National Building Stock Research Articles

National-level prediction of expected seismic loss based on historical catalogue

The frequency and severity of natural catastrophes have increased significantly over the last few years, with countries around the world having to face huge economic and human losses. Italy in particular is very seismic-prone, being located in the precise area of convergence between the African and Eurasian lithospheric plates. In addition, most Italian cities are densely populated and have many old and historical buildings, making the country even more exposed and vulnerable in terms of potential losses. Recently, new regulations gave householders the chance to buy insurance against earthquakes. Unfortunately, the widespread risk perception in Italy is very low among the population. In addition, insurance premiums can be extremely high given the low-probability-high-risk of cash flow and insolvency problems potentially incurred by an insurance company if there is a high magnitude earthquake. The aim of the methodology proposed in this paper is to give insurers an engineering instrument with which to quantify expected losses in the case of an earthquake. This will enable insurance companies to model innovative and more affordable financial products by optimizing the quantification of premiums. Seismic events with a magnitude greater than 4 from 217 a.C. to 2012 have been selected from the historical catalogue of the National Institute of Geophysics and Volcanology, and statistical simulations of earthquake scenarios are performed for each of them. In particular, the peak ground acceleration is simulated, based on the ground motion prediction equation of Bindi et al. (Bull Earthq Eng 7(3):591–608, 2009). Actual exposure is assumed for the Italian building stock, which is modelled according to the database of the National Institute of Statistics. Finally, in order to compute the total losses for the entire national building stock, the annual expected losses are quantified according to the procedure demonstrated in Asprone et al. (Struct Saf 44:70–79, 2013).

A Workflow for Automatic Quantification of Structure and Dynamic of the German Building Stock Using Official Spatial Data

Knowledge of the German building stock is largely based on census data and annual construction statistics. Despite the wide range of statistical data, they are constrained in terms of temporal, thematic and spatial resolution, and hence do not satisfy all requirements of spatial planning and research. In this paper, we describe a new workflow for data integration that allows the quantification of the structure and dynamic of national building stocks by analyzing authoritative geodata. The proposed workflow has been developed, tested and demonstrated exemplarily for the whole country of Germany. We use nationwide and commonly available authoritative geodata products such as building footprint and address data derived from the real estate cadaster and land use information from the digital landscape model. The processing steps are (1) data preprocessing; (2) the calculation of building attributes; (3) semantic enrichment of the building using a classification tree; (4) the intersection with spatial units; and finally (5) the quantification and cartographic visualization of the building structure and dynamic. Applying the workflow to German authoritative geodata, it was possible to describe the entire building stock by 48 million polygons at different scale levels. Approximately one third of the total building stock are outbuildings. The methodological approach reveals that 62% of residential buildings are detached, 80% semi-detached and 20% terraced houses. The approach and the novel database will be very valuable for urban and energy modeling, material flow analysis, risk assessment and facility management.

Dynamic simulation of a solar heating and cooling system for an office building located in Southern Italy

The paper investigates the introduction of a solar heating and cooling system in an office building characterized by low energy demand with respect to the current national building stock and located in Southern Italy. Dynamic simulations are carried out in order to evaluate the thermo-economic performance of the analyzed system considering different solar panel technologies (flat plate and evacuated tube), tilt angles (10–70°), collecting areas (30–60m2), hot and cold storage sizes, reference emission factors, electricity and natural gas unitary prices. To satisfy cooling demand a small scale adsorption chiller activated by thermal energy available from solar collectors is considered.The solar heating and cooling system demonstrated primary energy saving and equivalent dioxide carbon emission reduction higher than 23% in comparison to the reference conventional system. The results show that the solar energy system will be competitive when the electricity and natural gas prices will be high and strong government incentives will be provided.

