The potential of conventional heat/energy recovery ventilators have been widely studied, whereas the impacts of defrost cycles are usually neglected. An energy recovery ventilator (ERV) was studied in the Archetype Sustainable House-B (ASH-B) located in Toronto, Ontario. The study provides an experimental evaluation of the efficiency of the ERV unit during normal and defrost operations, as well as its frost resistance to a range of winter temperatures. The parameters that were considered included fan power draw, inlet and outlet air temperatures, humidity, and airflows. Operating the ERV without the defroster revealed a frost resistance of up to -16 degrees C. In addition, the data analysis of defrost cycle revealed two stages of change of fresh air temperature and humidity, which can be used to predict the thermal performance of the ERV unit under different operating conditions. (C) 2014 Elsevier B.V. All rights reserved.