Dwelling Stock Research Articles

Estimating regional house price levels

While quality‐adjusted indices tracing the evolutions of regional house prices are increasingly available, this is less the case for data on regional house price levels. Yet, such information is fundamental to assess housing affordability and barriers to labour mobility. This article puts forward a method to compile regional house price levels that are consistent with the evolutions given by house price indices, representative of the underlying stock of dwellings, and based on the information on house price levels that is available at all dates rather than in a single reference period. Results for Spain show that the decline in house prices following the 2008–2009 crisis initially reduced the dispersion in house prices across Spanish regions, but this dispersion has increased again afterwards. Moreover, the relative housing affordability of Madrid deteriorated compared to all other Spanish regions in the last decade. Monitoring whether COVID‐19 will reverse this trend will be key.

How much will it cost? An energy renovation analysis for the Portuguese dwelling stock

• Dwelling stock renovation to regulation standards costs a minimum of €71,700 million. • Roof renovation is the most cost-effective measure for improving thermal performance. • Packages of renovation measures result in higher total energy needs reduction. • Renovation in the north inland regions has highest cost-effectiveness. • Older house archetypes have more potential for cost-effective renovation. The building sector is one of the critical pieces for the sustainable transformation in Europe. This study assesses the cost-effectiveness of renovation measures for reducing the Portuguese dwelling stock’s space heating and cooling energy needs at national and regional levels. Three different scenarios with varying renovation levels were developed to identify the most effective interventions, and the building type and regions with the highest improvement potential. The energy needs were computed through a dwelling archetype bottom-up method, using energy performance certificates data. A market-based renovation measure inventory was conducted to estimate investment costs. Results show that a deep energy renovation of the dwelling stock entails a minimum investment of €71.7 thousand million. Roof renovation is the most cost-effective measure for improving heating and cooling thermal performance, respectively 3.5 and 0.8 kWh/€ in the scenarios with lower cost measures. However, renovation packages can add significant marginal increases in energy needs reduction. Results suggest it is more cost-effective to prioritize older house archetypes in the north and south inland regions in the heating and cooling season respectively. These results are informative for more nuanced and targeted policy schemes, enabling more effective use of public funding and increased impact of support measures.

Heating the Dutch housing stock without natural gas

This paper studies the level of improvement of building envelopes required to heat the Dutch housing stock using an energy supply without natural gas, such as a district heating network at lower supply temperature or a heat pump. We identified 35 building types to represent the Dutch housing stock of single-family dwellings. A 4R2C building model was used to assess whether the dwellings could be heated at lower supply temperatures after they were renovated according to six renovation packages of different ambition level.

Log Mean Divisia Index Decomposition Analysis of the Demand for Building Materials: Application to Concrete, Dwellings, and the U.K.

Dwellings are material intensive products. To date, material use in dwellings has been investigated mainly using economic (exogenous) or dwelling (endogenous) drivers, with few studies comprehensively combining both. For the first time, we identify a comprehensive set of such drivers of demand for building materials and analyze them using the logarithmic mean divisia index (LMDI) method. We combine the LMDI method, the concept of dynamic material flow analysis, and physical and monetary flows to decompose the demand for building materials into the following six effects: material intensity, floor area shape, dwelling type, dwelling intensity, economic output, and population. We analyze these six effects on demand for concrete in new dwellings in the U.K. from 1951 to 2014, classified into six dwelling types and four subregions. Of these six effects, the material intensity effect is the most important, overall contributing to increasing concrete demand by +79 Mt from 1950 to 2014, while the dwelling intensity effect plays an opposite role, overall reducing concrete demand from 1950 to 2014 by −56 Mt. The economic output effect is also significant (+38 Mt from 1950 to 2014). A comparative analysis of the six effects in the four U.K. nations reveals that most of the effects arise from England, while the other nations have minor effects due to their smaller populations. Our results show that changes to the demand for concrete in the U.K. fluctuate and have mainly remained between ±30 Mt year–2 from 1950 to 2014, and thus the inflows of concrete into the in-use stock of dwellings have experienced neither entirely increasing or decreasing trends during this period. This study contributes to understanding changes in resource demand due to social, economic, and technological factors and thus improves the capability to reliably and quantitatively model the use of materials in the built environment.

