Condensation on Vs in the Glass

Have you ever noticed condensation on your windows before? It’s not uncommon, especially on cold days here in the Puget Sound region. Condensation on your glass doesn’t mean the glass has failed though. It just means the insulation value of the window is struggling to keep up with the demands. If you only notice this on very cold days a few times a year, it’s probably not something you should worry about. Now, if you see water on the glass, but can’t touch it with your finger, that’s likely a problem.

(This photo shows the two layers of glass with the space between for the insulating gasses)

I’ll touch briefly on how a window works. Typically, there are 2 layers of glass that are glued together with a space between them. That is what we call the IGU or Insulated Glass Unit. In that space, they trap gas inside to give the window it’s insulation value. Basically, the gas is the insulation, much like that pink stuff in your walls, attic, and crawl space.

Over time, the adhesives used to glue the two glass pieces together can fail. This will allow the gas to escape and air to enter the space between the glass pieces. A crack or hole in either piece of glass will cause this problem also. Since there is almost always some moisture in the air, that moisture gets between the two pieces of glass, and you will end up with condensation inside the IGU. This is a problem, not only because it looks bad, but the window has lost its insulation value also. These Insulated Glass Units should be replaced, which can usually be done without having to replace the window. Contact your local window repair specialist for more on that.

(This photo shows the two layers of glass with the space between for the insulating gasses)

If the condensation is on the glass and you can touch it with your finger, you’ll probably be okay. More than likely the IGU is struggling to keep up with the demanding temperature difference between the inside and outside of your home. This is not uncommon in older homes, especially on cold days. If you experience this issue frequently during the fall and winter months, you may want to start thinking about new windows. New windows will have better insulation value which will prevent most condensation build up.

Sometimes condensation will become visible when there is a lot of moisture inside the home. If you are boiling a lot of water your kitchen, for example, the windows in that area can start to build up condensation. The same thing can happen in a bathroom with a hot shower running. It’s best to open a window or turn on an exhaust fan in these situations. That will help pull the wet air out and allow the inside humidity to drop. Leaving your blinds up slightly will help also, that will let the air get to the window a little easier.

Condensation itself is not usually an issue, but it can be a symptom of something else that’s going on. If it happens frequently, we suggest looking into more energy efficient windows. If it only happens occasionally, it’s probably nothing to worry about.