Condensation

By, Craig Osterhoudt

Many of my customers ask the following question, especially during the winter. . .  

My windows get a lot of condensation during the winter. Is there anything I can do to help? Everyone says to buy replacement windows, but will that really solve the problem? 

This question, unfortunately, doesn’t have a simple answer and can’t be brushed off to some FAQ page, so I figured I would write this article, so I can refer people to it in the future and hopefully answer all of your questions when it comes to condensation. First thing to remember that in most cases condensation is a normal, everyday occurrence and you shouldn’t worry about it too much. Condensation occurs when the outside temperature is drastically different from the inside temperature and there is a high level of humidity in the room. The bigger the difference in temperature, the less humidity you need in the room to cause condensation. 

However, sometimes high interior humidity can cause damage to your home, such as drywall and wood rot and health hazards such as mold growing. What’s even worse is this can occur behind the walls where you never see it. If you have excessive levels of condensation in your home, you really need to address it.  

Another frustrating problem is that sometimes you have two houses, exactly the same in construction and location but different levels of condensation. This is due simply to f amily habits and occupants which have a large impact on humidity levels. Cooking, long showers or baths, saunas, spas, and washing/drying clothes all contribute to humidity levels. Someone who eats out and lives alone will have lower humidity levels than a family of eight, who boil large buckets of pasta at all three meals. 

Your first line of defense is to control your humidity levels, especially during the winter. You need to make sure you have good air flow throughout your house. Make sure vents aren’t blocked and interior doors remain open. It’s also recommended to use a ceiling fan, remember ceiling fans don’t make your home colder, they just circulate the air that’s there, regardless of the temperature. A low setting on your ceiling fan may actually help you feel warmer in the winter, remember warm air rises. You should also open your blinds; this allows the air trapped behind them to circulate easier into the room. 

You also need to check all appliances and make sure they are vented to the outdoors. Check dryer vents and such to make sure they are free from debris. If you have condensation problems, you should run your exhaust fans at least 15 minutes after you use the humidity creating device (shower, stove top) and you may want to consider running it for 5 minutes before you use the device as well. In extreme cases you can add an air-exchange system to your current heating system to reduce condensation. See your HVAC professional for more information. 

When it comes to replacement windows, they can have a dramatic effect. You see, if you currently have aluminum windows, they could be 90% of your problem. Aluminum itself attracts a lot of condensation because of how efficiently it transfers heat. The temperature of aluminum will quickly change to the air temperature around it. The colder the outside temperature, the colder the aluminum window frame and therefore more condensation will build up on your windows. 

Replacing those aluminum windows with vinyl windows, or any replacement windows that aren’t aluminum will cut down on condensation immediately, and sometimes this is your only option. Fortunately window replacements can pay for themselves within 3 to 5 years just from energy savings, especially in extreme weather regions. They also add to the value of your home. Sometimes in rare cases however, replacing your windows will cause condensation to appear where it didn’t accumulate before. This is because new windows are so much more energy efficient; humid air, that used to pass freely between your old drafty windows and the outdoors, can now get trapped inside. 

As an endnote, the most important fact to remember from this article is that condensation is a humidity problem, not a window problem. If you have excessive condensation in your home you need to address your humidity levels first, get that under control and then address your windows after your humidity levels are under control.