There are quite a few signs that your existing windows may need to be replaced. These signs can be subtle at first, but may grow to become a major problem in your house.

How do I know when it’s time to change my windows?

One of the most common signs that your windows have reached the end of their service life is condensation forming between the panes of glass. Most modern windows are filled with an inert gas that reduces thermal conduction, such as Argon, or Krypton. When the seal of a window fails, it allows the gas to escape reducing the energy effectiveness, and allowing moisture into the window.

Another common sign of a window that has reached the end of its lifespan is a draft coming from the frame. All operating windows have weather stripping between the sash (the part of the window that holds the glass), and the frame. If that weather stripping becomes worn, cracks, or falls off all together, you will experience a draft in your house. The easiest way to detect the location of the draft is to hold a feather up to the window and move it around. Once the feather begins to flutter, you have detected the area where the leak is coming from. Below is an example of wool pile weather stripping that had been damaged, and is partly missing, allowing a leak.

It is also typical for windows to have caulking around the outside of the frame, or brick mould. This caulking will shrink over time, and eventually crack, which will allow moisture into your home. A quick visual inspection of the surroundings of each window’s exterior can determine the state of the caulking. Cracked caulking is not necessarily an indicator that your windows need to be replaced, but it should be addressed before any damage can be done to your building envelope.