Scottish Passive House: Insights into Environmental Conditions in Monitored Passive Houses

Abstract

Climate change and sustainability legislation in recent years has led to significant changes in construction approaches in the UK housing sector. This has resulted in the adoption of new building typologies, including the German Passivhaus (Passive House) standard. This standard aims to improve occupant comfort and energy efficiency, potentially changing the ways in which homes operate and how occupants interact with them. With increasing construction of low energy dwellings, there is an emerging gap in knowledge in relation to occupant health and wellbeing, thermal comfort, and indoor air quality (IAQ). Using data collected from a two year Building Performance Evaluation (BPE) study funded by Innovate UK, the environmental data (temperature, relative humidity and carbon dioxide concentrations) from five Certified Passive House homes in Scotland was compared. The results demonstrate problems with overheating with peak temperatures exceeding 30˝C. Imbalanced mechanical ventilation with heat recovery (MVHR) systems were identified in 80% of the dwellings and inadequate IAQ was found due to poor ventilation. Only one of the Passive Houses studied exhibited thermal conditions and IAQ which were, on the whole within Passive House parameters. This paper outlines the insights and the main issues of Scottish Passive House in the broader context of sustainability.

Stressing the passive behavior of a Passivhaus: An evidence-based scenario analysis for a Mediterranean case study

“…Similar issues have been reported also for the colder climates of Scotland [28] and Estonia [29], as well as for the continental one of Slovenia [30] and Romania [31].…”

Passive House and Low Energy Buildings: Barriers and Opportunities for Future Development within UK Practice

“…Surveys of a modest sample of Passive House buildings were carried out in-situ [49] and supported the conclusion of research identified earlier that the Passive House standard was robust and gave predictable savings. Research has also shown however that some Passive House dwellings have exhibited some more marginal outcomes [50] and that there is some lack of information in published sources about performance. The study examined five dwellings in Scotland and indicated concerns in the areas of indoor air quality, comfort and occupant health.…”

Indoor Air Quality in Passivhaus Dwellings: A Literature Review

“…The identified literature includes four studies that reported from virtual simulations [ 47 , 51 , 52 , 66 ], one study based on occupant perception of IAQ, three used low-cost monitors [ 41 , 44 , 56 ], twenty-nine included physical IAQ measurements [ 41 , 42 , 43 , 44 , 45 , 48 , 50 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 63 , 64 , 65 , 66 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 ] and fourteen studies assessed IAQ through both physical measurements and occupant perceptions [ 41 , 42 , 43 , 55 , 56 , 58 , 59 , 64 , 65 , 66 , 72 , 73 , 76 ]. Only thirteen of these measured IAQ metrics other than CO 2 [ 41 ,…”

“…One of the biggest challenges to compare IAQ between different studies is the lack of homogeneous methods to report IAQ. Some studies do not describe the energy performance (four studies: [55,56,72,77]) or describe IAQ absolute values (fifteen studies: [43,44,46,50,51,57,58,61,[65][66][67][68][69][70]75]) and express relative levels (i.e., percentage of time above or below particular thresholds)-which also happen to vary from one study to another, in addition to the differences of monitored periods. Additionally, the timeframe on which studies are conducted varies.…”

“…Some studies suggest that they may actually exacerbate, rather than resolve, IAQ problems [101]. A significant concern of sizing residential MVHR units has been noted in current Passivhaus practices, as they deliver the same background ventilation regardless of occupancy levels [50]. It is clear that in order to benefit from the above, MVHR systems should be adequately designed, commissioned, installed, maintained and operated.…”