Determinants of winter indoor temperatures in low income households in England

The objective of this study is to quantify the extent to which variation in heating season indoor temperatures is explained by dwelling and household characteristics and increased by energy efficiency improvements in low income households. A survey of dwellings in the Warm Front home energy efficiency scheme was carried out in five urban areas of England. Half-hourly living room and main bedroom temperatures were recorded for 2–4 weeks over two winters. For each dwelling, regression of indoor on outdoor temperature was used to obtain estimates of daytime living room and night time bedroom temperatures under standardized conditions (outdoor temperature of 5 °C). The results indicate that the median standardized daytime living room temperature was 19.1 °C and the median standardized night time bedroom temperature 17.1 °C. Temperatures were influenced by property characteristics, including its age, construction and thermal efficiency and also by the household number of people and the age of the head of household. Dwellings that received both heating and insulation measures through the Warm Front scheme had daytime living room temperatures 1.6 °C higher than pre-intervention dwellings, night time bedroom temperatures were 2.8 °C higher. Warm Front energy efficiency improvements lead to substantial improvements of both living room and bedroom temperatures which are likely to have benefits in terms of thermal comfort and well-being.     

Home energy efficiency and radon: An observational study

Exposure to radon gas is the second leading cause of lung cancer worldwide behind smoking. Changing the energy characteristics of a dwelling can influence both its thermal and ventilative properties, which can affect indoor air quality. This study uses radon measurements made in 470 689 UK homes between 1980 and 2015, linked to dwelling information contained within the Home Energy Efficiency Database (HEED). The linked dataset, the largest of its kind, was used to analyze the association of housing and energy performance characteristics with indoor radon concentrations in the UK. The findings show that energy efficiency measures that increase the airtightness of properties are observed to have an adverse association with indoor radon levels. Homes with double glazing installed had radon measurements with a significantly higher geometric mean, 67% (95% CI: 44, 89) greater than those without a recorded fabric retrofit. Those with loft insulation (47%, 95% CI: 26, 69) and wall insulation (32%, 95% CI: 11, 53) were also found to have higher radon readings. Improving the energy performance of the UK's housing stock is vital in meeting carbon emission reduction targets. However, compromising indoor air quality must be avoided through careful assessment and implementation practices.     

Energy Cost Burdens for Low-Income and Minority Households

Abstract

Problem, research strategy, and findings: Of the three primary components of housing affordability measures—rent, transportation, and utilities—utility costs are the least understood yet are the one area where the cost burden can be reduced without household relocation. Existing data sources to estimate energy costs are limited to surveys with small samples and low spatial and temporal resolution, such as the American Housing Survey and the Residential Energy Consumption Survey. In this study, we present a new method for small-area estimates of household energy cost burdens (ECBs) that leverages actual building energy use data for approximately 13,000 multifamily properties across five U.S. cities and links energy costs to savings opportunities by analyzing 3,000 energy audit reports. We examine differentials in cost burdens across household demographic and socioeconomic characteristics and analyze spatial, regional, and building-level variations in energy use and expenditures. Our results show the average low-income household has an ECB of 7%, whereas higher income households have an average burden of 2%. Notably, even within defined income bands, minority households experience higher ECBs than non-Hispanic White households. For lower income households, low-cost energy improvements could reduce energy costs by as much as $1,500 per year.

Takeaway for practice: In this study we attempt to shift the focus of energy efficiency investments to their impact on household cost burdens and overall housing affordability. Our analysis explores new and unique data generated from measurement-driven urban energy policies and shows low-income households disproportionately bear the burden of poor-quality and energy-inefficient housing. Cities can use these new data resources and methods to develop equity-based energy policies that treat energy efficiency and climate mitigation as issues of environmental justice and that apply data-driven, targeted policies to improve quality of life for the most vulnerable urban residents.     

Performance gaps in energy consumption: household groups and building characteristics

ABSTRACT

The difference between actual and calculated energy is called the ‘energy-performance gap’. Possible explanations for this gap are construction mistakes, improper adjusting of equipment, excessive simplification in simulation models and occupant behaviour. Many researchers and governmental institutions think the occupant is the main cause of this gap. However, only limited evidence exists for this. Therefore, an analysis is presented of actual and theoretical energy consumption based on specific household types and building characteristics. Using a large dataset (1.4 million social housing households), the average actual and theoretical energy consumptions (gas and electricity) of different household types and characteristics (income level, type of income, number of occupants and their age) were compared for each energy label. Additionally, the 10% highest and lowest energy-consuming groups were analysed. The use of combinations of occupant characteristics instead of individual occupant characteristics provides new insights into the influence of the occupant on energy demand. For example, in contrast to previous studies, low-income households consume more gas per m² (space heating and hot water) than households with a high income for all types of housing. Furthermore, the performance gap is caused not only by the occupant but also by the assumed building characteristics.     

