This study aims to evaluate thermal performance using the ASTR method. Its findings are as follows: 1) The measured U-Values of 49A type and 59A type walls were almost the same as the theoretically calculated values. 2) One notable phenomenon for both walls was that the interior surface temperatures of the channels attached to corners were up to 10.4% lower than that of the cross of the wall, even though they consisted of the same materials. This is due to the surface temperature drop caused by the thermal bridge. 3) The surface temperatures of the thermal bridge were converted into U-Values. The U-Value of the top left corner on the 59A type house was 1.044W/m²K, and of the bottom right corner on the 49A type house was 0.959W/m²K. Therefore, the thermal performance of the thermal bridge area was decreased after construction. 4) Differences were found in the results of comparing heat transfer analysis simulation data and measured data. A maximum difference of 12.4% occurred in the top left corner on 59A type, and of 7.6% occurred in the bottom right corner on 49A type. 5) The results of a heat transfer analysis simulation showed that the temperature of both 49A type and 59A type top right corner were the lowest, but in-situ measurement results were the lowest in the bottom right corner on 49A type and in the top left corner on 59A type. These results are considered to be due to the occurrence of thermal bridges and a deterioration in the construction quality.