American Exteriors LLC : Understanding Window Condensation

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American Exteriors LLC : Understanding Window Condensation

"I just replaced my windows with energy efficient vinyl windows from American Exteriors LLC and now I see condensation. What's going on?"

What causes window condensation?

How to control condensation on your windows.

Are My Windows Leaking?

Condensation on windows is not caused by the window. By replacing drafty windows, installing a new roof, or installing new siding you are reducing the air infiltration and uncontrolled air flow from the home to the outside environment making it tighter. Tighter homes will tend to retain more moisture requiring either an assessment of conditions that can be modified or systems to better manage moisture control.

What Causes Condensation on Windows?

In the winter, moisture generated by our activities combined with the lack of natural ventilation (open windows or the dehumidifying impact of air conditioning) will lead to high humidity levels. High humidity levels within the house can cause moisture to condense on windows.

This information will help you maintain proper humidity levels in your home. A central humidifier can be used to prevent the house from "drying out" due to furnace operation and relatively dry outside conditions. This may be necessary in order to protect furnishings, building materials and even health. If winter humidification is employed, it must be controlled in order to avoid potentially damaging and even unhealthy excess humidity. Either a dehumidifier or HRV can be used to lower humidity levels.

Factors such as closed blinds or drapes may require you to decrease the relative humidity in your house as this could trap moisture. A good rule of thumb for controlling relative humidity in the winter: if frost or condensation forms on your windows, the humidity is too high and you should turn down the humidistat. You may need to regularly adjust the humidistat setting and the HRV setting (if you have one) to properly control the humidity in your house.

How Can I Control Condensation On My Windows?

In general, the two things you need to do to reduce humidity are:
1) Control sources of moisture
2) Increase Ventilation.

Here are a few suggestions to consider in order to do so.

•Operate your bathroom exhaust fan during baths and showers and for an additional 30 minutes or longer after bathing or showering to remove moisture from the room.

•Operate the kitchen exhaust fan when you are cooking.

•Vent gas burners and clothes dryers to the outdoors (run a dehumidifier if you hang clothes indoors or avoid this practice in the winter months).

•Be sure that louvers in your attic, basement and crawl spaces are open and properly sized.

•Check for proper grading around the foundation to reduce moisture from entering the house through basement walls.

•Open blinds during the day.

•Maintain a clean furnace filter.

• Run your furnace fan continuously in the "ON" position of your thermostat- this practice has a low cost and will allow for a more even temperature throughout the structure. Additionally, "moving" air will tend to hold more moisture than stagnant air thus helping to prevent moisture from collecting on windows and other building materials. Continuous fan operation in connection with a bath exhaust fan also helps to prevent moisture generated in the bathrooms from being distributed through your ductwork to the rest of the house.

•Inspect for and eliminate plumbing leaks.

•Control or cover any other sources of humidity (radiator water pans, fish tanks, large numbers of plants, etc.)