Thermal properties of door and window access systems

Over the past decades, building skins have become much better insulated to minimize the operational energy requirements of buildings. One of the foci for increased insulation properties of building skins are doors and windows, as they have traditionally suffered from insufficient thermal properties. Today, systems exist that provide outstanding insulation properties, with the look being the weak spot. Water inside the access systems influences sensitive electronics controlling and operating the look and damages wood-based doors. Thus, research was conducted to evaluate existing looks’ performance regarding thermal insulation, air tightness, water tightness, and condensation. Based on these tests, prototypes of improved locks were then constructed and tested.
Researchers at Bern University of Applied Sciences investigated a door look system to address the shortcomings of existing looks in respect to thermal insulation and condensation. For the purpose of this research, a door look system comprises of door handle, lock cover, and the closing and locking mechanism. Such an access system that is available on the market was tested in respect to thermal insulation, air tightness, water tightness, and condensation on an actual building built according to the Minergie standard.
Results show that temperatures throughout the access system tested follow the respective temperatures on both sides of the system, indicating the existence of less than optimal thermal properties under the viewpoint of hands-friendly surface temperatures. Humidity inside the access system is also dependent on the outside conditions on both sides of the system. However, humidity inside the system is also dependent on the pressure differential between the two sides. While no damaging levels of humidity inside the access system were measured at any time during these tests, results indicate a need to design a better access system case to increase its surface temperatures and to reduce the existence of humidity inside the access system to better protect the electronic components of the system as well as the door itself.