Empirical assessment of calculated and actual heating energy use in Hellenic residential buildings

The gap between calculated and actual energy use has long be recognized as a major hurdle for a realistic assessment of buildings’ performance and anticipated benefits from energy conservation measures, especially when attempting a national building stock analysis. A multinational European effort to develop a conceptual framework for monitoring the effectiveness of energy retrofit measures applied in the European housing sector has motivated a number of national pilot actions. This paper presents the results from the work carried out in Greece and elaborates a methodology for deriving different empirical adaptation factors that relate the normative calculated heating energy consumption from energy performance certificates (EPC) with the actual energy use. To gain some additional insight, the work is complemented by evidence from field surveys to collect actual energy use data from dwellings before and after refurbishment and behavioural surveys of occupants. The derived factors are used to adapt the predictions, which are then organized according to the Hellenic residential building typology. The overall approach is used with a building stock model to demonstrate a preliminary assessment of different energy conservation measures, towards meeting the national targets for 2020 and 2030.The ratio of actual to calculated primary energy consumption using the processed EPC data from over 8500 dwellings, averages 0.56 (i.e. 44% lower energy use than calculated). Findings from field surveys of occupant behavioural changes in the operation of space heating systems, confirm poor indoor thermal comfort conditions resulting from reduced operating hours of space heating, lower thermostat settings etc., which deviate significantly from normative calculation assumptions. Other field data on actual energy use before and after refurbishment provide additional insight for adapting the predicted savings as a result of common retrofit actions. Popular measures include for older buildings the installation of double glazed windows, the replacement of heat production systems and roof thermal insulation. On average, the weather corrected actual primary heating energy savings are about 21% by installing double glazed windows and about 18% by replacing an oil-fired boiler with a new natural gas unit. The application of the results with a building stock model illustrates that future energy and emission targets could be reached with the conservative adaptation factors, but will mandate combined measures and more aggressive modernization rates using an average trend scenario.

Energy mapping of existing building stock in Spain

Energy performance certificate databases are a key tool for mapping national building stock and thus fostering greater overall energy efficiency. This paper presents an insight into the energy performance of residential and tertiary sector buildings in Spain, through an analysis of the first 129,635 energy performance certificates issued for existing buildings, collected by the Catalan Institute of Energy. Most of the residential buildings or building units that were studied were “E” class (53.6%). Single-family houses were found to use more energy on average (248.0 kWhp/m2) than individual dwellings (183.2 kWhp/m2). Tertiary sector buildings were found to have slightly better energy performance (26.4% of buildings were rated “D class”), with an average energy consumption of 317.8 kWhp/m2. Modern buildings consume less energy, as they must meet the higher energy performance requirements stated in thermal building regulations. Residential buildings or building units located in hotter climate zones consume slightly less energy than those located in colder zones, mainly because heating accounts for a high percentage of overall energy expenditure (70–75% in residential buildings). A significant proportion of the energy consumed in tertiary sector buildings is for lighting (37.2%). This research defines the current energy consumption baseline of existing buildings in Spain. The results can help to prioritize energy conservation efforts according to building type, construction period, climate zone and specific end-uses. They may also help public authorities to plan future energy policies, and construction practitioners to identify market segments and business strategies.

Assessment of cost-optimality and technical solutions in high performance multi-residential buildings in the Mediterranean area

The European policy framework is focused on reducing energy consumption in the building sector. The recast of Energy Performance of Buildings (EPBD) Directive establishes that minimum energy performance requirements have to be set to achieve cost-optimal levels.A methodology is developed to assess energy and cost effectiveness in new buildings located in the Mediterranean area. Several energy efficiency technical variants are applied to a multi residential reference building selected as a representative model of the national building stock. Primary energy consumption and global costs are evaluated in a number of configurations to derive the cost-optimal solution.The paper shows how economical high efficient buildings can be obtained at a design stage for a warm climate. The selected configuration decreases primary energy consumption by 90% and CO2 emissions by 88% with respect to the baseline building.Results appear useful for comparison with other climates and building types. The paper also points out that the methodology is suitable to guide and support the choice of cost effective energy efficiency measures in compliance with EU requirements.

A Portuguese approach to define reference buildings for cost-optimal methodologies

The Energy Performance of Buildings Directive (EPBD) recast imposed on all Member States to establish representative reference buildings as an important step in drawing up a methodology for calculating cost-optimal levels of minimum energy performance requirements for buildings and building elements. In this paper, the concept of “reference buildings” and the methodologies used to characterize it are defined. A methodology for defining reference buildings in the national building stock is also proposed. This methodology consists essentially of the creation of a virtual building based on statistical data and, exceptionally, on experts’ knowledge and other sources of information. The parameters necessary for distinguishing samples of buildings and the detailed parameters for characterizing each building are defined and listed. These parameters make it possible to know the most relevant information to be drawn up for each of the buildings and how to standardize the model of data collection for all the existing reference buildings for all categories in the EU. The proposed methodology meets the needs and the existing lack of information in the definition of reference buildings in Portugal. This methodology was successfully implemented so as to define a reference building representative of the residential buildings constructed in Lisbon between 1961 and 1990.

