Impacts of energy efficiency retrofitting measures on indoor PM concentrations across different income groups in England: a modelling study

As part of an effort to reduce carbon emissions in the UK, policies encouraging the energy-efficient retrofit of domestic properties are being implemented. Typical retrofits, including installation of insulation and double glazing can cause tightening of the building envelope which may affect indoor air quality (IAQ) impacting occupant health. Using the example of PM (an airborne pollutant with known health impacts), this study considers the influence of energy-efficient retrofits on indoor PM concentrations in domestic properties both above and below the low-income threshold (LIT) for a range of tenancies across England. Simulations using EnergyPlus and its integrated Generic Contaminant model are employed to predict indoor PM exposures from both indoor and outdoor sources in building archetypes representative of (i) the existing housing stock and (ii) a retrofitted English housing stock. The exposures of occupants for buildings occupied by groups above and below the LIT are then estimated under current conditions and following retrofits. One-way ANOVA tests were applied to clarify results and investigate differences between the various income and tenure groups. Results indicate that all tenures below the LIT experience greater indoor PM concentrations than those above, suggesting possible social inequalities driven by housing, leading to consequences for health

Goodbye Warm Front: Evaluating the Delivery of Energy Efficiency Retrofits in Low-income Homes in England from 2005 to 2012

For over 10 years, the Warm Front scheme (WFS) was the primary tool through which Government sought to improve the energy efficiency of owner occupied homes in or at risk of fuel poverty in England. Beginning in 2000, and closing in 2012/13, the WFS provided energy efficient heating and insulation measures to low income households. Targeting and delivery of retrofit measures to vulnerable households is limited by the ability to identify them from available data. Vulnerable households may be ‘unseen’ or be unable to access government programmes because they lack the means or awareness. Key questions to be addressed in evaluating the WFS are: how effective was the targeting in meeting fuel poverty need? How did changes in eligibility affect applications? And, what factors affected application success? A database collected on all WFS applications (successful and unsuccessful) was used to examine the targeting and delivery of measures. The findings show that the uptake of measures among vulnerable households broadly mirrored the concentration of fuel poverty risk across England. Ethnic minority households made fewer applications to the scheme, but were more likely be approved. The WFS was able to treat a significant proportion of the target population over the scheme period examined, over 1.5 million households. However, higher uptake rates were affected by ethnicity, suggesting that engagement may need to be more specifically tailored in the future

Energy Epidemiology: an epidemiological approach to empirically-based population-level energy demand research

The shift to a low carbon economy and the need to address energy demand priorities will involve the retrofit of millions of buildings resulting in changes in energy demand services at the national and international scale. Studying energy demand in buildings at a population level is different than in individual or small samples because of population heterogeneity. Evaluating policies and determining the effect of technologies in situ in millions of buildings means using techniques that support that level of analysis and use empirically derived data that can represent complex real-world conditions. Health epidemiology, which studies the distribution and determinants of population health outcomes, offers a compelling framework for studying population level energy demand. The aim of this thesis is to determine whether the adaption of the conceptual and methodological framework of epidemiology can support the study of energy, people and buildings. This thesis tests this hypothesis by examining relevant epidemiological concepts and its methodological framework along with three studies that adapt and apply epidemiological methods to energy demand and energy efficiency retrofits in UK houses. The method studies use a database of over 13 million dwellings to study energy efficiency retrofit uptake and their impact on energy demand. The method study findings support the case that an epidemiological approach to energy demand provides an appropriate and plausible conceptual and methodological framework for determining population-level evidence to inform modelling and policy development and evaluation. Adapting the epidemiological approach is not a panacea to dealing with the challenges facing the field of research in energy demand in buildings. However, it does provide a set of concepts, methods and analysis tools that are capable of supporting an empirically-based population-level research approach, identified as a necessary step towards to developing a robust foundation of evidence

Ergomorphology: Solar and anthropogenic exposed surface energy balance within the built form of the London urban environment

