*5.3.3. Discussion*

A contributory factor to the poor performance is the layout of the system, with the two air delivery registers focussed into the hall space only.The intention behind this design was that air would migrate from this central location into adjacent apartments. However, fire regula‐ tion requirements for self-closing fire doors and smoke seals prevent such air movement. The situation appears to have been exacerbated post-construction, as carpet installation has further reduced the air spaces under doors.

With the potential health impacts, the importance of good IAQ cannot be a secondary con‐ cern and it must not be undermined by attempts to improve thermal efficiency and air tight‐ ness. Not withstanding this position, the level at which poor air quality is perceptible has the potential to cause occupants to manually seek improved ventilation. With a CO2concen‐ tration of 1000ppm poor air quality is perceptible to humans with the stress initiated behav‐ ioural response invariably being one of window opening and the result being, as was evidenced with the poor thermal control, one of high energy loss. Instances of this were identified through in the monitoring of this project and the outcome of poor air quality is (entirely rational) behaviour that counteracts the approach to energy conservation central to a contemporary design ethos.

building. This also provides an explanation for the disparity in predicted and measured en‐

Monitoring identified several spaces with very good IAQ. Given the prevalence of window opening this result was hardly surprising, but will of course have a thermal penalty. In cir‐ cumstances where window opening is common, the use of an MVHR system is not only in‐ effective but is also an additional primary energy burden on the dwelling as the fan continues to run at the same rate regardless of IAQ conditions. Where window opening was not prevalent, maximum values of CO2concentration were frequently found to rise and be sustained above recognised maximum desirable levels of 1000ppm. Figure 11 illustrates a particular situation from a bedroom in Dwelling 2 over the monitoring period but this is

ergy loads for space and water heating.

typical in monitored apartments throughout the project.

**Figure 12.** Physical parameters in Dwelling 2 twin bedroom – high CO2 concentrations

The bedrooms are of particular interest as windows are generally closed at night due to is‐ sues of external noise and as the occupants are asleep no further occupant intervention oc‐ curs. Accordingly these spaces are entirely reliant to the MVHR system to deliver ventilation

A contributory factor to the poor performance is the layout of the system, with the two air delivery registers focussed into the hall space only.The intention behind this design was that air would migrate from this central location into adjacent apartments. However, fire regula‐ tion requirements for self-closing fire doors and smoke seals prevent such air movement. The situation appears to have been exacerbated post-construction, as carpet installation has

*5.3.2. Internal air quality*

162 Sustainable Energy - Recent Studies

and good IAQ.

*5.3.3. Discussion*

further reduced the air spaces under doors.

A further issue of note in relation to the MVHR system is that of maintenance. The MVHR system contains air filters to screen for dust and particulate and the need ensure these are cleaned on a regular basis is critical to the functionality and energy consumption of the sys‐ tem. In this instance limitation on the space available has led to the placement of the unit in a location above a dropped ceiling where access for maintenance and filter replacement is physically very difficult.

The study identified that through the refurbishment considerable improvement has been made in the thermal performance of the buildings and there should be no doubt that overall it has been successful in terms of the improvement of the flats and the maintenance of the cultural heritage of these buildings.

However, the study also found that there are some problems that lead to a reduced energy performance and some unintended negative consequences, particularly in respect of indoor air quality. These are due to some design issues, for example the fire protection measures over-riding the ventilation strategy; the desire to increase living space in the sun-spaces un‐ dermining the energy strategy (not discussed in this Chapter); the loss of thermal mass through the provision of internal insulation and lightweight sub-division; and the design in‐ tegration of elements such as the MVHR and sunspaces. There are also issues of installation, commissioning and maintenance, including the lack of proper control of the heating system, and MVHR specification and installation.

The study identified a number of measures for improvement, both remedial measures in these flats, but also lessons for similar developments elsewhere.

Options for improvements in this development that are currently being explored include: the re-commissioning and improvement of the heating control systems; an extension of the MVHR supply ducts to deliver air directly into living spaces and bedrooms; provision of ad‐ ditional control over the sunspace extract system.

These findings are also relevant to future developments in this building type. The original building would have had an energy strategy relying on open fires with chimneys providing significant levels of radiant and convected heat, which would engage with the thermal mass of the building. Sash and case windows, although relatively draughty by contemporary standards, provide high and low level openings, which, when combined with high ceilings give very good ventilation regimes. The literature review for this project has highlighted a significant gap in the understanding of the standards of IAQ in energy efficient dwellings and this is a key area for further study. This is relevant to new build energy efficient dwell‐ ings and particularly to retrofit schemes as contemporary approaches may actually reduce IAQ and undermine attempts to improve thermal efficiency and reduced CO2output.

The studies also illustrate the value of information revealed by the use of BPE. Underper‐ forming systems which potentially endangers the health of the occupants will not be appa‐ rent unless the buildings are evaluated in use. Without these studies the conditions in these dwellings would not be known, nor would the knowledge about the issues and how they may be addressed be revealed to the industry in general. In the current low carbon environ‐ ment most new buildings are experiments – it is vital that we go back and check the results. Collectively, the design, installation, maintenance and the need for BPE require further con‐ sideration in order to provide exemplary indoor air quality in Scotland's future housing

The Role of Building Users in Achieving Sustainable Energy Futures

http://dx.doi.org/10.5772/51900

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Mackintosh Environmental Architecture Research Unit, Glasgow School of Art, Glasgow,

[1] Sullivan, L. (2007). A Low Carbon Building Standards Strategy for Scotland, Arcme‐

[2] Shorrock, L. D., & Utley, J. I. (2003). Domestic Energy Fact File 2003. BRE Bookshop,

[3] Boardman, B. (2007a). Home truths: a low-carbon strategy to reduce UK housing emissions by 80 per cent by 2050. Report to the Friends of the Earth and the Coopera‐

[4] Steemers and , K., & Yun, G. Y. (2009). Household energy consumption: a study of the role of occupants', Building Research and Information, doi.org/10.1016/j.enbuild.

[5] The Rebound Effect: an assessment of the evidence for economy-wide energy savings from improved energy efficiency.A report produced by the Sussex Energy Group for the Technology and Policy Assessment function of the UK Energy Research Centre,

[6] http://www.cicstart.org/content/home/1,1,276/FS01DevelopmentofPostOccupancyE‐ valuationforevaluationofinnovativelowcarbonsocialhousingprojects.html

[7] Energy, , Buildings, Volume. 4., Issue, ., & January, . (2011). Measured energy and water performance of an aspiring low energy/carbon affordable housing site in the

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**Author details**

Tim Sharpe

**References**

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The necessity of removal of some of these characteristics (thermal mass, volume of dwell‐ ings through sub-division, high ventilation rates) needs to be considered in taking a holistic approach to refurbishment of these dwelling types which addresses environmental perform‐ ance as well as energy targets.

These questions have wider implications for the profession and identify areas for further re‐ search if we are to achieve the desired sustainable future.