Building-stock aggregation through archetype buildings: France, Germany, Spain and the UK

Knowledge regarding the characteristics of national building stocks is fundamental to understanding how the energy performance of the building stock can be improved. To facilitate large diversity and a number of buildings for such analyses, this paper presents a methodology by which national building stocks may be aggregated through archetype buildings. The methodology has been implemented and verified in four EU countries in regions with different climates, namely France, Germany, Spain and the UK. These countries account for about half of the final energy consumption of the EU-28 buildings. The analysis includes the residential and non-residential sectors (residential sector only for Germany). The number of archetypes per country has been defined according to different categories of building type, construction year, climate region and the main fuel source for heating purposes. The accuracy of the description is validated by simulating energy demand using the ECCABS Building Stock Model, and comparing the final energy demand modeled with corresponding statistical data. The total final energy demand calculated for these countries differs from available statistics by between −6% and +2%, which is considered satisfactory. The proposed description of the building stock is being used as a basis for analyzing the potential for and cost of energy conservation measures.

Use of reference buildings to assess the energy saving potentials of the residential building stock: The experience of TABULA project

Retrofit actions applied to the existent building stock aim at increasing the energy performance, considering the optimal trade-off between energy savings and costs, according to the Directive 2010/31/EU. To select effective refurbishment measures and to quantify the energy saving potentials of the existent building stock, the analysis should be performed on “reference buildings”.This article presents a methodology for the identification of reference buildings, according to the IEE-TABULA project (2009–12) aimed at creating a harmonised structure for “European Building Typologies”. Among the possible applications of the building typology, this work focuses on the potentialities of energy savings and CO2 emission reductions for the European residential building stock. In particular, the Italian approach to model the energy balance of a subset of the national building stock is described; the results show the enormous potentialities of energy savings even with basic energy retrofit actions. Cost analyses were not in the scope of the project, but the results of this study are the basis for further investigations aimed at assessing the cost effectiveness of sets of measures. In this regard, the TABULA building-types are being applied by the Italian government for calculating cost-optimal levels of energy performance, complying with the Directive 2010/31/EU objectives.

Ranking cost effective energy conservation measures for heating in Hellenic residential buildings

Residential buildings comprise the biggest segment of the European building stock and they are responsible for the majority of the building's sector energy consumption and CO2 emissions. This paper documents the potential benefits and sets the priorities of individual energy conservation measures (ECMs) to reduce heating energy consumption in Hellenic residential buildings, including space heating and domestic hot water production. The analysis is facilitated by using the available Hellenic typology for residential buildings that consists of 24 typical buildings, derived after a classification in three construction periods, two building sizes and four climate zones. The focus is mainly on the implementation of ECMs that have low first-cost investment and short payback period. In order to prioritize ECMs that would be most attractive to building owners, two ranking criteria are used, namely primary heating energy savings and payback period. Finally, the preliminary results are used to provide an insight on the potential abatement of CO2 emissions for the national residential building stock.

Field study on the energy consumption of school buildings in Luxembourg

Buildings account for 40% of total energy consumption and 35% of the total CO2 emitted in the EU. In consequence, there is an enormous energy saving potential and the European Union requires from all EU member states to save energy in this sector. Hence, reducing the energy consumption of buildings represents an essential component of environmental protection efforts. Furthermore, the new European directive 2010/31/EU requires that the member states tighten national standards and draw up national plans to increase the number of “nearly zero-energy buildings”. Well-planned energy-saving strategies presume knowledge of specific characteristics of the current national building stock. Therefore, the implementation of a process to support systematic data collection, classification and analysis of the energy consumption of buildings will become increasingly important during the coming years.In the field study described below we analyzed the energy consumption of 68 school buildings in Luxembourg. A separate collation of electricity and heat energy consumptions allowed to make a detailed analysis of specific energy parameters. Clustered according to energy sources, the new buildings were analyzed from a statistical point of view. We defined the energy relevant parameters such as energy standards, the purpose of use of the buildings or whether they had canteens.

