The condensation of water vapour on the internal surface of the walls of a wooden church at Dębno Podhalańskie was studied using a computer program designed by the authors of the paper. Calculations were based on real external and internal thermal-and-humidity conditions. It was found that vapour condensation occurs most often in winter and is usually caused by large groups of people gathering in the church. That phenomenon is much more frequent in the corners of the church where it also lasts longer than in other places on the wall surface. Reducing the relative humidity only by about 5%, while keeping other mocroclimate parameters unchanged, would reduce the time of condensation in the corner by about 40%, and on the remaining surface by about 20%.

101-109