DIY – Stopping Window Condensation



A common homeowner problem during late October and well into November is window condensation. There can be several causes as well as several possible fixes. At the root of the problem is too much humidity inside the home. Glass windows are the coldest surface in a home and act as a type of dehumidifier. This commonly happens when outside temperatures fall below 40o F.

Condensation happens in newer homes as well as older homes. Double and even triple insulated windows are not immune. In fact, newer homes can have more window condensation because these homes are sealed tighter to keep the cold out but keep the humidity in at the same time. Most homes with double pane windows will not have condensation problems if the inside relative humidity remains below 50 to 55 percent. When the relative humidity inside rises above 60 percent, cold windows act as a dehumidifier by condensing moisture until the level is again down around 55 percent or lower.

Simple Window Condensation Fixes

Start with a hygrometer. This is a small handheld device that measures relative humidity. These typically cost less than $20. You may be able to simply remove sources of humidity in your house until the hygrometer tells you the moisture level is consistently below 55 percent. Of course, you could skip the hygrometer and just remove sources of humidity until condensation stops forming on the windows.

An often over looked source of moisture are natural gas and propane fireplaces or heaters. Burning propane and natural gas releases a lot of moisture into the house if it doesn’t escape up the chimney. You can use these heat sources less or make sure the chimney is working efficiently to stop window condensation. One source that you can’t do much about is a newly constructed home that is built with moisture retaining materials such as wood and concrete. It takes 12 to 18 months for these to adequately dry out. In the meantime, you can occasionally crack open a window or two for 10 to 15 minutes to allow the humidity to escape the house. Running externally vented kitchen and bathroom fans also helps.

Another common problem is green houseplants. During winter months, you might want to move these into a seldom used room that is closed off from the rest of the house. Another possible source is excess ground water that continues seeping into concrete foundation and finds its way into the interior of the house. You can talk to your local building inspector about moisture problems common to your area but often these require a professional fix.

More Complex Condensation Fixes

Double and triple pane windows don’t remain sealed forever. The spaces between the panes are filled with argon or krypton gases. These windows are double sealed. The outer seal typically fails first but the gas remains sealed in until the inner seal fails. Unfortunately, these seals can’t be repaired. Generally, you have two choices, either replace the windows or bore tiny holes into the windows to vent the moisture out from between the panes. Neither is easy or simple and often best left to professionals.

Unfortunately, most window professionals don’t want to bore a vent hole into existing windows. Window installers prefer to sell you new windows instead. The truth is, boring a hole in windows causes them to lose much of their insulation value but it does get rid of the fog and condensation problem. What is involved is boring a small hole (2mm), spraying in a cleaning solution, allowing the solution to dry and installing vents in the holes. If you don’t want to do this and can’t find a professional to do it, your other choice is replacing the windows that have condensation. At least replacing the windows will restore the insulation value.

Please leave a comment about your own DIY projects and experiences or if you have questions/comments about this article.

Author bio: Brian Kline has been investing in real estate for more than 35 years and writing about real estate investing for 10 years. He also draws upon 30 plus years of business experience including 12 years as a manager at Boeing Aircraft Company. Brian currently lives at Lake Cushman, Washington. A vacation destination, a few short miles from a national forest. With the Pacific Ocean a couple of miles in the opposite direction.

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