Why Do I Have Condensation on the Inside of My Windows?

Why Do I Have Condensation on the Inside of My Windows?

Picture of condensation on windows.

“Why do I have condensation on the inside of my windows?”

This is a common question we hear from homeowners who are considering window replacement or have recently had windows replaced. Window condensation can be irritating and worrisome. Condensation can be damaging to items in your home such as wood windows, wood molding, and plaster.

However, as odd as this may sound, having condensation on the inside of your windows actually indicates that your windows are working as they should. In fact, once old windows are replaced with new quality windows, condensation might be more noticeable than it was with your old drafty windows. We’ll explain this, but first let us explain what window condensation really is. 

What is Window Condensation?

Condensation is moisture in the air that deposits onto a cold surface. Cold air holds less moisture than warm air. When temperatures start to drop, warm air within your house comes into contact with cool glass surfaces. Water vapor that can no longer be held by the cooled air is deposited on the glass.

Windows do not cause condensation, they just happen to be the place where moisture is most visible because they are typically the coldest surface in your home.

Causes of Window Condensation

Condensation is most likely a sign of excess moisture or humidity levels in the home. There is humidity inside every home, and it is caused by a great number of everyday activities. Cooking, baths and showers, doing the laundry, running dishwashers, storing and burning firewood, pets, fish tanks, plants, clothes dryers that are not vented properly, and many other items contribute to indoor humidity levels.

The construction and insulation materials that are used in newer or remodeled homes are designed to keep cold air outside. This is especially true of new windows. New energy efficient windows will keep cold air outside, meaning that they also keep warm moist air inside.

Windows that are drafty or less energy efficient allow the warm moist air to escape. So, if your new windows are showing condensation more than your old ones, it is likely because they are more airtight – less air is entering your home from the outside. Your drafty older windows evaporated the moisture before it could collect on the window surface.

How to Reduce Window Condensation

To reduce condensation on your windows, you should reduce the humidity levels in your home. There are several steps you can take, including:

  • Using exhaust fans in bathrooms and kitchens
  • Turning off home humidifiers for the winter
  • Run a dehumidifier
  • Store firewood outside
  • Don’t air-dry clothes indoors
  • Open blinds and drapes
  • Purchase an indoor humidity monitor to maintain ideal levels 
  • Open a window for a short time 
  • Increase ventilation 
  • Increase the temperature of your windows
    • Single-pane glass windows allow for a much lower indoor humidity level than double pane windows. Consider replacing single pane windows with windows that have double-paned glass with a low-e coating and argon gas filling. This is not guaranteed to eliminate condensation, but at the least, it should significantly reduce it.

Interior window condensation is a clue that excess moisture is present and may lead to rotting wood and molding, deteriorating insulation, and other factors. Excessive indoor moisture or humidity are not the result of your windows, new or old.

If you are in the St. Cloud, Minnesota area and searching for a team for your door or window installation needs, contact Tony’s Lifetime Exteriors. Since 1973, we’ve provided our neighbors with the best customer service around, and have been exceeding expectations for years. Our licensed and certified contractors will help you develop a budget before ordering and installing your products of choice.

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