Characterising Brazilian housing through an investigation of policies, architecture, and statistics

Defining common housing characteristics such as typology, floor areas, and occupancy rates can be challenging in many countries because of the prevalence of self-built and/or self-promoted accommodation. Yet, for researchers, designers, and policy makers, an understanding of these is crucial. Although housing represents more than one-third of the entire construction sector in Brazil, the characteristics of these houses vary hugely across the fifty-seven million units that form the existing stock. This variety, mostly a reflection of policies, architectural influences, site restrictions, financial limitations, and irregular planning, is not easily documented. In this article, we attempted to bridge this gap through an investigation of housing policies, architectural practices, and statistical information. This enabled us to identify predominant dwelling types, sizes, occupancy density, and stock availability. In order to contextualise our findings, we compared them with those of other cities around the world. Our findings identified typological patterns, such as rectangular plans, overhangs, small- to medium-sized windows, and design simplicity. We discuss how these are influenced by local architectural traditions and consolidated by housing policies.

A generalisable bottom-up methodology for deriving a residential stock model from large empirical databases

Average reference dwellings representing a predominant housing typology are defined in this work. Specifying such reference buildings is a prerequisite for (i) calculating cost-optimal energy performance requirements for buildings and building elements and (ii) ensuring valid calculations of national building energy consumption. In the EU, an Energy Performance Certificate (EPC) rating is an assessment of the energy consumption of a dwelling. The use of inappropriate default-values for the building envelope thermal transmittance coefficients (U-values) and standardised thermal bridging transmittance coefficients (Y-values) in the production of EPCs leads to an over-estimation of potential energy savings from interventions in the existing dwelling stock. A methodology is presented for the derivation of simplified default-free inputs to a bottom-up residential cost-optimality energy consumption model from an EPC dataset. 35 reference dwellings (RDs) are employed to appropriately characterise 406,918 dwellings. Use of these RDs enable quantification of (i) the energy saving potential of a predominant housing typology, (ii) the effect of default U-value and standardised Y-value use on the prebound effect in dwellings (iii) overall national building energy consumption.

Lisbon After the Crisis: From Credit‐fuelled Suburbanization to Tourist‐driven Gentrification

AbstractThis article examines Lisbon's post‐crisis transition from a once dominant process of suburban expansion enabled by abundant credit to one of ongoing gentrification of its historic centre. In my research, I draw on quantitative and qualitative data to illustrate the remarkable growth of the metropolitan area's population and dwelling stock until the global financial crisis—which affected the Portuguese economy in the course of a process of financialization that relied heavily on the housing industry—and the intensity of urban rehabilitation in subsequent years. However, there is evidence that the latter has not halted nor reduced the loss of long‐term residents in the historic centre, as tourists and other international gentrifiers occupy the upgraded dwelling stock amid an escalation of house prices and rents. The specific contribution of this research lies in the link that it establishes between Lisbon's ongoing process of inner‐city gentrification and the lack of suburban expansion after 2007. By showing that the credit crunch triggered a shift in the geographic location of real‐estate capital that materialized in a new urban development model, this research adds an empirical layer to the study of the spatial effects of the crisis and contributes to the literature on the subsequent restructuring of southern European housing markets.

RESTRICTIVE ZONING’S DELETERIOUS IMPACT ON THE LOCAL EDUCATION PROPERTY TAX BASE

This paper employs a boundary-discontinuity research design to estimate land-use regulations’ causal impact on residential value per student within Massachusetts municipalities. Zoning restrictions hostile toward small dwellings are found to actually reduce residential value per student. This is because small dwellings, although valued less than larger dwellings, house disproportionally fewer school-aged residents than larger dwellings do. It is then shown that restrictive zoning policies, through their mitigating effect on the local stock of smaller dwellings, force municipalities to rely on higher effective property tax rates to self-fund a particular level of per-student education expenditure, holding all else equal.

Estimating urban residential building-related energy consumption and energy intensity in China based on improved building stock turnover model

Accurate estimation of urban residential building-related energy consumption (URBEC) and energy intensity per unit floor area at the national level has significant implications for the analysis of carbon emission peaks. However, reliable data on China's building floor space (BFS) are lacking, resulting in unclear energy intensity levels. This study proposes a China BFS estimation method (CBFSEM) based on improved building stock turnover model. Using CBFSEM, it estimates the BFS of historic urban dwelling stock, the demolished and newly built dwelling from 2000 to 2015. It then estimates the corresponding energy consumption and intensity based on the obtained urban residential BFS data. Results showed that total URBEC in China increased dramatically from 217.1 Mtce in 2000 to 417.2 Mtce in 2015 with an average annual growth rate of 4.45%. China's total dwelling stock almost doubled, from 10.6 billion m2 in 2000 to 27.4 billion m2 in 2015 with an annual growth rate of 6.56%. The operational energy consumption accounted for approximately 70% of total URBEC and the building material production energy intensity was the highest in total URBEC, >60 kgce/m2. A comparison with the China Population Census showed that the deviations were well below 8%, which indicated the reliability of the CBFSEM and the estimated results. In general, this study fills the gap in available data and addresses the shortage of estimation methods for BFS and energy intensity. It also provides the government with technical support and scientific evidence to promote building energy efficiency.