鲁北乡村住宅的节能设计

农村经济发展,乡村住宅建设量迅速增加,但是乡村住宅在建造和使用过程中能耗过大,阻碍了我国的节能发展.从鲁北地区乡村住宅中存在的问题出发,对乡村住宅的平面设计、层高选择、围护结构保温隔热设计及对太阳能应用设计等充分分析,得出乡村住宅在以上四个方面的节能设计方法,以加快我国的节能步伐.     

Unequal access to energy efficiency in US multifamily rental housing: opportunities to improve

The energy efficiency of US multifamily rental housing is compared with other housing types. A real and growing energy efficiency gap is documented, particularly for lower income households. Findings are based on data from the 2005 and 2009 US Residential Energy Consumption Survey (RECS). Individual energy efficiency features related to HVAC (heating, ventilation and cooling) systems, appliances, and the building envelope are analysed along with weighted and unweighted total energy efficiency indices. Multifamily units occupied by low income renters had 4.1 fewer energy efficiency features in 2005 and 4.7 fewer in 2009 compared with other households. If the number of efficiency features was on par with other housing, the savings could be in the range of US$200–400 per year for most lower-income renters in multifamily buildings. There is an astonishing lack of information on how efficiency retrofits would affect property (real estate) metrics such as cash flow and value. Available evidence suggests that millions of US properties could be good retrofit investment opportunities. Better efficiency would allow renters to increase spending on food, healthcare and other essentials. This is not only an economic issue: it has implications for household health, social equity and environmental problems tied to energy consumption.     

The impact of energy efficient refurbishment on the space heating fuel consumption in English dwellings

The aim of this study is to examine the effect of a major domestic energy efficiency refurbishment programme on domestic space heating fuel consumption. The case study dwellings were monitored either before or after (or both) the introduction of energy efficiency retrofit measures such as cavity wall insulation, loft insulation, draught stripping and energy efficient heating system. Property and utility consumption data were collected and half-hourly living room and main bedroom temperatures were monitored for 2–4 week period over two winters from a total of 1372 households selected from five major urban areas in England. Space heating fuel consumption was normalized to account for variation in the indoor–outdoor temperature difference and the dwelling floor area. The findings show that cavity wall and loft insulation can reduce the space heating fuel consumption by 10% in centrally heated properties and 17% in non-centrally heated properties. However, the introduction of a gas central heating system, although theoretically more efficient, has no significant impact in reducing fuel consumption even after adjusting for increased internal temperature.     

中国传统民居中的被动节能技术

传统民居采取与当地气候相适应的策略,通过自身建筑的处理,以较低的能耗创造出相对适宜的居住环境,对如今的建筑节能仍有积极意义。该文分别从传统民居的用材、保温隔热、自然通风、太阳能利用与遮阳等几个方面分析了中国传统民居中的被动节能技术,以期对现代建筑的节能设计有所启发。     

Energy efficient retrofit of an end of the row house: Confronting predictions with long-term measurements

Looking to the EU's 20/20/20 program, energy efficient retrofitting will be a key element in the 20% less primary energy in 2020 compared to business as usual. Within that context, field studies that put realizable efficiency in perspective are urgently needed.The dwelling evaluated was built in 1957. In those days energy efficiency was no concern. Houses got no insulation, ventilation was adventitious and heating systems scored badly. The retrofit started in the early eighties, stepwise as to follow the impact of separate measures on heating energy consumed. A solar boiler was installed in 2004. PV followed in 2009. The first 19 years a family of five inhabited the dwelling, then the parents only. Monitoring started in 1978.In the paper, predicted annual energy for space heating is compared with monitored result. The measured data, though showing a net decrease, consistently underscore predictions. Main reason is direct rebound. The benefits of the solar boiler and PV-panels are minimal compared to the energy avoided by better insulation, energy efficient windows, better air-tightness and upgraded ventilation and central heating. However, targeting passive house and zero energy quality is beyond optimal in terms of net present value and not doable in the dwelling.     

