Search Results (41)

As buildings become more energy-efficient in cold climates, the unintended consequence of increased overheating risk during warmer seasons necessitates attention. In this context, there is an absence of research addressing the assessment of overheating risks in residential buildings in Ireland. This study assesses data from a sample of 1100 social housing units in Dublin, the majority of which have a Building Energy Rating (BER) of C, representing moderately insulated dwellings. Using indoor temperature data and outdoor climate reports for 2022, the research evaluates overheating risks based on both static and adaptive criteria in the living room zone of dwellings. The static methods used include the Chartered Institution of Building Services Engineers (CIBSE) Guide A and the Passivhaus Institute standard, while adaptive methods follow CIBSE TM59. The findings reveal discrepancies in overheating risk assessments: overall, 4% surpass thresholds under CIBSE Guide A. In contrast, 41% of dwellings exceeded overheating thresholds under the Passivhaus standard during the May to September 2022. Adaptive criteria, however, indicated minimal overheating instances, at 0.4%. These results highlight how different assessment methodologies influence overheating risk conclusions. The impact of this study is two-fold. First it further strengthens existing literature which questions the appropriateness of static methods. Secondly, it shows that the risk of overheating in moderately insulated buildings in this sample set is minimal. Full article

With growing concerns over energy and heat-related mortality/morbidity rates, enhancing building performances is key to improving the health and well-being of building occupants while reducing CO₂ emissions, in line with the UK Government’s Net-Zero targets. This study investigates the impacts of different retrofitting scenarios on overheating risk and energy performance in social housing for current and future climate conditions. Dynamic thermal simulations were carried out using Design Summer Year (DSY) weather files in DesignBuilder software for selected case study buildings. Winter performance was analysed using the Predicted Mean Vote (PMV) index, while summer results were assessed according to the Chartered Institution of Building Services Engineers Technical Memorandum 59 (CIBSE TM59) guidelines. The findings revealed that bedrooms, especially those facing south, were at high risk of overheating. Factors such as building construction, the number of exposed surfaces, and window area influenced the risks. External wall insulation outperformed internal wall insulation in improving summer comfort. In the winter, Passivhaus standards with natural ventilation ensured thermal comfort across all zones, with a 41–53% reduction in heating energy consumption under current weather conditions. The risk of overheating and associated health issues significantly increased for the future weather scenarios. Further investigation into ventilation strategies, occupant behaviour, and passive design is required to mitigate overheating risks while reducing energy consumption in buildings. Full article

Regulatory demands for indoor air renewal in buildings entail high levels of energy consumption. This is the only way to provide minimum indoor air quality (IAQ) and avoid some common lesions and pathologies. In Passivhaus standard (PHS) houses, a heat recovery system is required between the indoor–outdoor air masses of the air renewal system. This configuration substantially reduces energy consumption. In addition, the obligation to reduce envelope air leakage below the n₅₀ value of 0.60 ACH usually allows for a decrease in the energy consumed to less than 15 kWh/m²y in winter, as required by the PHS. It is complex, however, to quantify the energy demands of a building, whether in the project phase or in the operational or use phase. The present study focuses on the application of the PHS in Spanish Mediterranean housing. The aim was to assess whether it is suitable to use heat recovery systems by quantifying the energy savings obtained, execution costs, infiltration air flow, ventilator power usage, and maintenance. To this end, we performed a study on an existing PHS house in Abrera (Barcelona, Spain). It was found that heat recovery systems are always cost-effective in cold climates such as that of Central Europe but are only profitable in Spanish Mediterranean houses when the system costs less than approximately EUR 2500. In this case, the investment is covered over a period of 9.4–12.8 years and over 14–18 years when the equipment costs more than EUR 3000. Annual savings range from EUR 184.44 to 254.33 in Abrera compared to EUR 904.99 to 934.82 in a city like Berlin, that is, a 400–500% increase in savings. Moreover, leakage air energy accounted for 13% to 15% of that of renewal air, −1.348 kWh/m²y and 2.276 kWh/m²y compared to 8.55 kWh/m²y and 17.31 kWh/m²y, respectively. Lastly, recovery system average efficiency or η_t performance—which is usually between 82% and 95%—did not play a relevant role in deciding whether the system should be installed or not. Full article