Energy performance progress of the Dutch non-profit housing stock: a longitudinal assessment

Worldwide, buildings consume a large part of the total energy delivered. In the context of all the end-use sectors, buildings represent the largest sector with 39% of the total final energy consumption, followed by transport in the EU (European Union ). A considerable percentage of this energy consumption is attributed to the residential sector. The building sector plays a major role in order to meet the energy saving targets set in the EU and in the Netherlands. This is particularly true for existing buildings, because they will constitute the major part of the housing stock over several decades. The renovation activity is expected to be greater than the construction and demolition activity in the future. Policy targets and regulations are in force at the EU level to ensure the energy efficiency improvement of the building stock. The Energy Performance of Buildings Directive ([EPBD] 2002, recast 2010) is the main legislative and policy tool in EU and focuses on both new and existing buildings. At the same time, the building sector plays a prominent role in the Energy Efficiency Directive ([EED] 2012). Relatedly, in the Netherlands, the foundation of energy efficiency policy has been a number of national cross-cutting measures and EU derived policies that play a large role; like the strengthening of standards for new buildings or dwellings and energy labels for existing ones. The focus of this research is the existing dwelling stock and its energy performance progress. Throughout Europe, national approaches to building stock monitoring have evolved separately. Nevertheless, monitoring the building stocks’ energy performance is gaining attention. Information about the progress of energy performance improvements is not only needed to track the progress of policy implementation, but also better information and data are necessary to help the development of roadmaps towards a more energy efficient building stock. This research seeks to provide insight into the energy performance progress, of the existing non-profit housing stock in the Netherlands, through the application of energy renovations. The non-profit housing stock comprises 30% of the housing market in the Netherlands and a large part of the policies towards a more efficient housing stock rely on the non-profit housing sector. To that end, we determine the energy renovation rate of the stock and the impact of the applied renovations on both the predicted and actual energy consumption. The difference of predicted and actual energy savings is analysed through longitudinal statistical modelling in renovated and non-renovated dwellings. Based on the knowledge gained on the renovation rates of the non-profit housing stock we compare and evaluate future renovation rates through dynamic building stock modelling and empirical data validation. In essence, we examine the effect that the improvement of thermo-physical characteristics of dwellings has on efforts to make the existing housing stock almost emission-neutral by 2050, as advocated by the European Commission since 2011.

Embodied GHGs in a Fast Growing City: Looking at the Evolution of a Dwelling Stock using Structural Element Breakdown and Policy Scenarios

SummaryAfrica is currently experiencing rapid population growth and accelerated urbanization. This demographic shift will require a large amount of new construction material resulting in substantial environmental impact. For many cities on the continent, data gaps make specific quantification and robust prediction of this impact highly difficult. This article presents a method to assess the stock dynamics and embodied emissions of a rapidly growing urban built environment using a bottom‐up, typological approach. This approach allows for the identification of appropriate engineering solutions for decarbonization by localizing embodied greenhouse gas (GHG) emissions in the different constructive elements with a revisited Sankey diagram. Different alternatives regarding housing type and construction techniques are compared. The city of Johannesburg is used as a case study to illustrate the relation between building types, technologies, and embodied GHG of its residential building stock. This new visualization uncovers the most material‐ and GHG‐intense dwelling types and building elements. The adapted Sankey represents the building stock and its drivers in a simple way, allowing clear understanding of the consequences of potential alternatives. The business‐as‐usual scenario indicates 100.5 megatons carbon dioxide equivalent (Mt CO2‐eq) for new construction between 2011 and 2040. The results of the dynamic model over time show that only a combination of a densified building stock with multistory buildings and the use of alternative construction materials and techniques show real potential to decelerate GHG emissions (33.0 Mt CO2‐eq until 2040) while aiming to provide adequate and sustainable housing for all.

