What is Condensation Resistance and when is it important? Condensation forms on a window when the pane temperature is lower than the dew point of the air outside, more often when indoors has a higher humidity. Condensation is not always a problem to consider though. This is true for those who live in arid places such as Arizona, but for most other states, this is something to consider when looking at replacement windows.
CR and CRF
There are two measurements that computes a relative humidity resistance. They are not related as they are two different measurements by two different organizations.
Condensation Resistance (CR) is by the National Fenestration Rating Council (NFRC). This rating is on a scale range from 1 to 100. The higher the number the more resistant to condensation. It specifically measures the performance of parts of the window assembly through different temperatures and humidity levels. Condensation Resistance Factor (CRF) is by the American Architectural Manufacturers Association (AAMA), now the Fenestration & Glazing Industry Alliance (FIGA). This rating is on a scale of 30 to 80. Higher the number the better that resistance. Before merging into their new organization, they had a calculator, which is now longer available. This test is based on frame temperatures combined with weighting factors. The problem is is that this test has limited climate conditions to determine the resistance that may not be applicable depending on where you live.
Although these measurements seem to be an important and effective way to determine which windows to get, they are not based on field performance observations. This means they don’t take into account the other factors that can affect condensation resistance in your home. So remember, they don’t hold much weight in the industry. Therefore, they usually aren’t included on the energy performance label.
There are other things that can affect if a window will have condensation or not. This includes moisture in the home, house plants, certain hobbies, ventilation, window treatments, etc. Also, if you see condensation, pay attention to where it’s located. If it’s on the outside then this is due to condensation. If it’s between the panes, this can be a seal failure. A contractor should inspect any possible seal failure.
Window treatments can reduce the airflow across the window. This means the window will cool and condensation can form.
Another consideration is where within the frame the window is installed. The further towards the outside wall, the less interior airflow and the colder the frame will be, the more likely it’ll be for condensation to form.
Although there is not a one size fits all measurement to determine which window to go with, for the most part, modern windows should have reduced chance of condensation. Either over time, or if your window isn’t appropriate for where you live, problems can arise.
Moisture accumulation can lead to frame, drywall, and structural damage. As well, there is a possibility that if enough moisture leaks into your walls, that mold can grow. There are several things you can do to reduce the possibility of these things happening.
One simple solution is to reduce the humidity inside your home during the colder months. Another solution is to make sure that the flashing is done correctly. Also, make sure the interior and exterior of your windows are sealed properly. As well, proper ventilation throughout the home is important. Make sure your bathroom, laundry room, and kitchen have proper exhaust systems.
Besides the environmental factors in and outside of your home, the actual construction of your replacement window should be considered. Nowadays are constructed with materials that are less conductive, and therefore less apt to produce condensation. More often than not, replacement windows are double or even triple pane. In Between these panes is not air, but gases that reduce transfer of temperature between the indoor and outdoor. As well, the spacers used between the panes of glass are no longer aluminum, which is highly conductive, but rather stainless steel, tin steel, and foam polymers.
Overall, the construction of windows today have greatly improved. They are made with energy efficiency in mind. As a result, without necessarily focusing on it, windows already reduce the likelihood of condensation.
Condensation Resistance, when is it important? Overall, CR and CRF are not the most important rating you should consider when choosing a window. There are other ratings that are much more respected by the energy star rating. Remember, how your replacement windows are installed in the frame, and properly sealing affect condensation resistance as well. As well, remember that condensation may be inevitable or never an issue depending on where you live. If you do live somewhere that gets very cold in the winter, condensation will probably happen at one point or another. You can help reduce this chance further by maintaining certain humidity levels in your home.
So when looking at replacement windows take into account other ratings before CR/CRF. As long as you are having quality replacement windows installed in your home, you are already on your way to having less condensation. Just keep in mind your habits and hobbies inside your home, and adjust the indoor environment accordingly.
Shakespeare Home Improvement Co. is the exclusive dealer of Great Lakes Windows here in Lancaster, PA. They are a highly respected window manufacturer with a commitment to high quality, energy efficient windows. Contact us today for your free estimate on your replacement windows.