This study outlines the development of a comparative study of the difference in magnitude of the total incident shortwave solar radiation and the total anthropogenic radiation energy at a built form's given exposed surface area within a representative built form of varying urban environments within the Greater London Authority. The study provides an assessment and quantification of the anthropogenic energy within the GLA, which is rationalized to the highest spatial and temporal resolution possible. The citywide anthropogenic energy is provided at a 1km2 grid. Representative urban environments are assessed and defined based on London's urban characteristics. The anthropogenic energy is then further rationalized to the exposed surface area and compared to of the total incident shortwave solar energy within the representative urban environments. The balance between the two energy sources is compared and the outcome is fit to hourly intensity profiles likely to be seen within the urban environment for different times of the year. The outcome indicates that low-density areas are typically low-rise, predominantly domestic and consume the least amount of energy that medium and high density areas are of varying height, predominantly mixed, and consume a varying amount of energy and, that the very high density areas, with high to high-rise heights, are predominantly non-domestic, and consume a large amount of energy. In addition, the daily exposed surface (wall and roof) energy balance within all representative urban environments is dominated by anthropogenic energy during the winter that during the mid-season the solar and building energy intensity is dependant on density that during the summer, solar energy becomes the dominant energy form within the low to high density areas and, that during an average summer day the roof surface of the very high density area is dominated by the solar energy, but, the anthropogenic energy dominates the canyon surfaces

Health effects of home energy efficiency interventions in England: a modelling study

Objective: To assess potential public health impacts of changes to indoor air quality and temperature due to energy efficiency retrofits in English dwellings to meet 2030 carbon reduction targets. Design: Health impact modelling study. Setting: England. Participants: English household population. Intervention: Three retrofit scenarios were modelled: (1) fabric and ventilation retrofits installed assuming building regulations are met. (2) As with scenario (1) but with additional ventilation for homes at risk of poor ventilation. (3) As with scenario (1) but with no additional ventilation to illustrate the potential risk of weak regulations and non-compliance. Main Outcome: Primary outcomes were changes in quality adjusted life years (QALYs) over 50 years from cardiorespiratory diseases, lung cancer, asthma and common mental disorders due to changes in indoor air pollutants, including: second-hand tobacco smoke, PM2.5 from indoor and outdoor sources, radon, mould, and indoor winter temperatures. Results: The modelling study estimates showed that scenario (1) resulted in positive effects on net mortality and morbidity of 2,241 (95% credible intervals (CI) 2,085 to 2,397) QALYs per 10,000 persons over 50 years due to improved temperatures and reduced exposure to indoor pollutants, despite an increase in exposure to outdoor–generated PM2.5. Scenario (2) resulted in a negative impact of -728 (95% CI -864 to -592) QALYs per 10,000 persons over 50 years due to an overall increase in indoor pollutant exposures. Scenario (3) resulted in -539 (95% CI -678 to -399) QALYs per 10,000 persons over 50 years due to an increase in indoor exposures despite targeting. Conclusions: If properly implemented alongside ventilation, energy efficiency retrofits in housing can improve health by reducing exposure to cold and air pollutants. Maximising the health benefits requires careful understanding of the balance of changes in pollutant exposures, highlighting the importance of ventilation to mitigate the risk of poor indoor air quality

Don’t be late! Findings from reported perceptions and complaints of energy efficiency retrofits in low-income housing in England

