Structural and material solutions of modern buildings are an important element of considerations in accordance with the idea of sustainable design, in which the aim is to minimize their negative impact on the environment. These searches turn towards low-tech technology, which uses natural and low-processed materials, which are possible to obtain in selected locations. Construction in the raw earth technology is a modernization of the traditional technology, in which it is possible to apply pro-ecological values associated with the used material. The paper presents research on insulation properties of walls in an experimental earth building located in Pasłęk in Poland. The aim of the research was to determine the potential of the applied raw earth technology in a local climate. The accepted design assumptions were verified due to the effects achieved in the empirical research on the thermo-humidity conditions in an experimental building. On the basis of the conducted research with the use of specialized tools, the positive and negative sides of the selected technology and building material were determined.