As temperatures drop across North Dakota, homeowners often notice moisture or “sweating” on their windows. While this can look concerning, condensation is usually not a sign of faulty windows — it’s a natural result of high indoor humidity meeting cooler glass surfaces.
Modern, energy-efficient windows are designed to seal your home tightly. This helps keep heat inside and drafts out, saving energy and improving comfort. However, that same tight seal also traps indoor air — and with it, moisture from cooking, showering, laundry, and even breathing. When humidity levels rise, that moisture collects on the coldest surface available: your windows.
Common Causes of Indoor Moisture
Condensation is caused by excess humidity inside your home. Everyday activities like these add moisture to the air:
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Cooking, dishwashing, and boiling water
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Hot showers or baths
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Using dryers that aren’t vented properly
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Running humidifiers
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Having many houseplants, aquariums, or pets
A little humidity is healthy, but too much can lead to persistent condensation, mold growth, and even damage to paint or wood surfaces.
When Condensation Is Temporary
You may notice temporary condensation:
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At the start of heating season (when your home “dries out” from summer humidity)
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During sudden drops in temperature
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After showers, laundry, or cooking
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During new construction or remodeling (as building materials release moisture)
If condensation disappears once temperatures stabilize, it’s typically nothing to worry about.
When Condensation Becomes a Problem
Persistent moisture may indicate chronic high humidity in your home. Take action if you notice:
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Water on windows throughout the day
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Moisture or staining on walls and ceilings
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Peeling paint or wallpaper
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Musty odors or visible mold
If condensation appears between the glass panes, that could mean a seal failure — which is covered under your window warranty. Contact us right away for service.
How to Reduce Condensation
The good news? You can manage indoor humidity easily with a few adjustments:
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Reduce moisture sources – Use exhaust fans when cooking, showering, or doing laundry.
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Improve air circulation – Keep blinds open, use ceiling fans, and make sure air vents aren’t blocked.
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Control humidity – Maintain humidity between 20–35% in winter, depending on outdoor temperature.
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Add ventilation – Use a dehumidifier or crack a window briefly to balance indoor air.
💡 Pro tip: The colder it is outside, the lower your indoor humidity should be. For example, at 0°F outdoors, your indoor humidity should be around 20–25%.
🏠 Ideal Winter Humidity Levels
| Outside Temperature | Recommended Indoor Humidity |
|---|---|
| -20°F | 15% or less |
| -10°F | 15–20% |
| 0°F | 20–25% |
| +10°F | 25–30% |
| +20°F | 30–35% |
Keeping humidity within this range helps prevent condensation and protects your home’s comfort, structure, and air quality.
Healthy Home, Happy Home
Balancing temperature and humidity doesn’t just protect your windows — it also improves your indoor air quality. Proper humidity prevents mold, mildew, and bacteria growth while keeping your home more comfortable year-round.
📄 Download our full Humidity & Condensation Guide for detailed recommendations and troubleshooting tips:
👉 https://www.thewdstore.com/wp-content/uploads/2025/11/humidityandcondensation.pdf
🪟 The Window & Door Store — helping North Dakota homeowners maintain energy-efficient, comfortable homes in every season.
