Climate change impacts the thermal performance of buildings, accentuating the need for adaptive architectural systems. This study optimizes thermal comfort in dwellings in cold-dry climates through passive heating that takes advantage of solar irradiation. Two 1:5 scale prototypes were built in Juliaca, Peru: one with Agrofilm (APHS) and one with recycled PET (PPHS), plus a control group (CG). During the four winter months, the APHS, at $21.33, achieved daytime temperatures of 26.6 °C, higher than the CG (20.4 °C), making it viable for communities with limited resources. The PPHS, at $37.33, maintained nighttime temperatures of 14.99 °C, excelling in heat retention. Both systems faced challenges in moisture management, affecting thermal inertia and pointing to the need for improved PET shingles on the PPHS to reduce thermal bridging. Although APHS is more economical and efficient during the day, PPHS offers durability and lower maintenance, making it suitable for long-term sustainable applications. This study suggests optimizing materials for high cloud cover environments and further researching passive heating systems for similar climates, contributing to sustainability in high Andean areas.