Energy performance of dwelling stock in Iceland: System dynamics approach

Despite the significant energy use in dwellings, buildings have the highest energy savings potential among all sectors. One of the main analytical challenges is how to capture the impact from inertia driven by the current dwelling stock. Thus, a dwelling stock model was established to study the impacts of physical processes (e.g., aging), as well as the effect of social processes (e.g., household energy conservation behaviors) on energy demand for space heating in the Icelandic dwelling stock. The model is initialized in the year 2000, and then calibrated with datasets on the Icelandic dwelling stock and hot water consumption for residential space heating. Analysis of the base scenario confirms that the improvement in the average energy intensity of total dwelling stock with regular turnover of the dwelling stock is insignificant and gradual, which relates to the inertia of the existing stock. The comparison of the results from two policy scenarios with the base case, illustrates that the aggressive demolition is more effective compared to the aggressive construction in reducing the total energy demand for space heating. The results of this analysis can support policy makers by providing insights regarding the potential impact of building energy-efficiency policies ensuring an effective policy package.

Using a segmented dynamic dwelling stock model for scenario analysis of future energy demand: The dwelling stock of Norway 2016–2050

The housing sector is important for future energy savings and greenhouse gas emission mitigation. A dynamic, stock-driven and segmented dwelling stock model is applied for dwelling stock energy analyses. Renovation activity is estimated as the need for renovation during the ageing process of the stock, in contrast to exogenously defined and often unrealistic renovation rates applied in other models. The case study of Norway 2016–2050 shows that despite stock growth, the total theoretical estimated delivered energy is expected to decrease from 2016 to 2050 by 23% (baseline) and 52% (most optimistic scenario). A large share of the energy-efficiency potential of the stock is already realized through standard renovation. The potential for further reductions through more advanced and/or more frequent renovation, compared to current practice, is surprisingly limited. However, extensive use of heat pumps and photovoltaics will give large additional future energy savings. Finally, user behaviour is highly important. A strong future rebound effect is expected as the dwelling stock becomes more energy efficient. The estimated total ‘real’ energy demand is expected to decrease by only 1% (baseline) and 36% (most optimistic scenario). Hence, reaching significant future energy and emission reductions in the Norwegian dwelling stock system will be challenging.

Exploring the range of energy savings likely from energy efficiency retrofit measures in Ireland's residential sector

This paper estimates the potential energy savings in the Irish residential sector by 2020 due to the introduction of an ambitious retrofit programme. We estimate the technical energy savings potential of retrofit measures targeting energy efficiency of the space and water heating end uses of the 2011 stock of residential dwellings between 2012 and 2020. We build eight separate scenarios, varying the number of dwellings retrofitted and the depth of retrofit carried out in order to investigate the range of energy savings possible. In 2020 the estimated technical savings potential lies in the range from 1713 GWh to 10,817 GWh, but is more likely to fall within the lower end of this range, i.e. between 1700 and 4360 GWh. When rebound effects are taken into account this reduces further to 1100 GWh and 2800 GWh per annum. The purpose of this paper was to test the robustness of the NEEAP target savings for residential retrofit, i.e. 3000 GWh by 2020. We conclude that this target is technically feasible but very challenging and unlikely to be achieved based on progress to date. It will require a significant shift towards deeper retrofit measures compared to what has been achieved by previous schemes.

Dwelling stock dynamics for addressing housing deficit

Housing in developing countries is often inadequate due to overcrowding, lack of suitable shelter, lack of sanitation and exposure to natural hazards. The United Nations classifies these conditions into two types of deficit: quantitative and qualitative. Strategies for eliminating housing deficits need to consider the dynamics of the total dwelling stock in order to balance this objective with other goals, such as employment in the construction sector, costs, and environmental impacts. Existing dwelling stock models were developed mainly for developed countries and are not suitable to address housing deficits. Here we use a case study for Colombia’s housing stock to propose a dynamic stock model that incorporates deficit. We analyze the evolution of the stock under twelve scenarios combining three projections for household growth and four trajectories for eliminating deficit. The model is calibrated using census data, UN population projections, and own appraisals of household size, based on historical trends. Our results show that closing all deficits by 2030 would require upgrading 2.8 to 3.3 million existing dwellings and building 3.6 to 6.3 million new dwellings, depending on demographics. This represents an increase of 97–155% in construction activity. Conversely, if deficit stays at the current 31% level, 5.1 to 7.9 million households would be in deficit by 2030.

