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Purpose: Despite the number of quality management procedures being currently applied, construction defects in the domestic sector are acknowledged to contribute to the energy performance gap of buildings. This paper investigates the limitations and challenges to the implementation of project quality plans (PQPs) and their impact on the achievement of expected thermal performance in the UK social housing projects. Design/methodology/approach: A qualitative approach, guided by grounded theory, was used in this research. This methodology provided the structure for systematic data analysis iterations, enabling cross-case analysis. An analytic induction process was designed to seek the explanation of the targeted phenomenon and required data collection until no new ideas and concepts emerged from the research iterations. This study collected data from five social housing projects through interviews, site observations and project documentation. Findings: Multiple limitations and challenges were identified in the implementation of PQP to deliver thermal efficient social housing. Generally, there is the need for more objective quality compliance procedures based on required evidence. When investigating the root of the challenges, it was concluded that the adoption of statutory approval as the main quality compliance procedure led to the dilution of the responsibility for prevention and appraisal of defects that compromised the effectiveness of PQP devised by housing associations (HA) and contractors. Originality/value: This study identifies the shortcomings of PQP in addressing quality issues with potential to undermine the thermal performance of social housing projects. The findings could be used by HA, contractors and policymakers as steppingstones to improve the energy efficiency in the domestic sector. [ABSTRACT FROM AUTHOR]

Energy use in buildings accounts for one-third of the overall global energy consumption and total building floor area continues to increase each year as new developments are constructed and delivered. If stringent climate goals are to be met, these buildings will need to consume less energy and emit less carbon. However, design intentions for energy efficient buildings are not always met in practice. This performance gap between calculated and measured energy use in buildings threatens the progress necessary to meet these energy targets. The aim of this paper is to identify the factors that contribute to the performance gap and propose solutions for reducing the gap in practice. A quantitative and qualitative analysis of two research programmes completed in the past few years was utilized for an in-depth look at the performance of around 50 non-domestic buildings in the United Kingdom. While no direct links were found between any one variable and the performance gap, several correlations exist between contributing factors indicating a complex, entangled web of interrelated problems. The multitude of the variables involved presents a formidable challenge in finding practical solutions. However, the results indicate that the combination of the ventilation strategy of a building and the building services control strategy during partial occupancy is a key determinant of the performance gap. A more straightforward procurement approach with clearly delineated targets and responsibilities, along with advanced and seasonal commissioning instituted at the beginning of a project and implemented after building completion can also be very effective in reducing the gap. Finally, mandatory requirements or an appropriate system of incentives for monitoring and disclosure of performance data can help identify many of the underlying issues affecting performance in-use and untangle some of the web of complex issues across the building sector. Practical application: Awareness of the performance gap and knowledge of the factors contributing to its impact on the building industry is important for all stakeholders involved in the design, construction, operation and occupation of non-domestic buildings. Understanding potential solutions to mitigate these risks may help to reduce the prevalence and magnitude of the performance gap. [ABSTRACT FROM AUTHOR]

The potential of normative and feedback (financial vs. environmental) information in guiding pro-environmental decision-making behaviour was explored in a 2 × 2 (plus control) choice experiment. Using the context of home heating, 599 non-student participants from the UK general public were asked to choose between a standard heating system (a gas boiler) and a relatively more-energy efficient option (a heat pump). In line with evidence for the energy efficiency gap for sustainable innovations, there was low uptake of the heat pump (32.5%) in the control condition where no frame information was provided. Yet, in both conditions where normative information was provided, respondents were significantly more likely (vs. control) to choose the heat pump (financial + norm OR 3.63; 95% CIs 2.13,6.19; environmental + norm OR 3.09; 95% CIs 1.67,4.79), advancing understanding of normative social influence in the context of pro-environmental purchase behaviour. When normative information was not provided, only financial (OR 2.82; 95% CIs 1.67,4.79) but not environmental (OR 1.33; 95% CIs 0.78,2.26), feedback was associated with a significantly greater likelihood of heat pump choice. The main effect of normative information was replicated for behavioural intentions (though only for homeowners), but there was no norm-feedback interaction (regardless of homeownership). The implications for researchers looking to promote 'green' choice in the context of new technology adoption are discussed. • Empirical exploration of alternate decision frames in promoting 'green' choice. • Focus on context of energy-efficient versus standard technology adoption in homes. • Normative info increased likelihood of 'choosing green'; overruling feedback type. • Financial feedback most effective in changing behaviour when no norm info is given. • Implications for behaviour change efforts in this context are discussed. [ABSTRACT FROM AUTHOR]

