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Brazil faces a housing deficit of more than 5.5 million units and nearly 11 million existing homes present inadequate living conditions. In response, the Brazilian government launched in 2009 a mass social housing programme with a target of delivering 24 million new units for low-income households by 2022. Their standardised design is relatively cheap to build but does not take into account climatic conditions, thermal comfort and energy efficiency. This could result in poor performance and uncomfortable indoor environments that could impact of the occupier's health and lead to the unnecessary use of energy-hungry space conditioning systems. Given the scale of this programme, the potential impact on Brazil's already debilitated socio-economic and environmental balance is very substantial. In this work, the authors have deployed sensitivity analysis to explore a variety of envelope combinations through dynamic building simulation for three southern Brazilian cities, Curitiba, Sao Paulo and Porto Alegre, aiming to achieve better than the typical performance. Thermal transmittance properties and air permeability rates were tested from the most common construction characteristics in Brazil to some of the highest levels of fabric energy efficiency. These combinations were also analysed in terms of their cost-effectiveness. The results suggested that optimised envelopes could improve thermal comfort by up to 97% in comparison to a typical envelope, but also cost nearly 50% more. Other envelope combinations investigated were shown to be more cost-effective with a significant increase of thermal comfort levels and were therefore considered to be a more adequate solution for the context. [ABSTRACT FROM AUTHOR]

Evidence suggests that many UK dwellings are subjected to overheating or will be at some point in the future. Dwellings built using modern methods of construction may have a higher overheating risk due to the low levels of thermal mass associated with most of these methods. The Nottingham HOUSE, a prefabricated timber modular building designed to zero-carbon and Passivhaus standards, was examined in terms of overheating occurrence. The ability of a high-density fibreboard and phase change materials to provide additional levels of thermal mass was examined with the results suggesting that these can help regulate internal temperatures with the benefit of being easy to integrate. [ABSTRACT FROM AUTHOR]

The ever-increasing energy demand of the residential sector has required the adoption of tighter energy standards, aiming for high energy efficiency in dwellings. In Brazil, 24 million new residential buildings are planned to be delivered by 2022 through social housing programs, which could greatly impact on the country's energy consumption. In an attempt to minimize this impact, the Brazilian Labelling Scheme for Residential Buildings (RTQ-R label) was launched in 2010 as a voluntary standard for the evaluation of housing energy efficiency. The RTQ-R label focuses on building fabric and hot water systems performances, and generates a score based on the building's energy efficiency levels. The Passivhaus standard, developed in Germany, is one of the most stringent standards and is also the fastest growing energy performance standard in the world with more than 30,000 buildings certified to date. It also focuses on building fabric but establishes a maximum energy consumption target. In this work, the authors developed a comparative review of the RTQ-R label and the Passivhaus standard as means to inform a broader debate about building codes in the context of the current calls by governments for increased energy efficiency. The findings highlighted the different nature of the standards' requirements and targets adopted, and the benefits and constraints of both. [ABSTRACT FROM AUTHOR]

Abstract: The work forms part of the CALEBRE project (2008–2013), the aim of which was to investigate a suite of technologies and staged approaches for retrofit upgrades for ‘hard-to-treat’ solid/thin cavity masonry-walled UK domestic buildings that would i) reduce operational energy demand/carbon emissions, and ii) be acceptable and appealing to the building occupants. The E.ON Retrofit Research House (Nottingham, UK) was used as an instrumented test platform as part of this study. The retrofitting phases (and technologies) have been used as the basis for the modelling methodology in this paper, together with the corresponding envelope assemblies, material properties, climate, and internal load parameters. The approach to retrofit was to increase air tightness (reduce ACH), decrease static U-values of the external envelope (wall, floor and glazing), and upgrade heating system efficiency. This was complemented by a combination of options that included a whole-building system of mechanical ventilation with heat recovery (MVHR). These interventions were analysed alongside simulated passive buffering of variations in indoor air psychrometric conditions using conventional (clay, timber) and advanced (mesoporous silica) wall surface treatments. Each retrofit scenario was modelled using an energetic hygrothermics building performance simulation (BPS) approach to determine the combined effects of retrofit packages on indoor air psychrometric conditions, external envelope (dynamic) heat transfer, operational energy efficiency, occupant comfort, and mould growth potential. It is proposed that this approach can provide the basis for an intelligent risk management strategy to inform both the design and deployment of retrofit upgrade packages intended for residential buildings. [Copyright &y& Elsevier]

