Daylighting has always been natural thing for people inside buildings. It serves to create appropriate visual conditions without the financial and energy requirements, but also affects physiology and psychology of human needs and health. Meaningful use of daylighting keeps sustainable development. Currently, there is great emphasis on sufficient insulation of envelopes of buildings with reducing the glass surfaces. Despite the great development in the area of windows, windows are still weakening of the overall building façade. Often designed new windows have minimum dimensions, massive window frames and now triple glazing. These measures may minimize heat losses of the building, but also reduce the amount of daylight in interiors. Such approach has resulted in the lack of light inside the room, which has an adverse impact on human health. This paper shows how some reconstructions can affect daylight inside buildings – e.g. wall thickness, glazing, window frames. Most of reconstructions of building envelopes bring benefits from thermal viewpoint but reduction quality of indoor luminous environment. By contrast, some such reconstructions have beneficial effects both on thermal and optical properties of opaque and transparent elements.