山东省居住建筑节能75%设计标准和德国建筑节能标准对比分析

对比山东省居住建筑节能75%设计标准与德国相关标准,发现我省建筑节能设计标准尚有需要提高的地方。以某多层住宅为例,计算我省75%节能标准,德国2002年、2009年节能标准,以及被动式建筑节能设计标准的供热需求量。探讨了我省建筑节能标准再提高的技术路线图,包括使用高性能围护结构保温产品,减少新风耗热量所占比例,提高建筑物整体气密性等应对策略。     

Indoor air quality in energy‐efficient dwellings: Levels and sources of pollutants

Worldwide, public policies are promoting energy‐efficient buildings and accelerating the thermal renovation of existing buildings. The effects of these changes on the indoor air quality (IAQ) in these buildings remain insufficiently understood. In this context, a field study was conducted in 72 energy‐efficient dwellings to describe the pollutants known to be associated with health concerns. Measured parameters included the concentrations of 19 volatile organic compounds and aldehydes, nitrogen dioxide, particulate matter (PM_2.5), radon, temperature, and relative humidity. The air stuffiness index and night‐time air exchange rate were calculated from the monitored carbon dioxide (CO₂) concentrations. Indoor and outdoor measurements were performed at each dwelling during 1 week in each of the two following seasons: heating and non‐heating. Moreover, questionnaires were completed by the occupants to characterize the building, equipment, household, and occupants’ habits. Perspective on our results was provided by previous measurements made in low‐energy European dwellings. Statistical comparisons with the French housing stock and a pilot study showed higher concentrations of terpenes, that is, alpha‐pinene and limonene, and hexaldehyde in our study than in previous studies. Alpha‐pinene and hexaldehyde are emitted by wood or wood‐based products used for the construction, insulation, decoration, and furnishings of the dwellings, whereas limonene is more associated with discontinuous sources related to human activities.     

Transport,Housing and Urban Form: The Life Cycle Energy Consumption and Emissions of City Centre Apartments Compared with Suburban Dwellings

Buildings in cities and the activities carried out therein use a significant proportion of a nation's energy consumption and produce substantial quantities of greenhouse gases in the process. Residential buildings are a large contributor, partially as a result of the transport and housing activities of households. In this study, life cycle analysis is used to calculate the total transport and housing energy and emissions from a sample of 41 households in apartment buildings in the city centre of Adelaide, Australia and compare them with suburban households. The purpose of this is to determine whether the urban density option of higher rise dwellings offers a lower environmental impact than conventional housing. The analysis includes delivered energy and greenhouse gas emissions generated by motorised travel and activities within the dwellings, and the energy and emissions embodied in household motor vehicles and the apartment buildings. The total delivered energy consumption of apartment households was found to be lower than suburban households due mainly to higher car usage, particularly in the outer suburbs. However, the analysis of total greenhouse gas emissions provided a somewhat different comparison especially when they were considered on a per capita basis. The total per capita emissions for apartment households varied considerably but, on average, exceeded those of both the inner and outer suburban households. This resulted from lower occupancy rates and higher emissions arising from higher dwelling operational and embodied energy consumption. Overall, it cannot be assumed that centralised, higher density living will deliver per capita emission reductions for residents, once the combined per capita life cycle emissions from housing and transport have been accounted for. A more vigorous educational, promotional and regulatory approach is required to achieve greater operational and embodied energy efficiency in apartment buildings to fully realise the emissions-reducing potential of such buildings in centralised locations.

     

The impact of climate change uncertainties on the performance of energy efficiency measures applied to dwellings

European Union and UK energy policy recognise the potential contribution the domestic sector can make in reducing energy consumption. In the UK, improvements to existing dwellings are likely to play a critical role in realising such potential.There is growing evidence that the global climate is changing. In the UK, projected climate changes could have a considerable impact on the thermal performance of the built environment and on measures implemented to improve such performance.Building simulations designed to investigate the potential impact of climate change uncertainties on the performance of insulation measures, applied retrospectively to an existing residential dwelling, suggest their effect could be considerable. Thermally, double glazing is the best option because although it is more sensitive than the others to climate change, it still delivers the highest savings in heating energy demand for the lowest induced cooling load. Loft insulation is the worst option in thermal terms.     

中国传统民居院落与气候浅析

中国大部分地区的民居都采用了院落式布局方式。不同地域的民居院落为了适应当地的气候条件、社会风俗、生活习惯等呈现出千姿百态的形式,其中气候因素起到了关键作用。该文通过我国不同气候区的6个典型民居院落,分析庭院面积、庭院形状、庭院周围建筑外墙、开窗、屋顶形式与气候的关系。     

Key factors determining the energy rating of existing English houses

In the UK, the Standard Assessment Procedure (SAP) is used to rate the energy performance of existing dwellings whenever they are let or sold. This study investigates which of the inputs to SAP account for the most variance in energy rating across existing gas central heated houses in England. Data from the English Housing Survey (EHS) 2009 are used to generate a representative set of dwellings and variance-based global sensitivity analysis is then applied to assess each input's contribution to the variance in the calculated ratings. It is demonstrated that heating system efficiency, external wall U-value and dwelling geometry account for 75% of the variance of the energy rating of gas central heated houses in England. This suggests that improving heating system efficiencies and wall U-values of the worst performing dwellings will go a long way towards improving their energy rating and potentially reducing their energy consumption. It is also demonstrated that dwelling geometry has a much bigger influence on the calculated carbon emissions (accounting for 80% of the variance) than it does on the SAP energy rating (accounting for 30%), meaning that significant improvements in energy rating might not be accompanied by significant reductions in carbon emissions.     

