Impacts on Indoor Air Quality of thermally driven housing retrofit projects in Scotland

With an estimate that over 80% of the houses that will exist 2050 have already been built, the need to undertake retrofit measures is a critical component of strategies to reduce carbon emissions and control fuel poverty. However, given that building regulations do not apply to existing dwellings, the pace of change has been slow. Drivers include revisions of minimum letting standards such as tolerable standards, fuel poverty and eesh. Opportunities include funding packages for particular measures to meet these such as improved insulation. However an emerging concern is that is a fragmented approach that is resulting in piecemeal energy efficiency measures which, although well intended may have unintended negative consequences. This paper discusses a series of case studies of retrofit measures undertaking on a range of building types in the west of Scotland. These have been subject to Building Performance Evaluations which have examined the fabric, ventilation and environmental performance

Ethical issues in domestic building performance evaluation studies

Dwellings are occupied by people and it would seem reasonable to expect that the way they are designed and constructed protects people?s health and wellbeing, and the effectiveness of this would be verified in practice. However, the construction sector is unusual in that is does not routinely evaluate the performance of its artefacts. Thus, when new forms of construction or technology are used, occupants are effectively the subjects of experiments, which raises ethical concerns. Building performance evaluation (BPE) is a critical tool that addresses this problem. This has mainly been conducted by academic organizations, but to be effective BPE needs to become more widely used by design and construction professionals. In these studies occupant behaviour is a key factor and, consequently, occupants are often the focus of studies. Domestic environments are particularly contentious due to the personal and sensitive data that may be collected. Some of the common ethical issues arising from BPE studies in housing are considered. It is argued that if BPE is to become more widely used by industry professionals and their clients, then a wider adoption of ethical policies is needed to protect the participants of such studies, and the practice of BPE itself

The Role of Aesthetics, Visual and Physical Integration in Building Mounted Wind Turbines - an Alternative Approach

There context for addressing energy use in the built environment includes: the climate change agenda; concerns about peak oil supply; increasing fuel costs; costs of de-carbonising grid supply; and security of supply for certain regions. All of these highlight the value and need for renewable energy supplies. The context for the increased development of renewable energy is clear. The balance of evidence coming from the scientific community concerning the threats and impacts of anthropogenic climate change is now widely accepted (IPCC 2007). This had led to an economic analysis of the actions needed to address these problems (Stern 2007), which identify the benefits of early action. In addition to the climate change agenda, other drivers in the form of concerns about peak oil supply in turn leading to scarcity and increasing fuel costs, the costs of decarbonising grid supply, and security of supply for certain regions all highlight the value and need for renewable energy supplies. To address these problems, a range of policies and technologies are being developed to reduce consumption and to provide a greater generating capacity of low carbon and renewable energy. This requires action at a range of scales and across industries, from national generators to individual consumers. The built environment has particular responsibilities with respect to its demand for energy and resources. The majority of the population live in urban environments and buildings account for about 50% the UK energy consumption, and housing produces 27% of CO2 emissions (Boardman 2007). Furthermore, the need for a national grid to serve the built environment, which also results in transmission losses, is also a factor. Energy consumption is based on both space and water heating, and electrical use for lighting, appliances, etc. These demands can be reduced by measures such as improved insulation and air tightness, and this is typified through approaches such as Passivhaus design, which aims to reduce fabric and ventilation losses to a minimum. Further reductions can be made through the use of efficient appliances and controls, but even with these measures residual electrical loads remain. Wind energy is one of the most mature renewable technologies. The development of large scale wind farms both onshore and latterly offshore, provides a significant proportion of the UK renewable energy generation capacity. It is also one of the most visible, and thus in some quarters, contentious generators. However, the use of wind generation in urban environments has increased in scale in recent years and provides significant potential. This chapter discusses the policy drivers and approaches that are forming this market at present

