In emergency situations, it is important to provide shelters to protect the population and the support against their environment and to give them some privacy. Unfortunately, tents commonly used in humanitarian context do not ensure comfortable conditions for the occupants. Furthermore, given the very large scale of emergency camps, the intake of fuel in winter condition turns into a major logistical challenge. It is crucial to improve the thermal performance of emergency shelters to (I) increase their indoor comfort and (2) reduce their fuel/wood consumption and related pressure on natural resources. The purpose of this paper is to discuss the difficulties in achieving a realistic thermal model of lightweight structures, taking into account the air permeability of fabrics, their light transmission and the imbrication of several elements (multi-layered shelter). Such a model of the IFRC/ICRC/UNHCR standard family tent is created, based on the building oriented Energy+ thermal simulation model. This model is calibrated and validated by comparing simulation results with in situ measurements realised in the BBRI facility in Belgium, in Burkina Faso and in Luxembourg. This model provides objective assessment of the performance of that shelter for any given context and climate exposure except for night overcooling phenomenon. (C) 2014 Elsevier B.V. All rights reserved.