Using the building energy simulation software TRNSYS, this report investigate the heating potential and cooling potential of an ETAHE in a mechanically ventilated passive house, ranging in size from a detached house to a small office.  Simulations of the ventilation system within a small office indicate that a parallel piped ETAHE, connected to an efficient air handling unit, will provide energy savings ranging between 6 and 14.6 kWh/m² floor space during a normal year with base ventilation at night and 4 air circulations per hour during day.