• A well-functioning space heating system can operate below 70 °C for 98% of the year and below 55 °C for 71% of the year. • The performance gap between measured and calculated energy use is widening across building age groups, with a clear increase for post-1980 buildings. • Pre-1980 buildings can operate with supply temperatures below 70 °C for 96–99% of the year and below 55 °C for 67–71% of the year. • Building envelope improvement, whilst recommended, is not a pre-requisite for using low-temperature supply in pre-1980 buildings. • Post-1980 buildings could have limitations in respect of using low-temperature heat under windy conditions. Decarbonising heat in the UK by 2050 will require the wider adoption of low-temperature heat. Current systems, largely relying on gas boilers, have design operating temperatures of 82/71 °C (supply/return) while new standards for 4th Generation District Heating are 55/25 °C. Local authorities must set-up strategies to get their buildings "Heat network ready" but this raises the question of the ability for existing buildings to use low-temperature heat. The aim and the novelty of this paper is to establish a relationship between an energy 'performance gap' in Scottish public buildings and their ability to use low-temperature heat. This performance gap has been evaluated for 121 non-domestic buildings, primarily schools, operated by The City of Edinburgh Council. Space heating system are assumed oversized by 10%. The results show that renovation of the building envelope, while highly desirable, is not a pre-requisite for using low-temperature heat in pre-1980 constructed buildings, which represent 64% of the stock. It also highlights that post-1980 buildings, predominantly utilising mechanical ventilation systems, demonstrate an increasing performance gap which could limit their ability to use reduced operating temperature, especially in windy conditions. [ABSTRACT FROM AUTHOR]

Solid wall dwellings in the UK are in urgent need for energy retrofit to support achieving the UK net-zero strategies in the building sector and reduce fuel poverty. Several barriers are a cause of uncertainty for householders about Solid Wall 1nsulation (SWI) and slow down the progress. This paper aims to examine people's perceptions of possible inclusion of aesthetics elements in Internal Wall Insulation (IWI), providing a suitable solution to promote wall insulation intake and attractiveness. To achieve this aim, first, the current literature is critically reviewed and analysed to highlight the gap between energy studies and design/aesthetic features of SWI retrofit. Then, an online survey is conducted, and the collected data are analysed. The results show that the aesthetic factor is very important for participants with more than 90% agreement. This level of agreement is as high as other well-known critical factors in renovation such as cost and energy saving. Also, aesthetic integration in IWI can surpasses negative concerns such as the retrofit cost or losing internal space. Furthermore, over 2/3rd of participants are in agreement with a suggested business model for delivering both aesthetic and energy improvement in combined retrofit plans by established approved organizations. It is concluded that aesthetic inclusion is the priority and an encouraging factor in the internal renovation to reduce the barriers and increase success. Finally, the findings from this research pointed to how the retrofit industry, policymakers, and designers should evolve to achieve the benefits of aesthetics in SWI. • Critical literature review on energy studies and aesthetic features of SWI retrofit. • Examine people's perceptions of aesthetic inclusion in Internal Wall Insulation. • Examine the aesthetic effect on users' preferences in an internal renovation. • Examine aesthetic success to surpass negative aspects of IWI. • Recommend how the stakeholders evolve to achieve the benefits of aesthetics in SWI. [ABSTRACT FROM AUTHOR]

