Understanding and Preventing Window Condensation

Condensation is frustrating and can make you wonder if your new or replacement windows are in need of repair or replacement. You may see a few water droplets or it might look like a river is running down the glass. Either way, let’s face it – looking out your window and seeing water on the inside or outside of the glass is not the view you had in mind when you purchased your home. If you are like me you don’t care about the science behind condensation, you just want it gone! However, taking a few minutes to understand why your replacement windows have condensation will go a long way in preventing it in the future.


Condensation happens when the moisture in your home’s air comes in contact with a surface that is cooler than the air temperature.

Much like how a cool beverage on a hot day collects condensation, your windows act the same.

cold air and old windows


If you have energy efficient replacement windows condensation could be a signal your window is working well or it could mean your windows are in need a replacement. How can you tell the difference?

If from time to time you see small amounts of moisture that you can easily wipe away or it dries when the sun comes out, there usually is no need for concern.

If you see large amounts of moisture that may be damaging the wood trim or the moisture is between the panes of glass and can’t be wiped away this usually indicates a problem with the window or a performance design issue and you should call for service or start looking to replace your windows.


One of the quickest ways to reduce or eliminate condensation is to have your indoor humidity closer to what it is outside. With less moisture in the air you won’t see as much, or any, condensation.

  1. Purchase new or replacement windows that are designed to prevent condensation.condensation on an old window

Yes, this is a real thing! This rating is listed on the windows label as “Condensation Resistance”. Publishing this rating is optional so if your window doesn’t rate well, you may not see this published. According to the National Fenestration Rating Council (NFRC) the higher the number, the better it resists condensation.   All Ratings for windows can be found at nfrc.org.

  1. Keep the humidity in your home at the correct level according to the outside temperature. The American Architectural Manufactures Association (AAMA) provides a useful resource for determining this level.  The warmer the temperature, the higher the humidity can be without condensation.
  2. Use a dehumidifier in the cooler months and humidifier in the warmer months. If you have energy efficient windows with low-e, and inert gas, your windows will insulate better. This means during the winter when your furnace is running the inside of the window is warmer than the outside temperature. On the reverse, if you use air conditioning during the summer, the inside is cooler than the outside temperature.
  3. Run exhaust fans during showers and while cooking and leave them on for 10-15 minutes after your shower or cooking is completed. The use of showers and cooking releases large amounts of moisture in the air. Exhaust fans pull the moisture out of your home, helping to reduce your home’s humidity level.
  4. Don’t keep all your plants by the same window or move larger plants away from your windows. Plants naturally release moisture and having large groupings of plants near a window can cause the moisture released to collect on the windows


When shopping for energy efficient replacement windows it’s important to consider all factors. The combination of features you get with AHT Wisconsin Windows is how we are helping homeowners save up to 40% on their heating and cooling costs!

Buying replacement windows and doors is an investment you only want to make once and not all windows and window companies are created equal. That’s why selecting the right replacement window company is critical.

wisconsin replacement window company

Windows from AHT come with several features that help to reduce condensation.  Most companies use aluminum to separate their windows. Aluminum is cold and reduces the glass temperature increasing condensation.  Warm edge glass technology, or HEAT SEAL, is the spacing material between the panes of glass only used by AHT. This is nonconductive, or an insulator, that increases the glass temperature on the inside to reduce condensation.  22 layers of Low-e and Krypton gas is used to better insulate the glass pack, increasing the glass temperature reducing condensation. Combining these technologies, allows AHT windows to have one of the highest condensation resistance factors published by the NFRC.

When you put your trust in AHT Wisconsin Windows you also get the following benefits:

  • Solid Core Composite Frame with Triple Panes of Glass
    • Up to 400% stronger than rigid vinyl
    • Available in a variety of colors to fit every décor
    • Warm edge spacer system
    • 2 layers of proprietary Krypton blend gas fills
  • Superior Low-e Glass
    • Titanium low-e application: Most energy efficient and reduces up to 99% of damaging UV rays
    • Soft coat low-e application: Provides uniform coverage
    • 22 layers of directionally applied low-e coatings: Typical windows have 3-6 layers applied. Our 22 directionally applied layers allow passive solar heat during colder months and reflect solar heat during warmer months.
  • Energy Star Most Efficient Window 2019
    • We’ve been named Energy Stars most efficient window 5 years in a row!
  • 50-year Warranty
    • Hands down, the best warranty you’ll ever find!
    • Not prorated and fully transferrable.
    • Warranty for workmanship and product.
  • Experience and Reputation
    • We’ve been selling and installing windows since 1967 and have an A+ rating with the BBB
  • Testimonials, Reviews and Pictures
  • Options to Fit Every Budget
    • We have partnerships with a variety of lenders and our expert consultants will work with you to find a payment that is comfortable for your budget and make your home improvement dream a reality.

AHT Wisconsin Windows proudly serves the following areas: Appleton, Neenah, Madison, Clintonville, Fond du Lac, Green Bay and surrounding areas. Call AHT Wisconsin Windows today at 866-367-6560 to find out if we service your area.