摘要:“Ecological buildings” and “energy-efficient buildings” are concepts which we encounter on a daily basis and which define modern trends. The purpose of their design is to create an optimal thermal microclimate by means of heat flows that form within it or enter it. A balanced combination of heat flows creates suitable conditions for thermal comfort—a factor contributing to the quality of the internal environment of buildings. This research addresses the problem of heat distribution in construction materials based on wood and their thermal–technical properties in relation to the sustainability requirements for the thermal–technical properties of constructions and buildings. The research examines the structural parts of the external walls of modern log constructions. The objective of this work is to analyse the thermal–technical properties of the structural parts of modern log wood constructions in laboratory conditions and verify them against calculated values and values declared by manufacturers. This publication is also a contribution to the current needs in terms of the sustainability and internal environment quality of constructions in general. The publication is also a contribution to the current needs in the field of heating technology in terms of sustainability and the quality of internal environments.