Homes contribute 22% of UK carbon emissions, 45% of which are primarily for space heating energy. Delivery of highly insulated homes, new build and retrofit, is needed to help meet the UK's 2050 net zero carbon target. Similar policies are being adopted across the developed world to limit rising carbon emissions. Unfortunately, most new and retrofitted buildings use much more energy than predicted by computer models at design stage, up to 250% more, the so-called 'energy performance gap'. Although emerging evidence suggests that buildings built to the low-energy Passivhaus standard do not demonstrate such a gap, data are often from small-scale forensic investigations. Here, we present the first large-scale systematic evaluation of this standard in occupied buildings using multi-year data from 97 UK Passivhaus dwellings spread across 13 sites. As frequency and type of data collection varies between sites, we adopt a pessimistic approach to the analysis by systematically over-estimating space heating demand in the presence of uncertain data. Results pooled across multiple years, show that mean observed space heating demand is 10.8 kWhm2a−1 (SD 9.1) with no statistically significant difference against predicted demand of 11.7 kWhm2a−1 (p = 0.43, d = −0.1). These results provide powerful evidence in favour of the Passivhaus standard as a reliable means of obtaining low-energy and low-carbon buildings and should be seen in the context that the estimated space heating demand of the average UK home is currently about 145 kWhm2a−1 and a new build home predicted to be 50 kWhm2a−1 and likely to be much more. [ABSTRACT FROM AUTHOR]

The energy performance gap in buildings is a well-known phenomenon. However, its actual definition and extent is dependent on the baseline used for defining the gap. In this paper a calibration-based methodology is used to identify and validate the root causes of the performance gap. Following analysis of the performance of four case studies in the UK, from different building sectors, cross sectoral learnings that are applicable in the wider industry context are uncovered. Through the model calibration process and in the overall performance assessment, Indoor Environmental Quality (IEQ) parameters have been used to improve the robustness of validation of the calibrated models and to highlight the interrelationship of energy and IEQ. The study shows the importance of contractual accountability to minimise performance issues, building a case for having IEQ in energy performance contracts to manage the trade-offs of IEQ against energy performance that leads to unintended health consequences for the occupants. [ABSTRACT FROM AUTHOR]

The structural, electronic, and optical features of CsPb(I 1-x Br x) 3 (x = 0, 0.25, 0.50, 0.75, and 1.0) compounds were evaluated using first-principles calculations based on the full-potential linear augmented plane wave (FP-LAPW). The ground-state properties were examined, with a focus on the structural, electronic, and optical properties of the compounds. The structural features were computed using the PBE-GGA potential, revealing that both the lattice constant and bulk modulus varied nonlinearly with respect to the bromide concentration. Theoretical X-ray diffraction analyses revealed peak shifts to larger angles when the average fraction of bromide incorporated increased, indicating shrinkage in the lattice. While the E g values were calculated using the PBE-GGA potential and resulted the 1.45, 1.43, 1.53, 1.50, and 1.77 eV values, the mBJ-GGA potential values resulted the 1.90, 1.81, 2.11, 2.12, and 2.50 eV for CsPbI 3 , CsPbI 2.75 Br 0.25 , CsPbI 1.5 Br 1.5 , CsPbI 0.25 Br 2.75 , and CsPbBr 3 respectively. In addition to that, the E g values of CsPbI 1.5 Br 1.5 which were calculated using other potentials: LDA and PBEsol potentials have resulted the 1.43 and 1.49 eV values, respectively. The E g of CsPb(I 1-x Br x) 3 obtained using mBJ-GGA potential has relatively matched with previously reported experimental values. The calculated effective masses are highly correlated with the energies of E g, the valence-band maximum (VBM), and conduction-band minimum (CBM). We observed that there was an increase, with small bowing parameters (b), in E g value as the Br concentration increases in the CsPb(I 1-x Br x) 3 compounds. The semiconductor characteristic was prominent in the observed band profiles when PBE-GGA and mBJ-GGA potentials were applied. Additionally, the optical properties were examined in details. The calculations indicate that the CsPb(I 1-x Br x) 3 compounds are promising candidates for optoelectronics. Image 1 • The structural, electrical and optical properties of CsPb(I 1-x Br x) 3 were investigated using the PBE-GGA and mBJ-GGA. • An increase in the band gap energy (Eg) values of 0.32 eV (PBE-GGA) and 0.60 eV (mBJ-GGA) when substituting I with Br. • The calculated band gap (Eg) values using the mBJ-GGA were better matched with the experimental values. • The effective masses of electron and hole were calculated using PBE-GGA and mBJ-GGA potentials. • All the optical properties of CsPb(I1-xBrx)3 were investigated using PBE-GGA and mBJ-GGA potentials in details. [ABSTRACT FROM AUTHOR]

The author discusses the availability of a fleet of nuclear power stations which are performing and have been life-extended to mitigate energy gap due to the resilience and dedication of nuclear professionals in Great Britain.