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Have you noticed that the windows in your home are continually fogging up? Does it seem like they are collecting moisture? This isn’t necessarily your windows’ fault. In fact, window condensation may be an indicator of something entirely different.
No. Windows do not cause condensation. But, windows are often the first place where condensation can be seen. Think about it. You’re probably not surprised or concerned when your bathroom mirror becomes fogged. You expect it after a hot shower. Your car windows fog up in humid weather or in winter when you have several passengers. These are just a few examples. And although condensation usually occurs in cold weather, it can occur during humid months when the air conditioning is running. The mirror doesn’t cause the condensation. The car windows don’t cause it either. These are just the first places you actually see condensation. The same is true for the windows in your home.
Condensation forms when warm, humid air contacts a cold surface. Moisture is in the air all around us. Warmer air can hold more moisture. As air cools, it contracts (just as people pull their arms and clothing tight around them when chilled) and moisture condenses. When the temperature drops, the first place you will see any condensation is on the windows. this is because our 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.
The most common cause of indoor air humidity is everyday living. Things like 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. Indoor humidity can also be caused by 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.
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. That tells you that condensation is forming because of excessive indoor humidity. And here’s another tip. If more than one window is showing condensation, it’s extremely unlikely that the seals are bad on all of the windows. It’s probably indoor humidity.
If your old windows were drafty, those cracks did more than just let in the wind; they allowed excess moisture to escape outdoors. Your new windows are better insulated, so indoor humidity can’t escape. Windows do not cause condensation and, at the same time, can’t eliminate condensation.
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 – and there are thousands – easily become airborne (it’s often their means of reproduction). 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.
Set your humidifier at the level recommended below for winter temperatures:
INSIDE RELATIVE HUMIDITY
Indoor humidity can be checked with a humidity monitor or regulated with a humidistat, available at most building supply stores and home centers.
Yes. It’s more likely to occur: