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• Overheating regulations and calculation methods in 26 European countries were compared. • Most of the existing calculation methods are outdated and do not fit climate-proof buildings. • France requires a mixed-mode operation of naturally ventilated households. • The UK developed a heatwave-based calculation approach. • Comfort-based, multi-zonal, and time-integrated calculation approaches are needed. With the ongoing significance of overheating calculations in the residential building sector, building codes such as the European Energy Performance of Building Directive (EPBD) are essential for harmonizing the indicators and performance thresholds. This paper investigates Europe's overheating calculation methods, indicators, and thresholds and evaluates their ability to address climate change and heat events. e study aims to identify the suitability of existing overheating calculation methods and propose recommendations for the EPBD. The study results provide a cross-sectional overview of twenty-six European countries. The most influential overheating calculation criteria are listed the best approaches are ranked. The paper provides a thorough comparative assessment and recommendations to align current calculations with climate-sensitive metrics. The results suggest a framework and key performance indicators that are comfort-based, multi-zonal, and time-integrated to calculate overheating and modify the EU's next building energy efficiency regulations. The results can help policymakers and building professionals to develop the next overheating calculation framework and approach for the future development of climate-proof and resilient residential buildings. [ABSTRACT FROM AUTHOR]

This paper provides an analysis of the appliance ownership and use factors contributing to high electrical energy demand in UK homes. The data were collected during a large-scale, city-wide survey, carried out in Leicester, UK, in 2009–2010. Annual electricity consumption and appliance ownership and use were established for 183 dwellings and an odds ratio analysis used to identify the factors that led to high electricity consumption. Many of the appliance ownership and use factors have not previously been studied for the UK domestic sector. The results of this study should be of key interest to government policy makers and energy supply companies interested in the underlying drivers of the highly positively skewed distribution of UK domestic electricity use. The study identifies those appliances that could be targeted for technical improvements or subjected to campaigns to encourage more energy efficient use in order to reduce electricity consumption among high demand households. This paper builds on earlier work by the current authors which identified the households (socio-demographic and dwelling characteristics) most likely to be high electricity consumers. The current work provides the basis for advice and guidance to those households that would enable them to, over time, reduce their electricity use. [ABSTRACT FROM AUTHOR]

Abstract In the UK, housing has been identified as a major sector for contributing to the 80% reduction in carbon emissions over the 1990 baseline by 2050, required by the Climate Change Act 2008. However, pre-1919 housing stock is the least energy efficient and consequently poses challenges to meeting this target. Using a mixed methods approach, the current study demonstrates that, in actuality, there is a significant potential for reducing emissions among this sub-sector of housing, and that the major barriers to energy efficiency retrofits concern a lack of funding, the payback period for the investment, disruption to home life and finding a trustworthy and skilled installer. Moreover, this study finds that homeowners are motivated primarily by the desire to improve home comfort and aesthetics along with a reduction in energy bills rather than in reducing carbon emissions. The paper concludes with recommendations for improving the viability of retrofitting pre-1919 homes through enhanced financial resources, policy support and the promotion of social and economic benefits. [ABSTRACT FROM AUTHOR]

This paper empirically investigates the influence of building fabric, services and occupant related factors on actual energy use of six case study dwellings, located in three new low energy social housing developments in UK, covering a variety of built forms and construction systems (timber frame, hempcrete, steel-frame). Physical monitoring of indoor environment and window-opening is cross-related with building fabric and systems’ performance, and qualitative data gathered through occupant surveys, review of control interfaces and handover guidance, to understand the causes of the gap between modelled and measured energy use. Actual energy use is found to exceed design expectations by a factor of three, questioning the need for whole-house mechanical ventilation heat recovery (MVHR) systems at measured air permeability rates of 6 m³/(h.m²) against the design target of 3 m³/(h.m²). Lack of proper commissioning of MVHR and heating systems, combined with inadequate user comprehension about their operation and control leads to occupant ‘misuse’ wherein systems are de-activated, thereby negatively affecting indoor air quality. This is confounded by occupant factors related to higher demand temperatures, unexpected opening of windows during winters due to under-performance of MVHR combined with habitual behaviours, and over-use of heating systems to compensate for higher than expected air permeability. [ABSTRACT FROM AUTHOR]

This paper provides an analysis of the relationships between dwelling, household and motivation, behaviour and perception characteristics and thermostatic radiator valve (TRV) settings in living rooms ( n  = 187) and bedrooms ( n  = 159) in UK social housing. The work capitalises on primary data from a socio-technical household survey undertaken in Plymouth, UK during 2015, which was coupled with building audit data. The mean reported TRV setpoint temperatures in the living rooms and bedrooms were 23.4 °C and 21.9 °C, implying that occupants prefer cooler conditions in bedrooms. There were systematic variations according to dwelling, household, and motivation, behaviour and perception characteristics. In general, the setpoint temperatures in individual rooms were higher than the whole house thermostat setpoint temperature, implying that there may be a misunderstanding of the role of TRVs in the home heating system. The research could enable social housing providers, the government and commercial organisations to target energy efficiency measures (i.e. thermal upgrades) and social interventions (i.e. behaviour change) at those dwellings and households where their impact may be most beneficial. The results presented could also be used to improve the assumptions of zonal heating behaviour in energy models, which could result in more realistic predictions of the heating demands of social housing. [ABSTRACT FROM AUTHOR]

Abstract: Fossil fuel energy use in heating and cooling buildings is considered to be a major contributor to observed climate change effects, so there is an environmental imperative to reduce energy use in buildings. We should also improve buildings’ energy efficiency on health grounds. Climate change is predicted to produce more frequent extreme weather events, while epidemiological evidence indicates relationships between ambient temperature and ill health. This points to the need for addressing both climate change itself and the way buildings mediate outdoor conditions, for the sake of vulnerable occupants. The UK government requires evidence in support of policy-making concerning energy use in buildings and consequences for health. This paper reviews epidemiological research to illustrate problems associated with measuring the direct health impact of indoor temperatures, for which evidence remains limited. Conventionally, temperature-related health effects are discussed in terms of seasonal excess deaths. The paper goes on to describe a population-based study in London that considers morbidity rather than mortality. A new methodology is developed that links the risk of cold homes with excess winter hospital episodes, demonstrating its potential for identifying small areas for priority action on improving domestic energy efficiency in terms of health as well as the environment. [Copyright &y& Elsevier]

Residential buildings account for significant proportions of energy demand and greenhouse gas emissions. The dwelling and occupants together have a strong impact on the temporal characteristics of energy demand. This paper presents and validates a new stochastic electricity, space heating (SH) and domestic hot water (DHW) model for UK residential buildings, called CREST Heat and Power (CHAP). The open source model is easily adaptable to over 14,000 different building configurations, which represent the UK residential building stock. A validation with empirical data on domestic hot water, gas demand, and internal temperatures demonstrates the accuracy of the new SH and DHW parts of the model. Notwithstanding some uncertainties in extracting the DHW run-off profiles, the energy consumption, water volume, and the dependency on the number of residents are all well considered. The CHAP model produces mean SH, DHW and temperature profiles that are broadly in agreement with the employed field studies. Future work should focus on the consideration of appliances at the heat/power interface, improving the DHW calibration and extending the approach to other national contexts. [ABSTRACT FROM AUTHOR]

This paper presents the methodological approach and findings of a simulation study of advanced energy conservation, generation and management technologies applied to two case study dwellings in the UK, so as to achieve net zero energy (NZE) target that includes a reduction of net regulated energy (HVAC) to 0 kWh/m 2 per year and energy generation of at least 50 kWh/m 2 per year. The performance of the dwellings are also tested for a change in energy use and risk of summertime overheating in future climates in the short (2030s), medium (2050s) and long term (2080s). The findings indicate that to meet the NZE targets, regulated loads need to reduce by about half (over current Building Regulations) with community (rather than building-level) renewables playing a major role. It is also found that the NZE targets, given current regulations, are not particularly difficult to achieve in design with regard to energy efficiency but are highly expectant with regard to renewable energy. Further, summertime overheating is projected to be a risk for net zero energy dwellings by the 2050s. Despite this the regulated energy use of both dwellings is projected to reduce by 11 kWh/m 2 /yr, accompanied by a small increase in renewable generation (2 kWh/m 2 /yr). [ABSTRACT FROM AUTHOR]

Airtightness testing is widely undertaken to assess the as-built performance of dwellings, in support of achieving energy and ventilation strategies. Mandatory schemes operate in some countries, such as the UK, to ensure that dwellings are built in accordance with their design air permeability. However, testing is only useful if the results give a true picture of the airtightness of the building. Previous literature has investigated factors which could influence airtightness test results but has not questioned data quality, despite the pressure on builders to achieve design targets. This paper presents air permeability results from the largest UK dataset, comprising 144,024 dwellings tested under the Air Tightness Testing and Measurement Association (ATTMA) scheme. The data show an unexpected distribution of test results with narrow peaks just within test targets. Such results were not expected theoretically but do reflect findings in other fields where performance-based targets are in place. Such a close match between design and tested airtightness may be achieved by remedial works taking place during the test rather than afterwards. Recommendations are made with respect to quality assurance systems, design guidance and on-site sealing practices to increase the likelihood of long-term airtight buildings being constructed first time. [ABSTRACT FROM AUTHOR]

This paper provides an analysis of the socio-economic and dwelling factors contributing to high electrical energy demand in UK domestic buildings. The socio-economic, dwelling and electricity consumption data were collected during a large-scale, city-wide survey, carried out in Leicester, UK, in 2009–2010. Annual electrical energy demand was estimated for 315 dwellings and an odds ratio analysis used to identify the socio-economic and dwelling factors that led to high electricity consumption. The effects of a number of socio-economic and dwelling factors which have not previously been studied for the UK domestic sector are included. Thus, for the first time, presence of teenagers, having electric space heating as the primary form of heating, portable electric heating and electric water heating were identified as significant drivers of high electricity demand in UK homes. The employment status and education level of the Household Representative Person, the number of floors in a dwelling, presence of fixed electric heating, and the proportion of low-energy lighting were shown to have no effect on high electricity consumption in UK homes. Given the impetus to reduce electricity consumption and CO 2 emissions from the domestic sector, these observations can help shape energy saving campaigns and future energy policy. [ABSTRACT FROM AUTHOR]

Improved methods for quantifying energy savings in buildings need to be supported by empirical measures rather than modeled estimates of future annual energy demand. This paper uses power temperature gradient (PTG, W/K), or the slope of power demand in response to changes in external air temperature; first, to categorise dwelling energy performance from daily energy data (when 0–15 °C outside); second, to investigate variations in 24-h profiles of delivered power. Estimates of PTG were obtained from 567 UK dwellings with 118,000 days of gas and electricity data. From a multivariable regression model, PTG was predicted by dwelling characteristics (number of bedrooms, number of floors, dwelling type, and dwelling age category (all p < 0.001)) but not by number of occupants. When dwellings were grouped into quintiles of PTG, mean PTG had threefold increase from the first to fifth quintile (188 to 563 W/K, respectively). This was reflected in 24-h profiles of delivered power (30 min intervals): at 0 °C, each 100 W/K decline in PTG corresponded to ∼2.5 kW decline in mean morning and evening peak power. Using PTG to estimate reductions in peak power as equivalent ‘negawatts’ reframes potential benefits of energy efficiency retrofits and for grid resilience. [ABSTRACT FROM AUTHOR]

Abstract: In order to reduce carbon emissions and alleviate fuel poverty, the UK Government has outlined proposals for a “Green Deal” to help provide financing for the installation of cost-effective retrofit measures to the existing UK housing stock. However, the Green Deal proposals have the potential to generate financial risk, due to a possible overestimation of the energy savings arising from retrofit measures. This paper proposes a framework for handling the uncertainties associated with the prediction of these energy savings, as well as demonstrating how decisions can be made in the face of the uncertainties involved in the retrofit analysis of a housing stock. The proposed framework is applied to a case study set of dwellings and it is seen that a limited range of measures will be cost-effective under the Green Deal proposals for these dwellings; as a result, subsidies will be required if higher impact measures are to be considered viable. Finally, however, it is also seen that the monetary value of additional societal benefits, such as reduced carbon emissions and improved thermal comfort, is likely to more than outweigh the cost of any subsidies. [Copyright &y& Elsevier]

Abstract: As the debate on policy responses to climate change gathers pace, there has been an increasing focus on tools to model national scale energy use and emission characteristics of UK dwellings. This paper reviews some existing models and highlights limitations of their common underlying methodologies. We argue that a radically different, integrated, approach is required to tackle these challenges and ensure that the modelling remain robust and able to meet future demands. We suggest that Agent Based Modelling (ABM) is a suitable candidate modelling paradigm to achieve an integrated modelling framework. We also present DECarb-ABM (an ABM based implementation of an existing model, DECarb) with many of the desired properties of such an integrated framework. The new model is validated against both the existing model and historical data. [Copyright &y& Elsevier]

Abstract: Heat pumps are an essential technology for decarbonisation of domestic heating in the UK. This paper reports on the performance in use of a group of ground-source heat pumps, and in common with other UK studies finds that the seasonal performance is not as good as that reported in trials from continental Europe and that the system controls are unsatisfactory. Control improvements are investigated via a model of the dwelling and heat pump as a combined system, from which the thermal time constant of the building is identified as a critical factor that needs to be considered in retrofit projects incorporating heat pumps. The validity of the conventional practice (and advice from installers to users) of allowing heat pumps to run continuously is tested and bounded. Techniques for improving control are outlined and reasons for the poorer performance in the UK examined with the conclusion that heat pumps need to be better matched in capacity and control to the size and thermal characteristics of UK dwellings. Implementation of these findings by heat pump manufacturers and installers could promote a more rapid transition to renewable heat both in the UK and internationally wherever similar housing stocks and climates exist. [Copyright &y& Elsevier]

In this paper the findings from a long-term field study of the thermal performance of a circa 1950s dwelling are presented and discussed. The study aimed at evaluating the robustness of the QUB method in the field under UK climatic conditions. A series of 147 QUB tests were performed during the whole heating period (September 2016 – March 2017) in a detached house located in the University Park campus, University of Nottingham considering two distinct conditions: as-built and with increased airtightness. The QUB method was able to provide consistent and robust estimates of the Heat Transfer Coefficient (HTC) of the whole dwelling with approximately 80% of the results within ± 10% from the mean and more than 95% of the results within ± 15%. The need to treat heat losses occurring through the ground when assessing the thermal performance of buildings through experimental diagnostics methods was highlighted, especially in uninsulated concrete slab floors. The method devised to isolate the ground floor heat losses from the whole building losses resulted in reduced dispersion of the adjusted Heat Transfer Coefficient with a coefficient of variation of 5% and 98% of results within ± 10% from the mean. [ABSTRACT FROM AUTHOR]

• Effects of multi-zone heating systems in residential buildings are assessed. • Data obtained from 336 scenarios in Mediterranean climates are evaluated. • Results are evaluated under economic and energy criteria. This paper explores the effects of multi-zone heating systems in residential buildings in different Mediterranean climates. The aim is to evaluate their potential in residential sectors to provide a general basis from the results (from the energy and economic point of view). In addition, if feasible, a further detailed evaluation of this management strategy for optimising the energy use in residential buildings would also be carried out. To do so, the effects of two different zoning controls in different types of apartment, occupancy patterns, building characteristics and locations in Spain, have been assessed. Different combinations of these parameters have resulted in 336 different scenarios that have been dynamically simulated using Design Builder software. The obtained energy results have been analysed in detail. Moreover, an economic analysis of these results has also been carried out to evaluate the economic feasibility of these systems in residential buildings located in temperate climates. This has been calculated by evaluating the maximum investment that can be assumed in each scenario to achieve different payback periods (namely 10 and 20 years). The results obtained show that these systems could be a cost-effective strategy aimed at reducing the energy consumption in residential buildings, not only in cold climates, such as is shown in the literature (the majority of the studies found are located in the UK and northern countries), but also in more temperate climates, such as that of Spain. Savings of around 20% were obtained in the most usual scenarios in Spain (coherent with results obtained in previous studies in the UK found in the literature), showing that in several cases, the initial investment in zone-controlled systems could be paid off in less than ten years, especially in large apartments and the coldest weather conditions. [ABSTRACT FROM AUTHOR]

This paper describes a new method to swiftly model the dynamics of heating energy demand and indoor air temperatures of houses and housing stocks. The Reduced data Energy Model (RdDEM) provides a cost-effective alternative to steady-state modelling by enhancing the input dataset from the Reduced data Standard Assessment Procedure (RdSAP) – the method used to calculate Energy Performance Certificates (EPC) in the UK. This eliminates the main drawbacks associated with dynamic thermal simulation (DTS) of housing stocks, namely the large amount of required input data and the significant time required to model each house. The RdDEM algorithms create RdSAP-equivalent geometry, construction, thermal mass and boundary conditions in Energy Plus DTS software. The new inferences and methodological enhancements were first tested and then implemented at scale using a sample of 83 semi-detached houses. Most energy results from RdDEM were within 10% of those from RdSAP. The differences are explained by the different ways that indoor air temperature is calculated. The RdDEM method provides a dynamic alternative to RdSAP for understanding the dynamics of energy demand and indoor air temperatures in homes. This could include assessing the peak demand of a community energy scheme or assessing the summertime overheating risk in individual dwellings. Ultimately, it could provide a dynamic housing stock model using the data already collected from millions of houses to generate EPCs. [ABSTRACT FROM AUTHOR]