The effort to bring existing buildings towards the A class: A discussion on the application of calculation methodologies

The diffusion of the energy certification in Italy is gradually making the users aware of the buildings’ energy performance, at least in some regions. For the existing buildings, the challenge is not only the energy performance calculation, but the analysis of the refurbishment strategies to obtain low energy buildings towards the A class.Basing on European Standards EN ISO 13790 and EN 15316, the Technical Standards UNI/TS 11300 (part 1 and 2) represent the procedures defined at national level. They allow different approaches and levels of simplification in the calculation of various representative energy parameters that could bring to variations in the results.The first aim of the work is the analysis of the most suitable solutions for existing buildings and the real possibilities to move towards the A-class requirements. Another considered aspect is the application of different calculation methods to reach this target, showing how different choices in terms of input data and methodologies (allowed by the Technical Standards) can bring to different values of the energy performance indices. This could represent a problem for the reproducibility of the calculations and their reliability in the definition of the class level reachable through refurbishment.The research has been supported by the analysis of some representative cases of common national residential building stock, comparing the energy performance obtained with different calculation methods allowed by National Technical Standards and laws. The results show some differences which can lead to ambiguities about the class definition and the most suitable methodology to adopt. Some considerations to obtain reliable values of energy performance addressing the refurbishment towards the A class are presented.

QUANTIFYING LIFE CYCLE ENERGY AND CARBON FOOTPRINTS OF CHINA'S RESIDENTIAL SMALL DISTRICT

Whereas current building related life cycle energy and carbon assessment in China has typically focused on either the national building stock or the single building level, this paper attempts to evaluate life cycle energy consumption and carbon emissions at the level of Chinese residential small district (RSD). This paper discusses a case study of RSD in order to illustrate the way of measuring material, energy and water flows at this spatial level with transparent assessment boundary. Results indicate that evaluating the RSD as a whole, rather than building by building, can provide extra decision-making information for various stakeholders such as housing buyers and RSD designers.

Data collection and analysis of the building stock and its energy performance—An example for Hellenic buildings

The process of building labeling and certification in accordance to the provisions of the European Directive on the Energy Performance of Buildings (EPBD) constitutes a unique opportunity for collecting information on the characteristics of the building stock and its energy performance on a national and European level. Thus, there is a need to handle data from a large stock of buildings and to be able to analyse information and extract practical trends and benchmarks. Stakeholders and technical managers who oversee a number of buildings experience similar needs in order to collect, organize and monitor the energy performance of a large pool of buildings. To facilitate these efforts, a common evaluation database and complimentary software for its exploitation have been developed in the frame of a European project. This paper presents an overview of the database and its available tools, and the main results from a case study on Hellenic buildings that reveals relevant characteristics. The Hellenic database included a sample of 250 buildings from different regions in Greece, with a breakdown that is representative of the national building stock. The main results focus on the buildings’ energy performance, thermal envelope characteristics and the exploitation of solar thermal energy.

National building stocks: addressing energy consumption or decarbonization?

