A review of the use of infrared thermography in building envelope thermal property characterization studies

International standards used to carry out building envelope energy audits such as ISO 9869 rely on using heat flux meters (HFM) and temperature sensors on indoor and outdoor walls in-situ as inputs in calculations to determine thermal properties. Obtaining these measurements may be restrictive, expensive, and time-consuming. By contrast, obtaining temperature measurements using infrared thermography (IRT) is accessible, inexpensive, and quick. For these reasons, an auditing methodology which could solely use IRT to perform most building audits would be beneficial on many fronts. However, this practice is unfavored as it is viewed as being unprecise and involves considering numerous environmental factors which may be inaccurate and difficult to model. The present review article serves as a critical analysis of measurement techniques and models currently used in energy auditing research, detailing their advantages, drawbacks, and accuracy, and examines how, with improvements in methodology and with proper environmental modeling, IRT imagery could be used in place of HFM in building envelope auditing standards such as ISO 9869, potentially saving time, effort, and costs in related research and commercial activities.