This document summarizes a study that uses computational fluid dynamics (CFD) to compare the transient conditions of an Earth Air Tunnel Heat Exchanger (EATHE) system operated continuously versus intermittently in winter. Simulations were conducted for a 60m long pipe buried at 3.7m depth using three soil thermal conductivities. Results show intermittent operation provides a greater rise in air temperature compared to continuous operation, with more significant improvements seen for soil with lower thermal conductivity.