We seal our homes as tightly as possible during winter to keep the cold from infiltrating our warm spaces.
This can create a problem of its own in the form of condensation on windows, walls, and ceilings. But a build-up of condensation that never fully dries creates prime conditions for mold or mildew to grow.
Fight these mold and mildew conditions with our condensation guide.
What Causes Condensation on Windows?
Condensation builds up on windows due to excess moisture inside the home. Just like a hot day causes condensation on the outside of an icy cold glass, cold temperatures outside can cause condensation on our windows inside.
Ironically, the tighter the home, the more likely condensation will be an issue. With most moderately tight homes that have double-pane windows, you can maintain a relative humidity (RH) level of around 50-55 percent without much danger of condensation. However, if your relative humidity rises above that range when temperatures drop to about 40 degrees F, condensation becomes a problem. This can be especially true for condos and townhomes.
Even in areas of the country that don’t see severe winter conditions or where outside humidity is usually low, interior window condensation can still be a problem. So, where is all of this moist air coming from?
Sources of Humidity
It’s surprising how many ordinary things can increase humidity in our homes; fortunately, the solutions can be just as simple. Let’s look at some common causes of excess moisture in our homes and how to reduce it.
Commonplace Activities
Some of the most routine activities can cause RH levels in our home to rise during the winter months. Showering, cooking, using the dishwasher, exercising, and breathing usually all add moisture to our indoor air. We can’t exactly stop breathing, but we can establish some simple habits to help diminish all this moisture.
- Lowering the thermostat from 66 to 68 degrees F will create a closer balance between indoor and outdoor temperatures, saving energy and money.
- Make sure to use the bathroom fan while showering and allow it to run for 10 to 15 minutes afterward so all steam is vented outside the house. If you have an older home without a fan, consider installing one — usually a DIY project.
- The same is true when using the washer and dryer (make sure it’s vented outside), or ironing. If you have a big family and do laundry daily, you could even install a small exhaust fan in your laundry room to help remove humid air.
- Since burning gas produces moisture, ensure all gas appliances are vented properly and functioning properly. This is also a good idea from a safety standpoint.
- A ceiling fan in the kitchen, exercise room, or rooms with a fireplace will help increase air circulation and dissipate excess moisture.
- A fan-forced space heater is also an excellent way to increase air circulation and add warmth to your home.
- Open windows for a few minutes daily, especially after moisture-producing activities.
Inside Your Home
Using insulated drapes or curtains can contribute to additional condensation since they hold moisture and limit airflow. Open drapes or shutters during the day so windows are exposed to circulating air.
For those who prefer a wood-burning fireplace, be aware that storing firewood inside can also increase RH. Even seasoned wood will still have some retained moisture. And if you bring unseasoned wood indoors to dry out, the moisture released through this process can raise your indoor humidity level.
Structure Related Sources
Several issues related to the structure of your home can cause condensation:
- New Home Construction: A new home or a recent addition goes through a “drying out” period lasting 12 to 18 months. As soon as the heat goes on, moisture is released inside.
- Humid Climates: If you live in a more humid climate or have been through a particularly wet summer and/or fall, the same happens when temperatures drop, and you begin using your furnace or heating system. The solution is also the same, or if your climate is very humid, a residential dehumidifier will help reduce indoor moisture.
- Patios: Glass patio doors can form condensation, especially if a curtain covers them. Bay and garden windows can also contribute to increased humidity and window condensation since they create more area and extend further into cold air. Heat vents beneath them are the best solution, but increasing air circulation using a register booster fan will help if your home doesn't have one.
- Basements: Basements can also be a source of additional damp air. A simple solution is to run a dehumidifier in your basement space to reduce RH and help control musty odors and mildew or mold.
- Foundation Issues: For homes built on a concrete slab, moisture from the ground can seep into your home. Use a ceiling fan or fan-forced space heater to help with this, or open windows briefly to release humid air. If your home has a dirt crawl space, consider venting or covering it with a vapor-proof barrier to prevent moisture from rising into your home. Air exchange fans are ideal for venting various spaces in your home.
In Summary
Staying cozy and warm during the winter doesn’t have to mean dealing with damp windows and walls. The key is to keep indoor air moving, especially after moisture-producing activities, to address any structural sources of dampness, and ensure appliances and fireplaces are all vented and working correctly. So go ahead and snuggle up with your favorite hot beverage and let the wind blow.
Questions?
If you have further questions or would like help finding the right product to help solve your window condensation problem, please call our customer service team at 1-800-934-9194.
