Infiltration and ventilation measurements on three electrically heated multifamily buildings.

In recent years, increasing importance has been placed on energy efficiency in residentialbuildings. This has resulted in tighter buildings, which raises concerns about the amount ofventilation required to provide acceptable indoor air quality. Relatively few studies have beenconducted on multifamily buildings, where the multiple zone interaction makes testing andanalysis difficult. In order to address this problem, detailed testing of air flows, pressures, andtemperatures was done at three electrically-heated multifamily buildings in the U.S. PacificNorthwest under heating season conditions. These were done in-situ using multizone tracergas technology. Tests were short-term tests, with several fan tests perfomed each day for atest period of about a week. The average natural infiltration for each of the three buildingsranged from 0.14-0.22 air changes per hour (ACH), with individual units ranging from 0.075-0.31 ACH. Due to stack effect, units on lower floors experienced a higher percentage ofoutdoor air in the total unit flow. Interzone flows were found to be dominated by stackeffects. With ventilation fans in all of the units on, the average outdoor air ventilation for thebuildings increased to 0.38-0.47 ACH with individual units ranging from 0.31-0.54 ACH.