Experiences with sound insulating open windows in traffic noise exposed housing

Sound insulating windows are widely used in traffic noise exposed residential areas to reduce indoor noise levels to acceptable levels. However, such windows are typically only designed to provide sound insulation in closed position, and many people prefer open windows parts of time for ventilation purposes, including during night, or simply because it’s a good feeling to have windows open to be in contact with the surroundings. High noise exposure can lead to adverse effects on comfort and health, and thus, there is a need for sound insulating open windows to reduce noise exposure in homes, when windows are open, not least to reduce sleep disturbance. Unfortunately, such window solutions are complicated and expensive and practical experience limited. Nevertheless, they have been included in some Danish projects. To support further development and use, experience from seven field cases with different solutions has been collected, and additional field experiments have been carried out in a case with transparent external shutters with sound absorbing slits for ventilation along window sides.
It is concluded that occupants in general are satisfied with the solutions and further development for more general use is recommendable, but investigation of ventilation performance should be integrated in future research.