Earth to Air Heat Exchangers (EAHEs) are reliable complements for conventional HVAC systems. During summer, EAHE cooling can help reduce energy consumption. In the present study, to evaluate the cooling performance of a two-layer EAHE ventilating system, experimental work was conducted from May to August 2017. Because EAHE performance largely depends on the thermal characteristics of soil, an irrigation system was adopted to experimentally verify the effect of soil moisture content. Air temperature showed an average drop of 14.6 degrees C and the average total cooling capacity was 8792W. The system exhibited a maximum coefficient of performance (COP) of 27.2, implying that the system provides fresh-air cooling with little electricity input. Under cooling mode, the surrounding soil temperature increased continuously due to the operation of the system. An irrigation system was adopted to simulate natural precipitation; when the soil moisture changed from 0.37 cm(3)/cm(3) to 0.42 cm(3)/cm(3), air temperature decreased by 1.6 degrees C at the pipe outlet. The results show that using EAHE under wet conditions resulted in a large cooling capacity and COP, which indicates that a short pipe length or shallow depth is required for achieving a similar cooling capacity under wet soil conditions. (C) 2019 Elsevier B.V. All rights reserved.