moisture. As air cools it contracts and its moisture condenses.

When the temperature drops, the first place you will see any condensation is on the windows. Your windows are the coldest surfaces indoors. During colder months, indoor air is much warmer and holds more moisture than outdoor air, which is colder and dry. Warm humid indoor air cools and contracts as it contacts the cooler windows, and the moisture condenses on the glass. 

Why is indoor air so humid?

Everyday living - Showers, baths, cooking, washing dishes, doing laundry, and cleaning all add moisture to the air in your home, as much as four gallons or more per day in some homes. We even exhale moisture into the air as we breathe.

Home construction - Today's energy-efficient, well insulated homes help us hold down heating and cooling costs. But the same things that block outdoor air from entering our homes also keep moisture from venting to the outdoors.

How can humidity cause problems?

I thought it was good for your health.

It was once believed that winter use of humidifiers helped people stay healthy. But studies have shown this to be untrue, particularly for healthy people. Although manufacturers maintain that humidifiers can benefit plants and furniture, the Association of Appliance Manufacturers states that there is no evidence that humidifiers have any medical benefits.

What kind of problems?

Health problems - Mold and mildew thrive in moist areas with plenty of organic material, such as wood, plaster and some types of insulation. Many types of molds easily become airborne. When inhaled or ingested, molds are known to cause local or systemic allergic reactions, sinus and nasal irritations and infections, chronic respiratory problems, dizziness, lethargy, and trigger attacks in people with asthma.

Structural damage - Because humid indoor air tends to be under higher pressure than outdoor air, indoor air constantly pushes its way outward, to the area of lower pressure, right through wood, plaster, insulation, and concrete. This process can cause insulation to deteriorate, paint to blister and peel, unsightly stains on walls and ceilings, rotting of floors, wall supports and other structural supports, including foundation damage.

Is condensation more likely in certain climates, types of homes or windows, or times of year?

Yes, It's more likely to occur...

• In areas where January temperatures average 35 degrees Fahrenheit or less.

• In summer and fall, when homes pick up moisture from damp air.

• With sharp, quick drops in temperature, creating temporary condensation problems.

• For one year after construction or remodeling, while building materials dry out.

• On bay or bow windows, where air circulation is often restricted and windows tend to
  be few degrees cooler since they project out from the insulated house wall.

• When drapes are closed and shades are pulled down.

I have condensation on my double-glazed windows. How can I tell if it is from bad seals or indoor humidity?

Before calling for repair service, try this easy test.
Run your finger through the area where the condensation is formed. If your finger gets wet and leaves a trail through the condensation, it's on the room side of the glass. If your finger remains dry and leaves no mark in the condensation, the moisture is collecting between the window panes. This tells you that the seal in the window has somehow been damaged and needs repair or replacement.

I didn't have condensation problems with my old windows. Why now?

If your old windows were drafty, those cracks allowed excess moisture to escape outdoors (when the wind wasn't blowing in). Your new windows are better insulated, so indoor humidity can't escape.

Call Target Window & Door now for more information. Our toll-free number is 1- 800-956-7722.