This article aims to present the coupling of a direct thermal calculation with an optimization algorithm to identify the thermal characteristics of a simplified building wall. The resolution of the direct thermal calculation is first based on an electric network representation that is numerically solved with a finite difference method. The optimization model minimizes a criterion, such as least squares, between the expected temperatures inside the building and the model response using a reflective Newton inverse iterative algorithm. The proposed optimization method is validated using an experimental study of a cubic wooden structure under controlled ambient conditions and a uniform heat source.