From a wide range of bibliography (148 publications composed by books, guidelines, scientific papers, and other documents), the study presents a critical review of the use of the infrared thermography (IRT) survey in the building energy audit. After explaining its historical growth, the applicability of passive and active approaches has been described, considering well-established and emerging techniques, general procedures, types of IR-camera used, technical issues, and limitations. The passive approach is the most common to detect thermally significant defects. Thus, a specific procedure for the energy audit has been reported, matching different standards, guidelines, and professional advice. Similarly, recurring energy related problems are toughly presented (i.e. thermal characterization of buildings; thermal bridging, insulation level, air leakage and moisture detection; indoor temperature and U-value measurements; human comfort assessment). Finally, advantages and potential sources of errors as well as future trends in the use of IRT for the energy audit have been described. The research aims to serve as a reference for energy auditors and thermographers, to decide upon the best procedure for detecting specific energy defects.