Passivhaus (PH) has gained global recognition for its energy-efficient features despite a 5% to 10% higher construction cost than traditional houses, especially within European countries. However, its adoption and popularity have not met the same fate in other countries like New Zealand. The higher upfront cost has been critical to the slow adoption of the PH movement in New Zealand. This study aimed to demystify the mist around the cost of PHs with a focus on the effects of drivers and barriers on their life cycle costs (LCCs). As such, a systematic literature review was conducted to provide a comprehensive understanding of the cost implications associated with PH. Using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) review method, we examined 71 past studies on PHs from 2005 to 2023. We found that the drivers of PHs include reduced heating demand, increased thermal comfort, and indoor air quality (IAQ). Research showed that the rising market for PHs is fueled by climate change, environmental awareness, innovative materials and technologies, individual commitment, improved regulations, pilot studies, research efforts, and governmental funding and initiatives. However, PHs face significant challenges such as increased complexity, advanced technology, higher initial investments compared to conventional and low-energy houses, national requirements, overheating, difficulties in affording the technologies, and a lack of options in the market. Despite the wealth of research on the economic aspects of PH, there is a lack of in-depth studies exploring the LCC of PHs focusing on cost commitments and benefits. Such studies are essential for assessing and optimising the cost-effectiveness of PH, considering different climates and regions, and comparing them with other low energy standards. The findings of our review provide a crucial focus for PH stakeholders in assessing the long-term financial viability of PH projects, thereby improving decision-making and facilitating effective planning for sustainable and cost-effective housing. Full article

To obtain the Passivhaus Certificate or Passivhaus Standard (PHS), requirements regarding building envelope air tightness must be met: according to the n₅₀ parameter, at a pressure of 50 Pa, air leakage must be below 0.6 air changes per hour (ACH). This condition is verified by following the blower door test protocol and is regulated by the ISO 9972 standard, or UNE-EN-13829. Some construction techniques make it easier to comply with these regulations, and in most cases, construction joints and material joints must be sealed in a complex way, both on façades and roofs and at ground contact points. Performing rigorous quality control of these processes during the construction phase allows achieving a value below 0.6 ACH and obtaining the PHS certification. Yet, the value can increase substantially with the passage of time: as windows and doors are used, opened, or closed; as envelope materials expand; with humidity; etc. This could result in significant energy consumption increases and losing the PHS when selling the house at a later point in time. It is therefore important to carefully supervise the quality of the construction and its execution. In this study, we focused on a house located in Sitges (Barcelona). The envelope air tightness quality was measured during four construction phases, together with the sealing of the joints and service ducts. The blower door test was performed in each phase, and the n₅₀ value obtained decreased each time. The execution costs of each phase were also determined, as were the investment amortisation rates based on the consequent annual energy demand reductions. Air infiltration dropped by 43.81%, with the final n₅₀ value resulting in 0.59 ACH. However, the execution costs—EUR 3827—were high compared to the energy savings made, and the investment amortisation period rose to a 15- to 30-year range. To conclude, these airtightness improvements are necessary in cold continental climates but are not applicable on the Spanish Mediterranean coast. Full article

In response to escalating energy demands and global warming concerns, the Passive House Standard has emerged as a solution in residential construction, aiming to drastically reduce energy consumption and operational costs primarily through high-performance building envelopes. While a considerable volume of the literature has focused on the Passivhaus Institute (PHI) standards, predominantly in European contexts, there is a gap in research on the Passive House Institute US (Phius) standards, particularly in North American climates. This study conducts a quantitative comparative analysis of two adjacent multifamily residential buildings in Central Pennsylvania, Climate Zone 5A—one built using conventional construction methods and the other following Passive House (PHIUS+ 2015) certification standards—to validate the energy efficiency improvements attributed to Passive House designs. A comparative analysis of the whole building energy use over two years reveals that the Passive House building consumes approximately 50% less energy than its conventional counterpart in terms of whole building energy use and the national median recommended benchmark metric defined by the Energy Star Portfolio Manager. These findings emphasize the potential for significant energy savings and greenhouse gas reductions in residential buildings, highlighting the necessity for policymakers and governments to incentivize the adoption of Passive House standards to achieve environmental sustainability and reduce energy costs for society. Full article

This study presents a detailed analysis of thermal comfort and energy consumption in a Passivhaus-certified apartment in Bolueta Tower, Bilbao, Spain, over a period of three years (2020–2022). Utilizing a comprehensive, long-term monitoring approach, the research investigates the effectiveness of the Passivhaus standard in achieving both energy efficiency and occupant comfort in a temperate climate. Using calibrated data loggers to record indoor temperature, humidity, and CO₂ levels were used alongside the collection of utility bills to assess energy consumption and thermal comfort, as well as IAQ, against several international standards. Significant issues with overheating were confirmed, in line with previous research. During the warmer months, indoor temperatures frequently exceeded the Passivhaus comfort threshold of 25 °C, reaching as high as 31.3 °C, particularly in the living room and bedroom. This resulted in discomfort during summer, with the percentage of hours above 25 °C reaching 23.21% in 2022. Nighttime temperatures often surpassed 24 °C, impacting sleep quality. Conversely, heating consumption was minimal, corroborating the building’s energy efficiency in colder months. The findings highlight a critical gap in the Passivhaus standard when applied in milder climates, where overheating becomes a significant issue. This study suggests the need for an integrated approach in sustainable building design, one that balances energy efficiency with adaptive strategies to mitigate overheating, such as improved natural ventilation and thermal mass. These insights contribute to the ongoing discourse on optimizing energy-efficient buildings for occupant comfort in various climatic conditions. Full article

