In situ measurement of thermal transmittance and thermal resistance of hollow reinforced precast concrete walls

•Thermal performance of precast concrete walls was evaluated by in situ measurement.•Thermal transmittance depends on wall orientation and outside weather conditions.•Thermal resistance is independent of the wall orientation.•In situ mean thermal transmittance lies in the range of 1.459–1.803 W/m2 K.•Six days is sufficient to ascertain the in situ thermal performance parameters.

A study was conducted to determine the in situ thermal transmittance and thermal resistance of two exterior reinforced precast concrete walls of a building constructed with hollow panels. The results indicate that the North and East facing walls have a mean thermal transmittance (air to air) of 1.459 and 1.803 W/m2 K, respectively. The mean thermal resistance value (surface to surface) of the North and East walls is 0.355 and 0.352 m2 K/W, respectively. While the thermal transmittance depends on the wall orientation and the outside weather conditions, the thermal resistance is independent of the wall orientation. The results also indicate that a monitoring period of six days is sufficient to ascertain the in situ thermal transmittance and thermal resistance of reinforced precast concrete walls.