Every year at this time we receive several calls from homeowners concerned about their cold, wet windows. They are understandably nervous that water is damaging the structure of exterior walls, or rooms are difficult to keep comfortably warm, or both.
It is not always easy to provide accurate advice without a site visit, but we can often help them zero in on the real issue by asking a few questions:
1. How old are the windows?
If they are original to the home then this question is easy to answer, but if they have been installed to replace the original windows, the age may be more difficult to determine. Age is important because it will tell us what type of glass and frame components were likely used. If the frames are metal (typically aluminum) it will be common for there to be moisture on the inside of the frames. This condensation is actually caused by moisture from inside the home, and while it is annoying, it is not an indication of leakage. Most homes in our area built prior to 1990 had this type of window, and they do not meet current building codes because they are so inefficient compared to modern windows. Their metal frames conduct the heat to the outside leaving them cold to the touch. The glass in these older windows is also far less effective at keeping the warm air inside the rooms.
2. Do the windows have water on the inside sill, and is this evident only when it rains or only when it is cold?
If only when it’s cold, then refer to item #1 above. If the answer is when it’s raining, then this would certainly indicate a leak somewhere above the window; but often not the window itself. People call and tell us their window is leaking, but that is because the window is actually a ‘hole through the wall’, so water coming down the wall from above will come into the home at the window. Therefore, to solve the leak it is necessary to know how the water is getting to the window opening in the wall. This may indicate a roof leak, a hole in the siding or stucco, an improper head flashing, or a gap in the exterior caulking. The cause may be the window itself if it is of poor quality or doesn’t close properly due to being out of square.
3. What if the windows are just cold and drafty, but not wet?
High quality modern windows have insulating frames, heat reflective glass units, and are very air tight when closed. Unfortunately, many home builders do not install high quality windows and choose products that merely meet the minimum code requirements because they are less expensive. There is often little that can be done to enhance the performance of low quality windows, but making certain that they are able to close squarely will help. Also, ensure that the weather-stripping is in place and clean of debris. Some rooms may require supplementary heating on the colder days, especially if they are a long way from the furnace.
By far the largest number of cold, wet window issues we hear about are from homeowners with metal frame windows. Some calls are from people with wooden frame windows who have difficulty closing the units tightly due to the swelling of the wood. We also find that wood windows in our wet climate have a real challenge with rot after a couple of decades in the rain. Wood is lovely, and we all like the look of its natural beauty; but it may not be the best choice as a window frame component for Coastal British Columbia. Like the owner of a leaky boat…you can fix the leak or take the boat out of the water…both will solve the problem.