在长江流域及周围地区组织实施《夏热冬冷地区居住建筑节能设计标准》的意义和作法

建设部制定的《夏热冬冷地区居住建筑节能设计标准》，对长江流域及周围居住建筑从热工和暖通空调设计方面提出了节能措施和能耗控制目标，并制定了节能设计性能指标。实施这一标准后，该地区人民居住环境质量有望得到改善和提高。     

Real-life energy use in the UK: How occupancy and dwelling characteristics affect domestic electricity use

The patterns of electricity consumption were studied for 27 representative dwellings in Northern Ireland. The type of dwelling, its location, ownership and size, household appliances, attributes of the occupants including number of occupants, income, age and occupancy patterns have differing but significant impacts on electricity consumption. A clear correlation was found between average annual electricity consumption and floor area. The monthly consumption of detached houses is between 3.57 and 5.17 kWh m⁻²; semi-detached between 3.44 and 4.59 kWh m⁻² and terraced houses between 2.5 and 3.9 kWh m⁻². The average winter consumption exceeded the average summer consumption by 1.59 kWh m⁻² for detached, by 1.16 kWh m⁻² for semi-detached and by 1.78 kWh m⁻² for terraced houses. The difference in the annual demand on the grid between detached and terraced houses is between 24 and 30%. The electricity consumption per person decreases as the number of occupants increases. This is particularly significant in large dwellings but smaller numbers of occupants.     

Appropriate energy efficient building envelope technologies for social housing in the Irish climate

Extensive dynamic thermal simulation parametric analyses have been undertaken of energy efficient fabric alterations to social housing in Northern Ireland culminating in priorities for deployment. Five ȁ8basecaseȁ9 simulation models were used to represent the predominant characteristics of the existing social housing stock. The majority of technologies studied provided annual space-heating energy savings of more than 10%. The variation of energy savings and economic performance across the basecases highlights the value of a dwelling specific approach to selecting energy efficient building envelope technology solutions for energy rehabilitation programmes. The paper further outlines a framework for prioritising appropriate energy efficient building envelope technological solutions for a large regional building stock, i.e. existing social housing stock in Northern Ireland, highlighting influential parameters. An energy efficient building envelope inter-technology ranking approach provides a method of comparison across the various different dwellings in the regional housing stock. Airtightness ranked consistently highest across the dwellings studied with some solar technologies performing better than more technologically mature solutions such as insulation.     

Modelling the impacts of building regulations and a property bubble on residential space and water heating

This paper develops a bottom-up model of space and water heating energy demand for new build dwellings in the Irish residential sector. This is used to assess the impacts of measures proposed in Ireland's National Energy Efficiency Action Plan (NEEAP). The impact of the housing construction boom, which resulted in 23% of occupied dwellings in 2008 having been built since 2002, and the subsequent bust, are also assessed. The model structure treats separately new dwellings added to the stock after 2007 and pre-existing occupied dwellings. The former is modelled as a set of archetype dwellings with energy end use affected by the relevant set of building regulations that apply during construction. Energy demand of existing dwellings is predicted by a simpler top down method based on historical energy use trends. The baseline scenario suggests residential energy demand will grow by 19% from 3206 ktoe in 2007 to 3810 ktoe in 2020. The results indicate that 2008 and 2010 building regulations will lead to energy savings of 305 ktoe (8.0%) in 2020. Had the 2008 building regulations been introduced in 2002, at the start of the boom, there would be additional savings of 238 ktoe (6.7%) in 2020.     

The impact of energy externalities on the cost effectiveness of energy efficiency measures applied to dwellings

European Union and UK energy policy recognise the potential contribution the domestic housing sector can make in reducing energy consumption. In the UK, improvements to existing dwellings are likely to play a critical role in realising such potential. The need to consider both the value and uncertainty of external environmental and social costs in developing effective policy is also made explicit.This analysis investigates the impact of such values and uncertainties on the relative performance of a range of insulation measures applied retrospectively to an existing residential dwelling.Results from a case study suggest that large variations in capital cost, energy saving potential and the value of externalities have a significant impact on the relative cost effectiveness of these measures. However, in general, current investment decision-making based on normal market energy prices and today's climate is likely to deliver solutions that remain effective under significant levels of uncertainty.