Abstract This paper presents an experimental study of a new designed Trombe wall, which is a part of the southern wall of a test room, in terms of energy performance and heating comfort during winter operation for Yazd city (Iran) desert climate. The area of the Trombe wall is 50% of that of the southern wall of the test room. Hence, it occupies less space and reduces the implementation costs. Contrary to the traditional Trombe walls in which the absorber receives solar radiation from one direction, this innovative design enables the absorber to receive solar radiation from three directions (East, South and West), therefore, the absorbing surface of the wall is subject to the solar irradiation during the all day time (from sunrise to sunset). The experimental results revealed that the range of room temperature on the coldest winter days and weeks in Yazd is kept within 15–30 °C, and this implies that the present Trombe wall design is able to provide a comfortable indoor temperature with lower difference between the maximum and minimum temperatures due to the increased stored energy of the Trombe wall. Furthermore, the present innovative design of the Trombe wall channel causes the absorber temperature to reach around 47 °C on the coldest winter days, indicating the highest possible solar intensity received by the absorber. Analysis of the hourly stored energy of the Trombe wall reveals that the more solar intensity leads to the more energy absorption and the higher Trombe wall back surface temperature, which in turn causes the hourly stored energy to reach to a maximum of 5800 kJ/h in February.