Abstract Ventilated wall is considered as an effective technique for building energy efficiency retrofit in hot-humid areas, and the heat exchange inside the ventilated layer blocks the heat gain into the wall. Most current researches focus on the performance assessment of the wall system but lack the optimize design of the external board. Here we demonstrated a new type of ventilated wall, using the calcium silicate material as the cladding panel for its excellent physical properties and easy installation and maintenance. In particular, the aluminum foil was attached to the interior side of the board to further lower the emissivity for achieving a better insulation effect. Based on the field experiment in summer days, the thermal performance of the new type of ventilation wall was obtained and further compared with the conventional wall. Moreover, the equivalent thermal resistance of this novel ventilated wall was also calculated. The results revealed that: the interior wall surface temperature and energy consumption of the new ventilated wall proposed was about 3-5°C and 39.2% lower than those of the conventional wall, respectively. The low emissivity significantly insulated the heat transfer inside the cavity. In parallel, the calculated equivalent thermal resistance of the ventilation wall (0.971m2⋅K/W) was also 2.07 higher than that of the conventional wall.