Abstract: Half of humanity now lives in cities and the cities of the world continue to expand. However, inappropriate design of buildings combined with heat island conditions in dense urban areas and the effects of climate change may result in unsuitable accommodation, which is inherently unsustainable. An underlying problem in the long term housing supply has led to demand not being met for many years. The British government therefore announced that it is committed to increase the rate of house-building and support the use of Modern Methods of Construction as a possible solution. Simultaneously, in an attempt to tackle climate change, an ambitious target has been set for all new houses to meet net zero carbon dioxide emissions from 2016. The Mark Group Research House, a super insulated steel frame home, was designed to test MMC solutions and innovative technologies, and to achieve ‘zero carbon’ without compromising user''s comfort. A computer model was used to investigate the house''s potential for overheating in today''s weather as well as in future climate scenarios. The simulations have found that generally the house is comfortable but, despite the addition of mitigating strategies, there is a risk of overheating which is aggravated in future scenarios. [Copyright &y& Elsevier]

Building airtightness is a critical aspect for energy-efficient buildings as the energy performance of a building can be significantly reduced by poor airtightness. The Pulse technique has been regarded as a promising technology, measuring building airtightness at a low pressure of 4 Pa. However, due to the rapid dynamic nature of the test, a frequently raised question concerns the uniformity of the pressure distribution across the internal space of the test building during the air pulse release. In order to investigate this point, experimental work was conducted in a five-bedroom dwelling. All the tests were conducted at wind speeds less than 0.45 m/s to minimise the wind impact on the indoor pressure. The results show a pressure difference within the building during the Pulse test does exist, but considering the accuracy of differential pressure transducers, the deviation is not significant. In addition, a subtle variation is noted when the Pulse test was conducted at different locations on the ground floor, which may also be caused by variations in the environmental conditions. In terms of the airtightness measurement, a good overall agreement was found between the Pulse technique and the conventional blower door fan pressurisation method, which indirectly verified the uniformity of the indoor pressure distribution during both tests. Moreover, the error analysis demonstrated the validity of the measurement results for the two test methods in this study. • Pulse tests were performed in a large dwelling to represent a worst-case scenario. • Both the Pulse and blower door tests showed a uniform indoor pressure distribution. • The two methods have a good overall agreement on the airtightness measurement. • The pulse release location had a minor impact on the airtightness measurement. • The error analysis demonstrated the validity of the test results for both methods. [ABSTRACT FROM AUTHOR]

The UK building stock, being amongst the oldest in the developed world, is also one of the least energy efficient and accounts for approximately 45% of UK carbon emission. Energy use from housing alone was responsible for 13% of total UK carbon dioxide and greenhouse gas emissions in 2015. Therefore, achieving the national target of an 80% reduction in carbon emissions by 2050 against 1990 baseline conditions is highly dependent on the reduction of energy consumption in dwellings. The complexity of the problem of retro-fitting energy saving measures in the extensive and diverse aging housing stock is further compounded due to the number of ‘hard to treat’ properties that comprise over 40% of homes in the UK. In this article, the authors present an evaluation of the theoretical and experimental performances of a novel prototype external wall insulation system, developed to improve energy efficiency in ‘hard to treat’ housing. The system was designed to be primarily used to retrofit social housing, which comprises up to 18% of the current UK housing stock. A thorough testing regime was undertaken to test the suitability and effectiveness of the new product in the most common social housing construction typologies. This included: an investigation of the theoretical thermal performance of the prototype product through steady state modelling, a laboratory based prototype test, an analysis of empirical data collected from a cross section of social housing properties in Nottinghamshire, UK used to inform whole house dynamic modelling, and the development of dynamic simulations to assess the energy and carbon reduction impacts of the new product. The theoretical modelling suggested that the integration of the system resulted in thermal performance improvements for all construction types with space heating demand reduced by up to 42%. The results of the whole house dynamic modelling assessment also suggested that the addition of the system resulted in a reduction of heating energy demand of up to 49%. The prototyping testing shown that the system is easy to install requirement minimum building skills. The findings suggest that the new product not only meets the performance of existing external wall insulation systems, but also provides unique selling points with respect to easy installation and non-reliance on weather conditions. The project finished with a pilot study when one house was retrofitted using the novel product. [ABSTRACT FROM AUTHOR]