subject: Condensation On Windows--12 Low-cost Or No-cost Solutions [print this page] What causes window condensation? Usually it's not your windows--unless they're doing their job too well.
The real enemy is invisible water vapor floating in the air of your home. If there's too much of it, and your windows become cold (below the ambient "dew point") from the exterior temperature, it will condense on them. This can happen even with the most expensive, brand new, ultra-high-performance windows.
As we've gotten better at keeping drafts out of our houses, we've also stopped fresh air getting in, and stale, moisture-laden air getting out.
Twelve Solutions
Before you bring in expensive experts to solve your window condensation problem, try these 12 low-cost or no-cost alternative solutions:
If you're expecting a particularly cold night, open some of your doors and windows for a few minutes late in the afternoon to clear out the excess water vapor that's built up during the day.
Consider rescheduling activities that create the most airborne moisture--such as showers, baths and clothes drying--to times of day when the outside temperature is warmer.
Fit exhaust fans in your kitchen and bathrooms. These areas are major sources of the excess moisture that can build up in your home.
Remember to turn those fans on when they're needed! If you have any, open the flaps (the ""dampers"") in the chimneys above your fireplaces to allow excess water vapor out.
Vent your clothes dryer so that the moisture it creates goes outside.
Do the same with any gas burners you have.
Consider buying a hydrometer. These start at about $20, and can help you track and understand the factors that are affecting your moisture levels.
Make sure that the louvers that are supposed to ventilate your house (usually in your crawl spaces/basement and attic) are fully open and not obstructed.
If they're open and unobstructed, but not doing their job, consider replacing them with larger ones.
Turn off all humidifiers. They're really, really not helping.
If possible, avoid burning gas (including propane) because this--in all forms--releases very large quantities of water vapor.
There's a very good chance that these simple, inexpensive steps will fix your issues. But if, after a few winter weeks, they haven't, do call in the experts. Over a period, window condensation can cause real damage to your home.
