This dataset provides high-resolution experimental data for the thermal performance of an active triple glazing unit equipped with a transparent heating foil. The data was collected to validate numerical CFD models and analyze heat transfer reduction in extreme winter conditions (down to -25°C). The study investigates the transition from passive insulation to active thermal barriers. It demonstrates how active compensation can stabilize internal glass surface temperatures above 18°C and eliminate condensation risks. The dataset includes spatial thermal mapping, heat flux measurements, baseline reference data for passive windows, and high-resolution raw sensor logs (1-minute intervals). This dataset is licensed under a Creative Commons Attribution 4.0 International license (CC-BY 4.0). Users are free to share and adapt the data, provided that appropriate credit is given to the author, the Kielce University of Technology. This research was funded in whole or in part by the National Science Centre, Poland,DEC-2025/09/X/ST8/00339, "Integrating photovoltaics with electrically heated windows: a pilot investigation for enhanced building energy efficiency."For inquiries regarding the dataset, please contact: hkoshlak@tu.kielce.pl