Increased indoor air humidity in cultural heritage buildings in the Baltic States region results in the deterioration of cultural heritage values. Existing norms, standards, and research do not specify the necessary conservational microclimate indoor air parameter limits. Two main types of historical cultural heritage building constructions exist based on enclosing structures – wood and masonry, with various heating strategies and usage intensities. This study complements previous research on the microclimate of Krimulda Church and compiles measurements of three additional Latvian churches: Turaida Church, Riga Jesus Church, and Liepaja St. Trinity Cathedral. Microclimate measurements were conducted in two wood and two masonry churches. Humidity ratio and moisture excess calculations were derived from the measurement data. Results indicate that in certain cases, the moisture excess threshold of 6 g/m3 and indoor air humidity ratio threshold of 15,6 g/kg are exceeded, posing a significant risk of condensation. Moisture evaporation levels from masonry church constructions were identified. The study reveals conservational microclimate indoor air parameter limits for various types of churches in the Baltic States climatic region.