The POE approach was particularly useful here because the underuse of ventilation arises from issues which could only be uncovered by asking people about how they actually perceive and interact with their device. That is, complaints centering around noise, perceived ineffectiveness, lack of awareness and confusion are best understood in practice, as opposed to in a laboratory or modeling program. Comments clearly show that respondents are disappointed and/or frustrated with their ERV system. This “perceived ineffectiveness” taps into an important idea in the usability/control literature. Baird (2010, p. 21) writes that “the occupant also appreciated being able to see or feel the effect of their operating of any of the control systems to which they had access”. That is, respondents were likely not seeing the results they had expected from their ERV systems (e.g. quick steam removal after showers), and stopped using them.
Respondents’ dissatisfaction with their novel ventilation system is very likely, resulting in higher than predicted heating energy consumption. The ventilation systems in the respondents’ dwellings recover approximately 74 per cent of the heat from exhaust air when operated in low speed mode with an incoming air temperature of 0 Celsius (Venmar, 2013). Bypassing this system is obviously going to result in increased energy use by the fan coil system, which now must deliver heated air to the dwelling without having it preheated by the ERV beforehand. This suggests that performance gaps can be intricately linked to occupant satisfaction and behaviour within buildings. As Janda (2011, p. 17) said: “buildings don’t use energy, people do”.