Journal of Korean Institute of Architectural Sustainable Environment and Building SystemsISSN:1976-6483(Print) 2586-0666(Online)한국건축친환경설비학회

Field measurement is necessary for evaluating the insulation performance of existing buildings. As taking the advantage of an infrared imaging system, which is simple and can measure multiple spaces, the wall U-value calculation methods using thermal imaging are suggested in other countries for its accuracy. There are few studies using thermal imaging in Korea and the comparison on exiting methods for calculating the U-value has also barely been attempted. Consequently, no discussion has been made so far to improve the calculation method of U-value using an infrared imaging system. In this respect, this study compares the U-value of walls that are calculated according to the standards and methods for field measurement. For this, the U-value of external walls of an actual building was calculated by applying three methods: (i) heat flow meter, (ii) thermal imaging according to KS F 2829: 2005, and (iii) thermal imaging according to literature. The results showed that the heat flow meter measurement method and the existing thermal imaging method in literature had an error of 8% while that of KS F 2829 was over 100%. The main reason of such a deviation with KS F 2829 is seemingly due to inaccurate calibration coefficients for the field conditions and the surface heat transfer coefficient fixed in the standard.