The basic benefit of low-temperature radiant heating systems is thermal comfort. Additional sound insulation and high inertia factor that provide heating of the surfaces, even without initial phase of energy consumption, can be regarded as an advantage. This paper discusses benefits of low temperature systems installed under the floor or wall surfaces. This study is aimed to demonstrate the influence of heating system elements on indoor air parameters especially on internal surface of building envelope. The model described in this paper offers to optimize building energy performance with low temperature pipes built in the construction.