Explaining the historical energy use in dwelling stocks with a segmented dynamic model: Case study of Norway 1960–2015

A segmented dynamic dwelling stock model is proven useful for understanding the development and changes of ageing building stocks, which is highly relevant for renovation measures and estimates of energy use and emissions in aggregated building stocks. In this paper, such a model is developed further for detailed analyses of dwelling stock energy demand and exemplified for the Norwegian dwelling stock 1960–2015. The dwelling stock model simulates the development in stock size and composition and is combined with archetype-specific energy intensities to estimate the total energy demand. After calibrating the model results with statistics, the model is used to explore the phenomena and causes of historical changes. A large-scale improvement of the energy efficiency of the Norwegian dwelling stock has taken place through renovation and construction of new dwellings. A historical shift to more efficient energy carriers and heating systems has had an effect on energy savings in the system, of the same size as the effect of the improved energy efficiency of the stock. However, the total average energy savings per m2 are offset by changes in user heating habits. A significant decrease in average delivered energy intensity per m2 is only observed after the introduction of heat pumps.

Predicting energy consumption and savings in the housing stock: A performance gap analysis in the Netherlands

Residential buildings are one of the key target sectors for energy and CO2 reduction. Research on the relationship between policy instruments and their effects is crucial for the continuous improvement of these tools. This thesis focuses on The Energy Performance of Buildings Directive (EPBD) as an EU flagship policy for technical improvements of the existing dwelling stock. At the core of the directive, an energy certificate is prescribed for all existing dwellings and is required to be present at moments of sale or rent. The certificate includes a theoretical consumption of each individual dwelling. However, theoretical models do not always correspond to reality with the desired accuracy. This large scale study explores the relation between the consumption assumed by the label certificate and the real consumption of the dwellings. It demonstrates that low performing dwellings have a theoretical consumption roughly two times the actual, while well performing dwellings consume one third less. These discrepancies are shown to have adverse effects on policy targets. Therefore, the thesis quantifies the causes of the discrepancies, looking into dwelling and household, as well as behavioural factors. There is a clear need for a more precise estimation of heating consumption on a broader, dwelling stock level in order to enhance the effectiveness of the current renovation policies. The thesis showed that using the current knowledge along with the growing amount of available data, there is enough motivation to reduce the performance gap by improving the predictions of actual dwelling consumption.

Steel Structure Apartment Extensions for Existing Large Prefabricated Panel Collective Dwellings

The Romanian existing building stock of collective dwellings is in a vast majority composed of reinforced concrete large prefabricated panel blocks of flats, erected during Communism. According to the 1992 Census, these standardized and widespread buildings housed almost 60 percent of the urban population of the country.Due to the small, inflexible apartments on one hand and the changing living conditions of the contemporary Romanian society on the other, a need for extending the inner surface of the existing flats has been identified. This situation led to the adoption of technically restrictive ground-floor spatial additions and other vernacular solutions that are being applied to upper stories, some of them not being able to provide, in many cases, any forms of long term structural guarantee to their users.The present paper describes a prefabricated steel structure solution for cantilevered apartment extensions that can be independently attached to the façade, as well as some technical connecting details to the existing building. A global structural analysis performed on a virtual model depicting a widespread type of block of flats (Model 770) proves the non-intrusive influence the cantilevered apartment extensions have over the existing buildings, in multiple different scenarios of attachments. Moreover, a FEM analysis of the proposed details further shows the reliability of the examined solution.

Policy Instruments to Improve Energy Performance of Existing Owner Occupied Dwellings

Policy Instruments to Improve Energy Performance of Existing Owner Occupied Dwellings

Getting Results in an Historical Dwelling Stock in a Thermal Simulation with EnergyPlus

The invaluable historic dwelling stock of many cities today needs an accurate analysis in order to implement a relevant program of research for its conservation, maintenance, or refurbishment. Additionally, energy efficiency studies are essential in every case to guarantee sustainability. In these situations, a simulation process will be a suitable approach to obtaining results. However, historic dwellings are complicated to simulate. They require a comprehensive study of traditional crafts and techniques as well as of ancient constructions which rely heavily on local builders’ design skills and traditions as well as on the regional materials and architectural knowledge. Furthermore, the intricate geometries and the large number of different dwelling cases demand a amplification and a typological definition of representative buildings. In addition, in an energy simulation process, it is indispensable to know what the lifestyle was. In a traditional dwelling, the ancient customs have to be taken into account, studying the occupation, metabolism, activities, and traditional clothing in order to define a reliable computer model. Moreover, an operation usage program has to be defined in order to set other building simulation parameters such as the ventilation, shading, and internal gains. The present work proposes a method using DesignBuilder, an EnergyPlus software package, to generate a model for the energy simulation of historic dwellings through a case study of an historic dwelling stock in the Sistema Central of Spain. How the type was generated from a real case with an architectonic, constructive, and activity definition is described. Guidelines are provided for modeling the building and for setting the simulation parameters necessary to obtain correct results.