Between 2000 and 2013, the Warm Front Scheme sought to reduce heating fuel expenditure in vulnerable households in England, i.e. those on various forms of benefits or income support. The scheme assisted more than 2.4 million households through providing energy efficiency retrofits. An evaluation of the scheme was undertaken for the period 2005-2013 when over 1.5 million households were assisted. During the delivery of the scheme, support was provided for application, installation and post-installation support. Approximately 48,000 households called in to make a complaint during the evaluation period. Using the database of complaints collected by the call centre, the nature, content and issue, and the resolution of the complaint were examined. For households with a retrofit the complaints were connected along with the timing of the complaints. The findings show that while most installations were trouble-free, a substantial minority of customers experienced problems with their installation and that the proportion of complaints increased over the course of the scheme, particularly in the final two years. This appears to be, in part, a result of the increase in complex and major retrofits, but also to be due to complaints from unsuccessful applicants, following tightening of the eligibility criteria. Unsuccessful applicants were, understandably, generally less satisfied. Other areas of dissatisfaction amongst applicants focused around poor communication during wait times, and faults arising with what had been installed. This research examines an often under-reported part of retrofit programmes, i.e. the nature of the complaints related to the delivery of the programme and the retrofits, and how they were dealt with. For scheme designers and providers, understanding what aspects of the programme process are working or not is essential to ensuring a positive re-enforcement around retrofits and their uptake

Energy efficiency in the British housing stock: Energy demand and the Homes Energy Efficiency Database

The UK Government has unveiled an ambitious retrofit programme that seeks significant improvement to the energy efficiency of the housing stock. High quality data on the energy efficiency of buildings and their related energy demand is critical to supporting and targeting investment in energy efficiency. Using existing home improvement programmes over the past 15 years, the UK Government has brought together data on energy efficiency retrofits in approximately 13 million homes into the Homes Energy Efficiency Database (HEED), along with annual metered gas and electricity use for the period of 2004–2007. This paper describes the HEED sample and assesses its representativeness in terms of dwelling characteristics, the energy demand of different energy performance levels using linked gas and electricity meter data, along with an analysis of the impact retrofit measures has on energy demand. Energy savings are shown to be associated with the installation of loft and cavity insulation, and glazing and boiler replacement. The analysis illustrates this source of ‘in-action’ data can be used to provide empirical estimates of impacts of energy efficiency retrofit on energy demand and provides a source of empirical data from which to support the development of national housing energy efficiency retrofit policies

Bridging the Gap: the need for a systems thinking approach in understanding and addressing energy and environmental performance in buildings

Innovations in materials, construction techniques and technologies in building construction and refurbishment aim to reduce carbon emissions and produce low-energy buildings. However, in-use performance consistently misses design specifications, particularly those of operational energy use and indoor environmental quality. This performance gap risks reducing design, technology, sustainability, economic, health and well-being benefits. In this paper, we compare settings of the Chinese and the UK buildings sectors and relate their historical context, design, construction and operation issues impacting energy performance, indoor environmental quality, occupant health and well-being. We identify a series of key, common factors of ‘total’ building performance across these two settings: the application of building regulations, the balance between building cost and performance, skills, construction and operation. The dynamic and complex interactions of these factors are currently poorly understood and lead to building performance gaps. We contend that a systems approach in the development of suitable building assessment methods, technologies and tools could enable the formulation and implementation of more effective policies, regulations and practices. The paper illustrates the application of the approach to the UK and Chinese settings. A full application of a systems approach may help to provide a more dynamic understanding of how factor interactions impact the ‘total’ building performance gaps and help address its multiple causes

Energy efficiency uptake and energy savings in English houses: A cohort study

The UK Government estimates that approximately 22 TWh of energy can be saved from English dwellings by 2020 from a range of fabric and heating energy efficiency retrofits. Yet the rate of retrofit uptake has been less than is needed to meet government targets and the retrofits impact on energy demand has been less than predicted. Two questions that must be addressed are: who have (and have not) taken up retrofits and what household factors affect this; and, what impact have these retrofits had on energy use and how does this differ among households. The purpose of this study is to provide a better understanding of the uptake of energy efficiency retrofits and the resulting change in energy demand. A cohort of 168,998 dwellings gas-heated English dwellings was used to examine retrofit uptake from 2002 to 2007 and the change in gas use from 2005 to 2007. The findings show that retrofits do have an attributable impact on reducing energy demand and that combining retrofits displays a dose-response like effect, after controlling for household and dwelling factors. Energy savings play a central role in meeting UK climate change mitigation targets and therefore understanding the take up of energy efficiency retrofits and their impact on energy demand and variations in these retrofits across the population is vital to understand their potential