Building Performance Evaluation of a Retrofitted Dwelling in Scotland

It is estimated that 80% of the 2050 building stock already exists and given targets of an 80% reduction of greenhouse gas emissions by 2050, there is a clear need to develop and evaluate retrofitting strategies that reduce energy consumption whilst achieving resilient and healthy indoor environments. This paper presents the results of a building performance evaluation of a retrofitted, Passivhaus certified dwelling in the Orkney Islands (Scotland) during the heating season. The study involved testing of the Mechanical Ventilation with Heat Recovery (MVHR) system, sound assessments, U-Value measurements, energy monitoring, a thermographic survey and indoor environmental monitoring over a three week period. The dwelling had sought to address some ventilation issues identified in other projects by the inclusion of carbon dioxide sensors as part of the MVHR control strategy. The thermal performance of the building envelope and sound level measurements of the MVHR system satisfied the Passivhaus minimum requirements, with acceptable indoor environmental quality observed throughout the monitoring period. However, the results highlighted concerns regarding energy and noise of the MVHR system in boost mode and identified some thermal weaknesses at window seals, and maintenance of the MVHR system in a social housing context. The findings of this study can be used to highlight potential problems and good practice, with the aim of reducing the gap between design intentions and measured performance in future retrofit projects

Health Effects of Modern Airtight Construction: Research Needs and Future Directions

In response to the challenges of climate change, a global shift in building standards and practices is currently underway. In the UK and Ireland, this has been evidenced through substantial improvements of thermal performance and airtightness in new-build and retrofitted dwellings. Whilst improvements in fabric performance should lead to health benefits (particularly for households in fuel poverty), there is now growing concern that the practice of increasing airtightness and limiting ventilation to reduce heat loss may result in indoor air quality problems. These concerns have been exacerbated by reduced space standards, the use of new untested building materials and products, the increasing reliance on mechanical ventilation in new-build housing and the growing housing shortage in the UK. However, while awareness of the risks of increasing airtightness on indoor air quality in housing is growing, there remains a significant lack of evidence of the potential health implications. Research of this nature requires a fundamental understanding of the complex interplay between the climate, building design, occupant behaviour, air quality, toxicology and health

Technologically dependent ventilation in a temperate climate- A UK case study

A fundamental shift in sustainable design thinking and practice has occurred over the last few decades. In particular, the increasing application of heat recovery ventilation (MVHR) is changing the way we envisage the home environment. Instead of passive, adaptive spaces, there is an increasing trend towards the creation of airtight envelopes, where dependence is placed on technological devices to condition the interior environment. This dependence however presents a number of challenges and risks that are of particular concern in a social housing context. This paper discusses the inherent challenges of technologically dependent ventilation in airtight housing in a temperate climate in Scotland. A door-to-door survey was conducted in 36 homes which investigated occupant behaviour and perceptions of ventilation in their home. The study identified issues with occupant use and control of ventilation, with particular concerns relating to the perception of MVHR systems

Scenario Testing of the Energy and Environmental Performance of “The Glasgow House”

This paper describes the results from a 12-month study of two prototype low energy dwellings built for Glasgow Housing Association (GHA). The houses are intended for mainstream and social tenure within Glasgow and contain a range of energy reducing features including one house with a thermally heavy clay block wall and one house using a conventional timber frame and both houses have sunspaces, Mechanical Ventilation with Heat Recovery (MVHR), solar thermal system and low energy lighting. The dwellings have been subject to an innovative monitoring strategy by MEARU, whereby test occupants (students recruited from the School of Architecture) have been asked to inhabit the buildings for six two-week periods using occupancy ‘scripts’ that determine their internal behaviour. The scenarios thus simulate varying patterns of occupancy in both houses simultaneously and the performance of the houses can then been compared. Indications are that although the clay block house had a poorer thermal performance, it did have other qualitative advantages, and consumption differences could be eliminated by exploiting the thermal mass. The performance of the active systems, including the MVHR system, was found to be problematic, and specific scenarios were undertaken to explore the implications of this