The Building Research & Information special issue titled ‘Climate Change: National Building Stocks’ (2007) focused attention on the potential that the national building stock has in reducing CO2 emissions. However, can this potential be realized? To do so requires faith in energy models that suggest that demolition, new build, and the refurbishing of existing homes with insulation measures can deliver massive energy savings by 2050. But why, in the future, can there be increased efficiency and reduced consumption, when this has never occurred in the past? It is argued that the central weakness in the special issue papers is the neglect of the relationship between energy consumption and energy efficiency, and of the ‘rebound effect’. The primary goal, should after all, be to reduce carbon emissions rather than energy use. Hence, emphasis should be placed on decarbonizing the centralized energy-supply systems. However, there will be a role here for micro-generation, building on the favourable image that energy efficiency has amongst the public. In 2050, we may be a low-carbon society, but I doubt we will be a low-energy one. Le numéro spécial de Building Research & Information intitulé « Changement Climatique: le Parc Bâti National » (2007) a attiré l'attention sur le potentiel de réduction des émissions de CO2 que possède le parc bâti national. Cependant, ce potentiel peut-il être réalisé? Pour y parvenir, il faut se fier à des modèles énergétiques qui suggèrent que les démolitions, les constructions neuves et une rénovation des logements existants s'accompagnant de mesures d'isolation peuvent assurer des économies d'énergie massives d'ici à 2050. Mais pourquoi y aurait-il à l'avenir un accroissement du rendement énergétique et une réduction de la consommation, alors que cela ne s'est jamais produit par le passé? Il est argumenté que le point faible central des articles de ce numéro spécial réside dans le fait qu'il n'est tenu compte ni de la relation entre consommation d'énergie et rendement énergétique, ni de « l'effet de rebond». Le but premier devrait être, après tout, de réduire les émissions de carbone plutôt que d'utiliser de l'énergie. De sorte que l'accent devrait être mis sur la décarbonisation des systèmes centralisés d'approvisionnement énergétique. Néanmoins, il y aura là un rôle à jouer pour la micro-génération, en tirant parti de l'image favorable que possède le rendement énergétique auprès du public. En 2050, nous serons peut-être une société à faible émission de carbone, mais je doute que nous devenions une société à faible consommation d'énergie. Mots clés: parc bâti, changement climatique, démolitions, consommation d'énergie, rendement énergétique, faible émission de carbone, mesures politiques, effet de rebond

Decarbonizing national housing stocks: strategies, barriers and measurement

Many nations have set tough targets for reducing the CO2 emissions of their building stocks. The Building Research & Information special issue titled ‘Climate Change: National Building Stocks’ (2007) (volume 35, number 4) describes policy instruments, stock management approaches, and energy supply strategies proposed in a number of counties. Two contrasting propositions for reducing emissions from the UK's housing stock, both based on modelling studies, are discussed in this commentary. One is based on extensive stock management, including increased demolition rates, rigorous energy-efficiency measures, embedded renewable energy generation, and a supportive population. The other is based on the multiplication of more modest improvements in all these areas together with decarbonization of the central electricity supply. Broader sustainability considerations cast doubt on the merits of increased demolition rates, and studies using measured data demonstrate the complex interactions that can occur between embedded energy conversion technologies and the energy supply infrastructure. The commentary highlights some of the barriers to achieving deep cuts in emissions from housing stocks. These need to be examined closely in future research. Equally importantly, there is a need for extensive nationwide monitoring campaigns in order to plan decarbonizing strategies properly and to assess their impact. De nombreux pays se sont fixés des objectifs ambitieux pour réduire les émissions de CO2 de leur parc de logements. Le numéro spécial de Building Research & Information intitulé ‘Changement climatique: les parcs de logements nationaux’ (2007) (volume 35, N° 4) décrit les instruments politiques, les méthodes de gestion de ce patrimoine et les stratégies de fourniture d'énergie proposés dans un certain nombre de pays. Deux propositions différentes de réduction des émissions du parc de logements du Royaume-Uni, toutes deux basées sur des études de modélisation, sont examinées dans cet article. L'une repose sur la gestion complète du parc de logements, y compris l'augmentation du rythme de la démolition, des mesures rigoureuses d'efficacité énergétique, la production intégrée d'énergies renouvelables et une population coopérative. L'autre est basée sur la multiplication d'améliorations plus modestes dans tout ce secteur et sur la décarbonisation de la production centrale d'électricité. Des considérations plus larges de durabilité jettent un doute sur les mérites de l'intensification de la démolition et des études utilisant des données mesurées démontrent les interactions complexes qui peuvent se développer entre les technologies intégrées de conversion de l'énergie et l'infrastructure de fourniture de l'énergie. Cet article met en lumière quelques-uns des obstacles qui empêchent la réduction massive des émissions des parcs de logements. Cette nécessité devra être examinée de près lors des recherches futures. Tout aussi important, on constate qu'il est nécessaire d'organiser d'importantes campagnes nationales de surveillance afin de planifier correctement les stratégies de décarbonisation et d'évaluer leur impact. Mots clés: parc de logements, réduction du dioxyde de carbone (CO2) intensité carbone, changement climatique, démolition, politique de logement, logements zéro carbone

