Area mean temperature for each surface of six walls inside a living room is estimated on measurement using a cubic net radiometer. The walls include a floor with electric heating, a south wall with window curtain, a north wall with curtain in part and a ceiling. Reliability of temperature estimation is discussed comparing measurement of surface temperature of a west wall by 36 sensors of thermo-couple. The result shows high reliability for values of surface temperature obtained by using the cubic net radiometer. In the case of receiving solar radiation on the curtain the error increases between the estimated and the measured.
