Wide-ranging use of glass systems in modern sacral architecture extends the traditional dialogue between indoor and outdoor space and makes architects look for new forms or harmony between the two, at the same time keeping focus on the most important thing – sense of God’s presence and idea of spiritual transcendence. Compositional application of coloristics, light and shadow under the impact of insolation and visual accents created by the play of light and shadow should underline altarpiece in church space creating the necessary balance and arranging priorities in the right order. Aesthetic harmony has a subordinated significance. A picturesque landscape seen through a glass system has only a subordinate importance. Harmony of indoor/outdoor space in sacral architecture is achieved only in those cases when expressing a hierarchy or priority values such as an altarpiece accentuated with the help of light, interior design opening to the sky, picturesque view of nature. In order to reach the maximum result a synthesis of mentioned methods is recommended.