Global warming is caused by greenhouse gas (GHG) emissions produced from the use of fossil fuel-based energy sources. Buildings consume about 30% to 35% of the global energy use, which makes buildings a major contributor to the global warming problem. A long-term plan has been established at the Thermal Processing Laboratory (TPL) at McMaster University to investigate the use of various renewable energy-based technologies to achieve net-zero energy buildings (NZEB) in Canada. This paper presents results of an investigation of the effectiveness of using a thermal buffer zone (TBZ) in real-size buildings. A TBZ is a closed passage built around the building that allows air to passively redistribute heat energy from solar radiation received on the south side throughout the building. A TBZ offers an effective solution of the overheating problem usually experienced on the south side of the building, and at the same time, it helps in reducing the heating load of the north side of the building. An experimental setup employing TBZ in a lab-scale model of a typical building floor has been built. An analytical model of the TBZ has been developed. The experimental data has been used to validate the developed analytical model, which then was used to predict the performance of the TBZ implemented in a real-size building floor, considering four cases. Results of the first three case studies considering the use of TBZ in cold and hot climates, with and without thermal insulation, show that the predicted effectiveness of TBZ could reach 117% and 72.5% in the winter and summer, respectively. Results of the fourth case study considering the effect of integrating a fan with the TBZ show that a fan is beneficial up to a certain fan power, beyond which the use of the fan would not be feasible. Results presented herein confirm that the TBZ is an effective means of integrating solar energy into buildings, thereby reducing buildings' fossil fuel-based energy consumption.