Monitored environmental conditions in new energy efficient housing in Scotland – effects by and on occupants

The need to improve building performance to meet the challenges of climate change has led to increasing numbers of low energy houses being constructed and occupied. Given the drivers for rapid change and use of new materials and technologies, it is vitally important that we understand how these buildings are working to ensure that they meet expectations, both in terms of energy use but also liveability, comfort and health from the occupants' perspective. However, unlike other disciplines, construction rarely evaluates the performance of completed buildings. It is crucial that industry adopts these processes. These buildings are in effect a series of experiments, and the occupants are the subjects of these. There is therefore both a practical and ethical need to review the results and to apply this knowledge in future design. This paper presents findings emerging from a two-year Building Performance Evaluation (BPE) study, funded by Innovate UK, of 26 new build low energy houses in Scotland, UK. The programme aimed to develop capacity for undertaking BPE and this research undertook detailed monitoring of energy consumption and internal environmental conditions, as well has gathering information from users about how they use their houses. Although it is clear that housing standards are improving, the study has found evidence of performance gaps between design expectations and actual performance, both in terms of energy and also the quality of the internal environment. This paper will present data from four case study houses, which illustrates both the effects of occupancy on performance, but also how the building performance can affect the occupants’ experience

Building Performance Evaluation, Final Report, Domestic Buildings, Phase 2: In-use performance and post occupancy evaluation, Scotland’s Housing Expo

Scotland’s Housing Expo held in August 2010 in Milton of Leys, Inverness was a high profile event developed to showcase innovative sustainable housing that includes a variety of design ideas and technologies contained within one site (Figure 1:1). This event was the first of its kind in Scotland and was based upon similar Expo models found in mainland Europe and the Nordic countries. The Scottish Expo followed a model from Finland, where historically the ‘Housing Fair’ concept has proven very successful in stimulating high quality design and innovation for housing. The purpose of the Expo was to promote best practice in design with the aim of making sustainable design features commonplace in every home. All dwellings on the site were architect designed, and delivered under a unique design and build arrangement by five developers working together on site in partnership with the local housing agency the Highland Housing Alliance (HHA). The project was completed in 2010 and comprises 27 plots: 26 contain individually designed low energy homes; one plot was undeveloped due to the fact that it proved impossible to reconcile the differential between the project cost as designed with the available budget - this is further discussed in sections 1.3 and 1.4. The Expo was open to the public during the summer of 2010 during which time it generated considerable interest and debate across the architectural, housing and construction sectors in Scotland and the UK. The event attracted over 33,000 professional and lay visitors from home and abroad including visitors from Finland, Russia and Australia. There are 52 houses on the site, 20 for rent/low cost home ownership and 32 houses for sale on the open market. Dwellings demonstrate a variety of layouts and forms designed to minimise energy consumption whilst maximising environmental quality. Contributing energy and environmental features include double height and large volume living spaces, compact form and careful orientation to maximise natural lighting, sun-spaces, external and site design. These houses are now occupied and a living community is developing. During the Expo, visitors were invited to vote for their favourite design - this proved to be a metal and timber clad single dwelling house with a double height living room and a large upstairs hall/study area/play space designed by Malcolm Fraser Architects which is situated on Plot 27. The BPE study was undertaken on eight dwellings: four of these were social rented homes and the remaining four dwellings were owner occupied, sold under a shared ownership scheme. The dwellings selected for study were from four different plots (two dwellings on each plot) each having particular features and design approaches of interest to the construction sector. The comparison of two dwellings from each plot allowed analysis of the effects of occupancy in identically constructed dwellings as well as, a comparison of performance across the differing dwelling designs. The study examined the relationships between design intentions and predictions, impacts of the procurement process, users’ experiences and perceptions of the design, and metered environmental and energy performance. Occupant engagement, in the form of diaries, and the testing of improved occupant guidance were included as part of the project