Forum Policy challenges for building stocks

The Building Research & Information special issue titled ‘Climate Change: National Building Stocks’ (2007) (volume 35, number 4) describes the significance of the existing building stocks. Policies that result in integrated, low-carbon buildings and energy systems that provide people with services (e.g., thermal comfort, lighting, and hot water) are crucial for meeting global challenges. In general, it is easier and cheaper to reduce emissions from buildings with energy efficiency and renewables than in other sectors; therefore, it is probable that greater reductions will be required from buildings than from other sectors. Buildings are long lived, so poor policies for buildings will incur a heavy penalty for many decades into the future. Population growth and urbanization are most rapid in developing countries. Therefore, most new buildings will be constructed there and it is vital these have the highest performance. In developed countries populations are almost static and the built environment changes slowly, so the challenge is to improve existing buildings. Policies must be effective in the implementation of well-known energy efficiency and supply measures in buildings, in terms of both installation and operation. Decarbonizing buildings, as indeed the rest of the energy economy, is not so much a technological problem but more of a social and political problem. Le numéro spécial de Building Research & Information intitulé ‘Le changement climatique: les parcs de logements nationaux’ (2007) (volume 35, N°4) décrit l'importance du parc de logements existant. Les politiques qui se traduisent par des bâtiments intégrés sobres en carbone et des systèmes énergétiques qui fournissent des services aux occupants (par exemple, le confort thermique, l'éclairage et l'eau chaude) sont essentielles pour relever les défis d'ensemble. D'une manière générale, il est plus facile et moins cher de réduire les émissions provenant de bâtiments efficaces sur le plan de l'énergie et des renouvelables que dans d'autres secteurs. Il est donc probable que des réductions plus importantes seront exigées du secteur du bâtiment que d'autres secteurs. Les bâtiments ont une longue durée de vie utile et ceux de conception médiocre seront fortement pénalisés pendant de nombreuses décennies à venir. La croissance démographique et l'urbanisation sont plus rapides dans les pays en développement. C'est donc dans ces régions que la construction de bâtiments neufs sera la plus importante et il est essentiel que leurs performances soient les meilleures possibles. Dans les pays industrialisés, la démographie est pratiquement statique et le parc bâti évolue lentement; la difficulté réside donc dans l'amélioration des bâtiments existants. Il faut des politiques efficaces de mise en œuvre de mesures bien connues d'efficacité énergétique et de fourniture d'énergie pour les bâtiments, tant en termes d'installation que d'exploitation. La décarbonisation dans le secteur du bâtiment, comme d'ailleurs le reste du secteur énergétique, n'est pas tant un problème technologique qu'un problème social et politique. Mots clés: parc de logements, réduction des émissions de dioxyde de carbone (CO2), intensité carbone, changements climatiques, démographie, pays en développement, politiques publiques

Retrofitting the existing UK building stock

The recent report of the Intergovernmental Panel on Climate Change (IPCC) confirms both the seriousness of the climate change challenge and the deep carbon emission reductions that are needed to avoid the worst consequences. A large fraction of those emissions come from existing buildings, and the special issue of Building Research and Information entitled ‘Climate Change: National Building Stocks’ (2007) (volume 35, number 4) describes both the range of buildings and emission reduction measures being undertaken in a number of countries. The challenge for the UK is set in an international context. Based on this information, a number of measures are suggested on a national scale that might achieve an 80% reduction in emissions by 2050. Le récent rapport du Groupe d'experts intergouvernemental sur l'évolution du climat (GIEC) confirme à la fois la gravité du défi que pose le changement climatique et l'ampleur de la réduction des émission de carbone qui sont nécessaires pour éviter les pires conséquences. Une partie importante de ces émissions provient du parc de logements existant, et le numéro spécial de Building Research and Information intitulé « Changement climatique: les parcs de logements nationaux » (2007) (volume 35, N° 4) décrit à la fois l'éventail des logements et les mesures de réduction des émissions qui sont mises en œuvre dans un certain nombre de pays. Le défi qui se pose au Royaume-Uni se situe dans un contexte international. Sur la base de ces informations, il est proposé un certain nombre de mesures à prendre au niveau national, qui pourraient permettre d'obtenir une réduction de 80% des émissions d'ici à 2050. Mots clés: parc de logements, réduction du dioxyde de carbone (CO2), intensité carbone, changement climatique, politique publique, Royaume-Uni

