Buildings located in extreme cold climates encounter challenges (e.g., heat loss, condensation, and frozen utilities), especially within their wall envelopes. These challenges also play a pivotal role in occupant health, comfort, and the structural integrity of the building. While the existing literature has primarily focused on thermal performance, this study underscores the importance of evaluating hygrothermal performance within wall envelopes, given the existence of mold growth even in cases of high thermal resistance. Therefore, the aim of this study was to evaluate the hygrothermal performance of an adaptable house wall (AHW) panel that incorporates composite infill panels paired with vacuum-insulated panels to endure harsh cold conditions in Alaska. Therefore, three steps were proposed to: (1) collect the material and thermal properties of the AHW; (2) model the hygrothermal performance of the AHW in WUFI^® PRO v6.7 software; and (3) analyze the results. The results revealed a moderate risk of mold growth in the inner plywood layer of the AHW, whereas the outer plywood layer showed zero risk, indicating an acceptable condition. The findings aid decisionmakers in recognizing potential mold-related issues in building walls before advancing to the construction phase.

Insulating glass units (IGUs) are widely used in buildings due to their enhanced insulation properties and energy efficiency capabilities compared to single-pane windows. Low-emissivity (low-E) coatings are designed as an application on IGUs to reduce the penetration of infrared and UV radiation into the buildings without compromising the daylight exposure. However, these coatings can degrade over time due to environmental exposure, reducing their insulating effectiveness, which leads to increased energy loss and diminished occupant comfort. Therefore, detecting the presence of low-E coatings in IGUs becomes important for evaluating and maintaining their efficiency. To this aim, this study conducts a nondestructive evaluation (NDE) approach, utilizing low-frequency ultrasonics. The objective is to detect the low-E coatings on IGU samples. This research evaluates three IGUs equipped with three different low-E coatings, namely double silver low-E, triple silver low-E, and hard coat low-E, and compares their performance with that of a Clear or non-coated IGU as a reference sample. The main parameter evaluated in this study is the Time of Flight (ToF) to compare it across four samples of IGUs. Findings indicate that the presence of coatings results in reduced ultrasound wave velocity or an increase in ToF. Notably, due to the difference in coatings’ thickness, the hard coating presents longer ToF compared to other coatings. This research holds the potential to support retrofit actions aimed at not only reducing energy losses through IGUs but also enhancing thermal comfort for occupants.