A New Method of Pixel-level In-situ U-value Measurement for Building
  Envelopes Based on Infrared Thermography
Zihao Wang Yu Hou Lucio Soibelman
The potential energy loss of aging buildings traps building owners in a cycle
of underfunding operations and overpaying maintenance costs. Energy auditors
intending to generate an energy model of a target building for performance
assessment may struggle to obtain accurate results as the spatial distribution
of temperatures is not considered when calculating the U-value of the building
envelope. This paper proposes a pixel-level method based on infrared
thermography (IRT) that considers two-dimensional (2D) spatial temperature
distributions of the outdoor and indoor surfaces of the target wall to generate
a 2D U-value map of the wall. The result supports that the proposed method can
better reflect the actual thermal insulation performance of the target wall
compared to the current IRT-based methods that use a single-point room
temperature as input.