Evaluating the influence of building fabric, services and occupant related factors on the actual performance of low energy social housing dwellings in UK

Abstract

This paper empirically investigates the influence of building fabric, services and occupant related factors on actual energy use of six case study dwellings, located in three new low energy social housing developments in UK, covering a variety of built forms and construction systems (timber frame, hempcrete, steel-frame). Physical monitoring of indoor environment and window-opening is cross-related with building fabric and systems' performance, and qualitative data gathered through occupant surveys, review of control interfaces and handover guidance, to understand the causes of the gap between modelled and measured energy use. Actual energy use is found to exceed design expectations by a factor of three, questioning the need for whole-house mechanical ventilation heat recovery (MVHR) systems at measured air permeability rates of 6m³/(h.m²) against the design target of 3m³/(h.m²). Lack of proper commissioning of MVHR and heating systems, combined with inadequate user comprehension about their operation and control leads to occupant 'misuse' wherein systems are de-activated, thereby negatively affecting indoor air quality. This is confounded by occupant factors related to higher demand temperatures, unexpected opening of windows during winters due to under-performance of MVHR combined with habitual behaviours, and over-use of heating systems to compensate for higher than expected air permeability.

Developing a new framework to bring consistency and flexibility in evaluating actual building performance

“…Project 3: BPE study of low energy homes in Swindon, UK (Gupta et al, 2018) The study evaluated two low energy (CSH level 5) homes within a new low energy housing development in Swindon. The project ran for three years starting from the pre-handover stage and was funded by a UK Government programme.…”

Going smart, staying confused: Perceptions and use of smart thermostats in British homes

“…Despite these systems being suggested to generate energy savings and better heat distribution [59], [60], there is sparse research on user perceptions of underfloor heating systems and, in particular, whether slow response times pose a challenge. Recently, [61] found that underfloor heating systems were about as unfamiliar to users as heat pumps, with a lack of understanding of how they operate causing controllability issues. Two more studies found conflicting comments on the comfort provided by underfloor heating; in one, some respondents complained of excessive heat generated by the system [62] and in the other of insufficient heat [63].…”

The Role of Occupants in Buildings’ Energy Performance Gap: Myth or Reality?

“…The characteristics reported are generally inconsistent across the studies due to differences in research foci and data availability issues. The most reported characteristics are the number of people [9,10,15,26,33,49,59,60,[79][80][81], age [9,10,15,17,21,26,33,59,77,80,81], household composition [6,7,12,14,17,30,59,77,80,82,83], and income [9,10,21,26,29,33,79,80]. Additional characteristics reported were ownership status [9,10,26,79,80,84] and education levels [17,21,…”