However, there is more going on here than simple lack of information. First, occupants are made aware of the ERV system from building management in the form of a twice yearly email about owner-performed ERV filter maintenance. They are also confronted with the control surface every time they walk into the bathroom. It is interesting to point out that there was no difference in the usage rate between renters and owners in the study buildings, both had similar use patterns of their ERV system; suggesting that the building handover and education procedure which owners underwent when acquiring their dwellings did not produce a higher rate of usage. This indicates that occupant training is not a silver bullet solution for increasing usage of this important appliance, and the energy efficiency of these dwellings.
Negative comments about the ERV system in Table VI provide substantial guidance in understanding underuse of ERV systems. One trend in the comments echoes Carmona-Andreu et al. (2013, p. 5), who found that “there was no demonstration of how to get into [ERV] unit for cleaning the heat exchanger filter”. Comments 3-7 (Table VI) clearly show that occupants are either unaware or unduly challenged by the task of cleaning the ERV filter, which could lead to outright abandonment of its operation (i.e. comment 5).
As mentioned earlier, the noise created by the ERV systems represents another barrier to their use. Respondents’ comments clearly show dissatisfaction with the noise level during operation, which is likely a factor in ERV underuse. Thus, the logical explanations for ERV underuse, though varied, seem to centre around perceived ineffectiveness (frustration), lack of knowledge (confusion) and the noise caused by the fans themselves (inconvenience). It is important to understand this phenomenon, as it helps to begin to answer the complex questions: how much control should be given to occupants of residential green buildings? and How much complexity and responsibility can they effectively manage? Clearly the provision of in-dwelling ventilation warrants continued attention by designers and managers.