In 2011 the Mackintosh Environmental Architecture Research Unit (MEARU) monitored two demonstration houses each with geometrically identical 2-storey solar buffers. The houses were constructed to the same reasonably high energy-efficiency standards with low air permeability and mechanical ventilation with heat recovery (MVHR) but employing different construction systems – one more heavyweight than the other in terms of indoor thermal response; this situation reversed in the case of respective buffer spaces. To assess the ‘true’ performance of these dwellings sets of students occupied them for separate 2 week periods during February and December 2011, with identical ‘living scripts’ in order to reduce habitation variability. The ‘living scripts’ required heat settings to be consistent, with occupants in February allowed to open windows provided this was recorded. Such interventions between living room and main bedroom and buffer, the latter not linked to the MVHR, were of interest in terms of impact on space heating loads and informed key research questions for buffers in this context. Namely:
a) Would their presence tend to reduce or increase space-heating loads in winter?
b) Would their connection to MVHR be beneficial?
c) How would their performance compare with direct-gain windows to Passivhaus standard?
Keywords: Scotland, winter, sunspace, buffer, ventilation.