Window Condensation: What It Is and How to Prevent It

Condensation on windows can be harmless, but it can also be a sign of an underlying problem. This process occurs when warm air touches a colder surface, causing water vapor to turn into liquid.

When condensation occurs on the outside surface of the interior windowpane, it means that the room is so airtight the moisture can’t escape. While airtight windows are a good thing, these water droplets can damage building materials.

When panes fog up inside, it’s evidence of seal failure. The moisture begins to take the place of the insulating gas inside the glass unit, which generally requires window replacement.

How to Prevent Each Type of Window Condensation

Exterior Condensation

• Vent Moisture-Ridden Air – Since exterior window condensation results from excessive indoor humidity, expelling too much moisture in the inside air is the key. You can ventilate the room through natural or mechanical means to get rid of the wet air.

• Dehumidify the Room – Another option to moderate the amount of moisture in a humid environment is the use of a dehumidifier.

• Choose Energy-Efficient Windows – When tackling window replacement, look for products with low-emissivity coatings, an argon gas fill and a warm-edge spacer. These features work together to keep the glass surface warm enough to inhibit condensation.

Interior Condensation

• Buy Thoughtfully Designed Windows – Choose double-pane windows that were sealed with excellence. At Renewal by Andersen of Portland, we use two specialized sealants; the primary one renders the glass barrier airtight, and the secondary one helps keep the spacer stable. We remove the multiple layers of low-emissivity coats around the glass edge to create clean surfaces for proper sealant adhesion. We’re so confident that the organic seal of our products won’t break long after window replacement, we offer a 20-year warranty covering this issue.

To learn more about how our windows resist condensation effectively, call (503) 419-3960 to schedule your FREE consultation and choose your own time and date. We serve Portland, OR, Vancouver, WA, and nearby communities.