What Causes Condensation on New Windows?

Condensation happens when warm, moist air comes into contact with a cooler surface, such as your window glass. This process causes the moisture in the air to cool and condense into water droplets. There are several reasons why this might happen:

1. Increased Energy Efficiency: New windows are designed to be more energy-efficient than older models. Features like double or triple glazing, low-E coatings, and advanced weatherstripping reduce drafts and keep indoor air tightly sealed. As a result, moisture-laden air from inside your home has fewer ways to escape, making condensation more likely on cool surfaces.
2. Higher Indoor Humidity Levels: Homes with high humidity are more prone to condensation. Activities like cooking, showering, and even breathing release moisture into the air. If your home’s ventilation isn’t adequate, this moisture can accumulate and settle on your new windows.
3. Cooler Exterior Temperatures: During colder months, the temperature difference between the inside and outside of your home increases. This temperature disparity can lead to condensation forming on the colder interior side of the glass.

How to Reduce Condensation on New Windows

While condensation isn’t harmful in small amounts, excessive moisture can lead to mold growth, damage to window frames, or an uncomfortable living environment. Here are some practical tips to reduce condensation:

1. Lower Indoor Humidity:
   • Use a dehumidifier to maintain optimal indoor humidity levels (30-50%).
   • Run exhaust fans in kitchens and bathrooms during and after cooking or showering.
   • Avoid overwatering houseplants or drying laundry indoors.
2. Improve Ventilation:
   • Open windows occasionally to let fresh air circulate.
   • Use ceiling fans to distribute air evenly throughout your home.
   • Ensure vents and air ducts are unobstructed and functioning properly.
3. Maintain a Comfortable Indoor Temperature:
   • Keep your thermostat at a consistent temperature to minimize fluctuations.
   • Use insulated curtains or blinds to keep window surfaces warmer.
4. Upgrade Ventilation Systems:
   • Consider installing a heat recovery ventilator (HRV) or energy recovery ventilator (ERV) to exchange stale indoor air with fresh outdoor air while retaining heat.
5. Use Window Treatments Wisely:
   • Ensure curtains or blinds are not completely closed, especially at night, as this can trap cooler air near the windows, increasing condensation.
   • Opt for breathable materials in window coverings to allow better air circulation.
6. Address Structural Factors:
   • Check for potential leaks or sources of excessive moisture around windows or walls.
   • Ensure your home’s foundation and crawl spaces are well-insulated and free from water intrusion.
7. Consider Behavioral Changes:
   • Limit activities that produce excessive moisture, such as boiling water for extended periods without a lid or taking extra-long showers without ventilation.
   • Ensure kitchen appliances like stoves and dryers are vented to the outside.
8. Add Absorptive Products:
   • Use silica gel packs or moisture-absorbing products near windows to help reduce condensation naturally.

When to Worry About Condensation

Not all condensation is normal. If you notice moisture between the panes of your double- or triple-glazed windows, this indicates a seal failure, and the insulating gas has likely escaped. In this case, contact your window manufacturer or installer for repair or replacement under warranty.

Another red flag is persistent condensation leading to damage such as mold, mildew, or peeling paint around the windows. These issues can affect the indoor air quality and structural integrity of your home, so it’s important to address them promptly.

Additionally, excessive condensation over time can lead to rotting wooden frames or compromised window seals. If you notice unusual odors, warped wood, or peeling finishes around your windows, it’s time to consult a professional.

How to Prevent Future Issues

Preventing condensation requires a proactive approach to managing humidity and ventilation. Here are some long-term strategies to keep your windows and home in excellent condition:

1. Upgrade Insulation:
   • Ensure walls, ceilings, and floors are well-insulated to minimize cold spots where condensation is likely to form.
2. Monitor Humidity Levels:
   • Use a hygrometer to keep an eye on indoor humidity and make adjustments as needed.
3. Regular Maintenance:
   • Clean windows and frames regularly to prevent buildup of dirt and moisture.
   • Inspect window seals and caulking for any signs of wear or damage.
4. Consider Window Upgrades:
   • If your windows are older, consider upgrading to models with advanced condensation-resistant technology, such as double or triple glazing with argon gas fill.
5. Seal Gaps and Cracks:
   • Ensure all gaps around doors, windows, and vents are sealed to prevent outside air from entering and exacerbating temperature differences.
6. Install Weather Stripping:
   • Apply weather stripping to windows and doors to enhance their insulation and reduce drafts that might cool surfaces unnecessarily.

For dealers looking to provide helpful material to homeowners about condensation, download our handy condensation guide here!