Condensation on your windows can be an annoying surprise—especially in a brand-new home. Many homeowners worry that foggy or "sweaty" windows signal a defect, but in most cases, the windows are doing their job. They’re acting as a messenger, letting you know it’s time to take a closer look at your home’s humidity levels.
In this article, we’ll walk through common questions about condensation, how to manage indoor humidity, and what to watch for to protect your home from moisture-related damage.
Modern homes are built to be energy-efficient, with airtight construction that keeps warm or cool air inside. But this airtightness also means that moisture has fewer places to escape. When the temperature outside drops, moisture trapped indoors tends to show up on the coldest surfaces—typically your windows.
Contrary to what many assume, condensation usually isn’t a sign of poor window performance. Instead, it indicates high indoor humidity and inadequate ventilation.
Occasional moisture on your windows—like after a hot shower or when boiling water—is usually harmless and will disappear quickly. But persistent condensation, especially if it turns into droplets or drips, can lead to serious issues such as
That’s why it’s important to reduce excess indoor humidity before it becomes a bigger problem.
Moisture inside your home comes from a surprising number of everyday activities:
In fact, a family of four can generate up to 18 gallons of water per week just from daily living.
Newly built homes are also particularly prone to condensation. That’s because construction materials like wood and plaster release moisture over time—often taking up to a year to fully dry out.
The key to managing condensation is balancing moisture and ventilation. Here’s how you can reduce excess humidity:
While a little humidity can make winter air feel more comfortable, too much is never a good thing in modern, airtight homes.Below are general guidelines for indoor humidity based on the outdoor temperature:
Note: Sustainable 9 leaves a humidistat in every home we build to help monitor these levels. If you don’t have one, reach out to us or check Amazon—affordable options are available. We recommend placing one on each level of your home.
If condensation issues persist, consult an HVAC professional. You may need additional ventilation systems or adjustments to existing appliances.
Sometimes, condensation is just temporary. Two common causes include:
In both cases, you’ll see less condensation over time.
If you notice condensation between panes of insulated glass, that’s a different issue. It usually means the seal on your window has failed, allowing moisture inside. In this case, contact the window manufacturer for warranty service or repair.
Condensation is often misunderstood, but managing it is all about keeping indoor humidity in check. A little awareness—and a few ventilation upgrades—can go a long way in keeping your home comfortable, efficient, and healthy.
Got questions about humidity in your home? We’re here to help.
