Quantification of heat energy losses through the building envelope: A state-of-the-art analysis with critical and comprehensive review on infrared thermography

This study starts from the common approaches for the U-value evaluation (analogies with coeval buildings, the calculation method, the in-situ measurements and the laboratory tests), with the underlying standard procedures and the most important advantages, problems, and potential sources of errors defined by the literature. Then, the IRT technique, and its development through the years, is detailed and discussed, focusing on analogies and differences among the available literature sources. Also, several recurring energy related problems, such as the detection and estimation of thermal bridging as well as the assessment of the ε-value of building materials, are shown. Finally, the qualification of IRT personnel and the perspectives in the building sector are briefly explained, to remark the need for specialized thermographers who deal with an evolving methodology.