Policy and strategy challenges for climate change and building stocks

Issues raised by the papers in the Building Research & Information special issue titled ‘Climate Change: National Building Stocks’ (2007) include the need for an explicitly engineering vision of low-energy and low-carbon futures, the need to develop detailed, dynamic models of the interactions between building stocks and energy supply systems, the importance of data in supporting both the development and the implementation of roadmaps to low-carbon futures, the likely role of micro-generation in low-carbon futures, and the phenomenon of rebound and its implications for energy-efficiency technologies. There appears to be consensus on all but the last two. This paper proposes three alternatives to Saunders' formulation of the Khazzoom–Brookes postulate, based on the view that rebound is only likely to be a problem if energy-efficiency improvements are implemented in the absence of a carbon cap. The paper ends by reviewing the interactions between regulatory and economic environment, culture and technology, and their potential impacts on energy use and carbon emissions. Les questions soulevées par les articles du numéro spécial de Building Research & Information intitulé « Changement Climatique: le Parc Bâti National » (2007) comprennent la nécessité d'une vision permettant de concevoir explicitement un avenir à faible consommation d'énergie et à faible émission de carbone, la nécessité de développer des modèles dynamiques détaillés des interactions entre le parc bâti et les systèmes d'approvisionnement en énergie, l'importance de données permettant d'appuyer à la fois le développement et la mise en œuvre de feuilles de route conduisant à un avenir à faible émission de carbone, le rôle probable de la micro-génération dans un avenir à faible émission de carbone, ainsi que le phénomène de rebond et ses implications pour les technologies à haut rendement énergétique. Un consensus semble exister sur toutes ces questions, sauf les deux dernières. Cet article propose trois alternatives à la formulation par Saunders du postulat de Khazzoom–Brookes, basées sur le point de vue selon lequel ce rebond n'est susceptible de poser problème que si les améliorations en matière de rendement énergétique sont mises en œuvre en l'absence d'un plafonnement du carbone. L'article se termine par l'examen des interactions entre l'environnement réglementaire et économique, la culture et la technologie, et leurs impacts potentiels sur l'utilisation d'énergie et les émissions de carbone. Mots clés: parc bâti, changement climatique, démolitions, consommation d'énergie, rendement énergétique, faible émission de carbone, mesures politiques, effet de rebond

Energy, Carbon and Cost Performance of Building Stocks: Upgrade Analysis, Energy Labelling and National Policy Development

The area of policy formulation for the energy and carbon performance of buildings is coming under increasing focus. A major challenge is to account for the large variation within building stocks relative to factors such as location, climate, age, construction, previous upgrades, appliance usage and type of heating/cooling/lighting system. Existing policy-related tools that rely on simple calculation methods have a limited ability to represent the dynamic interconnectedness of technology options and the impact of possible future changes in climate and occupant behaviour. The use of detailed simulation tools to address these limitations in the context of policy development has hitherto been focused on the modelling of a number of representative designs rather than dealing with the spread inherent in large building stocks. Further, these tools have been research-oriented and largely unsuitable for direct use by policy-makers, practitioners and, ultimately, building owners/occupiers. This chapter summarizes recent initiatives that have applied advanced modelling and simulation in the context of policy formulation for large building stocks. To exemplify the stages of the process, aspects of the ESRU Domestic Energy Model (EDEM) are described. EDEM is a policy support tool built on detailed simulation models aligned with the outcomes of national surveys and future projections for the housing stock. On the basis of pragmatic inputs, the tool is able to determine energy use, carbon emissions and upgrade/running costs for any national building stock or subset. The tool has been used at the behest of the Scottish Building Standards Agency and South Ayrshire Council to determine the impact of housing upgrades, including the deployment of new and renewable energy systems, and to rate the energy/carbon performance of individual dwellings as required by the European Commission's Directive on the Energy Performance of Buildings (EC, 2002).