Abstract
Newly constructed multi-residential buildings with more than 500 households should be flushed out indoor contaminants using a mechanical ventilation system or large fans after the completion of construction and prior to occupancy by the Heath-friendly Housing Construction Standards since 2014. In addition, the standard recommends to maintain indoor temperature over $16^{\circ}C$ and relative humidity below 60% while performing the flush-out. However, it is difficult to maintain these recommended indoor conditions, especially during winter season because additional energy cost is needed for space heating. Therefore, in this study, additional energy cost including heating and ventilation energy cost in multi-residential household for flush-out during winter season was estimated using building energy simulation program called EnergyPlus. Additional energy cost according to various conditions for performing flush-out (such as performance period, ventilation rate, and heating set-point temperature) was analyzed. Based on the results of the energy simulation, the energy cost was estimated to be ranged from 14,625 to 29,452\/household in Incheon city and from 3,521 to 26,268\/household in Gwangju City. There was no significant change in energy cost according to the performing terms of flush-out between Incheon and Gwangju City.