As winter approaches, many homeowners face the problem of condensation building up on their windows and patio doors. Oddly enough, much of the problems associated with condensation stem from advancements in building technology. If you’re having trouble with window condensation, the chances are that you are living in what is called a tight house. This is a house that cannot adequately breathe and moisture is trapped inside. Although older homes may actually cost more to heat, the house is more breathable, cleaner and more comfortable.
A little fog on the lower corners or window portions during the winter months is of little concern, but the excessive fog that blocks whole windows is a major headache. The excess water can run down and damage woodwork, wallpaper, paint or plaster. It’s a problem you should pay attention to and take very seriously. Noticing it on your windows or patio door is enough for concern, but you should be more worried about where you can’t see the condensation buildup. This excess humidity may be affecting the insulation in your attic whereby it freezes and then melts when warm weather comes. It may even be forming blisters beneath your siding and under your exterior paint.
All forms of water such as humidity, water vapor, moisture, and steam are present in varying degrees in nearly all air. The moisture in wet air tries to flow toward drier air and mix with it, which scientists describe as vapor pressure. Vapor pressure can act independently of the flow of the air. It can force moisture easily through wood, plaster, brick and cement. Vapor pressure is precisely what happens when moisture seeks to escape from the humid air usually found inside your home to the drier winter air outside.
Glass is one of the building materials that stop water vapors and vapor-seal insulation. It is designed specifically to stop the escape of water vapor and protect the insulation and your walls from the ravages of water. However, increased use of these moisture trapping materials has created the modern “tight” home where moisture created by bathrooms, kitchens and laundry rooms can no longer flow easily to the outside. This trapped effect keeps cold air outside and moisture in, so it is very easy to build up excessive and even harmful moisture levels in a home.
How to Reduce Humidity
David Bareuther, Associated Press Building editor states that there are only three ways to reduce humidity:
- Get to the source: Venting all gas burners, clothes dryers, etc., to the outdoors, including the use of kitchen or bathroom exhaust fans.
- Ventilation for winter: Since outside air usually contains less water vapor, it will dilute the humidity of this inside air. This takes place automatically in older houses through constant infiltration of outside air.
- Heat: The process of heating your home will reduce the relative humidity, providing its dry heat. It will counter-balance most of the moisture produced by modern living.
To test the humidity in your home, be sure to use an accurate instrument like a sling psychrometer.
|Outside Air Temperature||Inside Relative Humidity
70 F Indoor Temperature
|-20 degrees F or below||not over 15 percent|
|-20 degrees F to -10||not over 20 percent|
|-10 degrees F to 0||not over 25 percent|
|0 degrees F to 10||not over 30 percent|
|10 degrees F to 20||not over 35 percent|
|20 degrees F to 40||not over 40 percent|
Here are 7 practical steps to control condensation on your windows or patio door.
- Install storm windows or replacement windows with double or triple glazing.
- Shut off furnace humidifier and any other humidifying devices in your home.
- Be sure that louvers in attic or basement crawl spaces are open and that they are large enough.
- Run kitchen or other ventilating fans longer and more often than has been your custom.
- Open fireplace damper to allow easier escape for moisture.
- Air out your house a few minutes each day. Air out kitchen, laundry, and bathrooms during use or just the following use.
- If troublesome condensation persists, see your heating contractor about an outside air intake for your furnace; about venting of gas-burning heaters and appliances; or about the installation of ventilating fans.
Because of so many variables, a condensation problem can sometimes be very tough to solve and that’s why you may have to call in an expert to work on your problem if the simpler steps to reduce humidity doesn’t work. If you feel that the problem might be caused by your windows or doors, contact us and our team will be ready to help.