Abstract
This study presents findings based on the analysis of a four-year dataset (2021–2024) of surface temperature measurements from a highly insulated Zero Emission Building in Trondheim, Norway. 20 sensors were installed at the wind barrier of the four lateral façades and at the roofing underlay within ventilated cavities. Measurements were collected at 15-minute intervals, averaged to hourly values, and aggregated by envelope orientation. The analysis includes statistical summaries, temperature distributions, and seasonal and diurnal patterns, revealing distinct microclimatic differences between orientations. The roof exhibited the highest recorded temperature (53°C) and the south façade the widest total range (71.1°C), while the north façade consistently showed the smallest deviation from ambient air conditions. Seasonal patterns aligned with solar exposure, with peak temperatures occurring in the morning for the east façade, midday for the south façade and roof, and late afternoon for the west façade. The dataset was further used to estimate relative thermal ageing rates using the Arrhenius equation for the two most commonly used polymers in a building envelope which are polyethylene (PE) and polypropylene (PP). Depending on the phase of degradation, thermal ageing is on average between 11 % (PP, west façade) and 71 % (PE, south façade) faster compared to the north façade. By providing long-term, orientation-specific microclimatic data, this work offers a valuable basis for developing representative laboratory ageing protocols and for improving service life predictions of polymeric building products under realistic operating conditions.