The seasons can change quickly here in New Mexico, and when that first cold snap hits is when we start getting calls about replacing foggy windows. The windows fog up and water drips down the glass. Don’t worry, this is not and indication that your windows have failed. It may be an indication that you have old windows! The moisture on the glass is condensation; a natural occurrence that in most cases can be eliminated. Condensation occurs when excess humidity in the air comes up against a cool surface. The glass in windows and patio doors provides a cooler surface that can show the first signs of condensation. Usually the windows affected are in a bedroom, kitchen, or living space where people spend a lot of time. It’s the same reason you have moisture on your bathroom mirror after a hot shower. When you open the door and let cooler air in, the fog disappears. With windows the same problem can usually be corrected by increasing the air flow in the room.
Homes that are built today are more energy efficient and more air-tight than homes built even a few years ago. Because of this there is less exchange with outside air. This saves energy, but tends to increase interior humidity. Because the humidity levels inside the home tend to rise, you may notice condensation in your new home that you never had in your old home.
Older homes with newer windows may experience condensation due to increased efficiency. Old windows allowed a lot of air exchange with outside, allowing the inside air to dry out. New windows are installed in an airtight manner, which is great, but it traps humid air inside. An easy way to reduce the humidity is to open the windows or doors. Of course, when it’s cold outside that’s not something you want to do! If you open some windows or doors in the house around midday and let some air flow through, that will reduce the amount of humidity the next morning.
Why is there so much humidity? Family lifestyle has the most impact. Cooking meals, long showers or baths, even washing clothes all contribute to humidity levels. Variations in these and other moisture generating activities or products (like a humidifier) can result in one neighbor experiencing condensation and another not.
What can you do? Controlling indoor humidity is the key.
• If you don’t already have new windows, consider installing a window that has a dual paned insulated glass unit. For further protection, we always recommend getting windows with an insulated glass unit that includes a Low-E coating. This coating on the glass reduces radiant heat-loss and the passage of ultraviolet rays. The better the Low-E the more it stops condensation. A ‘soft coat’ Low-E is the best.
• Having windows that include Argon gas between the panes helps out as well. Since Argon is an inert gas, and heavier than air, it makes a great buffer for heat transfer. Having windows that have both Low-E and Argon gas is the way to go for energy efficiency. Look for the Star. Energy Star rated windows will have an NFRC rating sticker that will tell you the efficiency ratings for the window.
• You can raise the temperature of your home. Even just one or two degrees can make a difference and greatly reduce condensation.
• Open your blinds or curtains for air circulation. Closed blinds or drapes trap warm air in the space between the glass and the blinds.
• Use a ceiling fan to move warm air toward your windows.
• For an unoccupied or unheated room, keep interior doors open to promote air circulation.
• Run the exhaust fans in bathrooms and kitchens.
• Make sure all vents and ducts are clear of lint and other obstructions.
Aluminum windows are especially subject to condensation because of the metals ability to transfer heat. The temperature of aluminum will quickly change to the air temperature around it. An aluminum window including a thermal break has a much lower chance of condensation. Vinyl windows are the least susceptible to the condensation phenomenon.
Condensation is a natural occurrence that happens on the exterior and interior glass surfaces. In nearly all cases, it is not the result of a defective window or patio door. Take steps to reduce humidity with proper air circulation and the problem should be solved! At Glass-Rite we build and install our state of the art Energy Quest Vinyl window. This window comes standard with high efficiency SolarBan 60 Low-E glass and Argon gas between the two panes. If you have foggy windows they may not be failed, but it may be time to think about replacing them with something more efficient. Please visit our shop and showroom or contact us to learn more!