Wooden houses made of logs have been built in Rus’ for centuries. Beginning from the seventeenth century, wooden cladding began to be installed on the outside of log walls, creating an air gap between the boards and logs of the frame, which was ventilated through the gaps between the siding boards. Such structures became the prototypes of modern ventilated facade systems, in which wooden siding protected the logs from the negative effects of the atmosphere and contributed to the increased durability of the log house. The development of stone house building pushed the research of wooden structures into the background, however, at present, due to the revival of wooden house construction, the study of the properties of wooden structures has been resumed, but very little research has been devoted to thermal engineering studies of wooden house elements. In this regard, the article presents a study of the thermal insulation qualities of wooden log houses with wooden siding and air gap. The work shows that the board siding allows the increase of the temperature on the inner surface of the log house, including in the groove area, by 3.5–4.5 °C. This eliminates the formation of condensation on the inner surface of the wooden structure in winter and ensures high durability of wooden walls. Also, siding protects the log house from negative wind impacts, and helps to reduce the infiltration impact on the structure by 1.5 times.