Overheating in buildings is a growing challenge in temperate climates, even in those where the traditional design focus was on protecting from cold and winter energy savings. This paper addresses a collateral problem that arose during the study of overheating in a residential Passivhaus building in Bilbao, northern Spain. Specifically, the local climate of three laundry spaces was investigated, where high daytime and nighttime temperatures were recorded. An extensive monitoring campaign was carried out with different durations up to more than 21,000 h over four years, and the collected data were compared with outdoor climatic conditions. The results allowed for characterizing the thermal behavior of these semi-outdoor spaces and show the magnitude of the problem, quantifying it. Laundry spaces were confirmed to be hotter and dryer than the outdoor climate almost always. The mean average difference between the monitored rooms and the exterior was quantified to be around positive 5 °C during both daytime and nighttime. Extreme heat events were documented, with maximum temperatures above 50 °C and temperature differentials of up to 15.85 °C. In addition, this article comments on the impact of overheating these laundry spaces on the interior of the dwellings, pointing out the differences between the assumptions made during the design phase of the project and the observed or measured reality. Questions were raised about the possible implications of the peculiar performance of these semi-outdoor spaces on the mechanical heat recovery ventilation system (MHRV). The data presented in this article revealed and quantified a design flaw that went unnoticed by all agents involved in the planning, design, and construction of the 361-apartment project. The inability to predict the behavior of the studied spaces has had a negative impact on building performance during the summer months and has prevented the implementation of strategies that could have been beneficial in other periods. A thorough analysis of the thermal behavior of similar spaces becomes essential to prevent performance gaps in future projects and to inform adequate building modeling in the design stages. Full article

Recently, the climate and landfill crises have raised concerns in the UK as the country is struggling to meet the sustainability goal it set to achieve. One of the major reasons is due to the inadequate recycling rate of waste paper. Therefore, as an alternative solution to the issue, the aim of our research was to exploit the potential of waste paper as an insulating material to see whether it can be feasible to improve the recycling rate of waste paper in the country. Waste paper has already been in the construction industry for a while, and the use of cellulose insulation is a standard in the Passivhaus construction approach. The study examines cellulose’s performance as an insulation material and its potential to combat the climate crisis by creating four separate comparisons and calculations using Life-Cycle Assessment and Standard Assessment Procedures. The study will investigate the benefits and limitations of the material as well as a case study to justify the use of it. A pioneer project in the field is a retrofit and new-built building project—54–58 Akerman Road in London. It utilises cellulose fibre insulation as the main material for the new-built part. The study will use this project as a context to compare whether cellulose fibre insulation is the best solution for the project. Also, the study will compare cellulose insulation with other conventional insulation materials in a more general setting as well as with the traditional paper recycling approach, by providing an indication of the carbon footprint of the insulation, the energy resources involved and the amount of raw material. By conducting the study, we can know whether recycling waste paper into cellulose insulation is the best solution to the crisis we face. This research can guide the UK’s recycling and use of waste paper, reduce paper waste and energy consumption and improve the sustainability of building insulation materials. Full article

The ongoing climate change and policies around it are changing how we design and build homes to meet national carbon emission targets. Some countries such as Scotland are adopting higher-energy-efficient buildings as minimum requirements in the building regulations. While net zero homes might be more energy-efficient and emit fewer operational carbon emissions, we have yet to fully understand the influence on the indoor environment, particularly on indoor air quality (IAQ) and thermal comfort. This study compares the IAQ of three homes in Scotland with equal internal layouts and designs but different building fabrics. The homes represent the minimum Scottish building regulations (2015), the Passivhaus standard and the Scottish ‘Gold Standard’. Temperature, relative humidity, PM_2.5 and total volatile organic compounds (tVOC) were measured at five-minute intervals for seven months and compared to occupants’ subjective responses to the IAQ. All three homes had temperatures above the recommended thresholds for overheating. Measured hygrothermal conditions were within the ideal range 66.4% of the time in the Passivhaus, 56.4% in the Gold Standard home and 62.7% in the control home. Measured IAQ was better in homes with higher energy efficiency, particularly tVOC. For instance, indoor PM_2.5 in the Passivhaus were 78.0% of the time below the threshold, while in the standard home the figure was 51.5%, with a weak correlation with outdoor PM_2.5 (Passivhaus: B r_s = 0.167, K r_s = 0.306 and L r_s = 0.163 (p < 0.001); Gold: B r_s = −0.157, K r_s = 0.322 and L r_s = 0.340 (p < 0.001); Control: B r_s = −0.111, K r_s = 0.235 and L r_s = 0.235 (p < 0.001)). TVOCs in the Passivhaus were 81.3%, while in the control home they were 55.0%. While the results cannot be generalised, due to the small sample, this study has significant policy implications, particularly in Scotland, exhibiting the importance of IAQ in current building legislation and sustainable assessment methods. Full article

Retrofitting buildings to achieve improved levels of energy performance is a key strategy in the transition to a low-/net zero carbon future. In China, there has been an enormous growth in residential construction in recent decades in response to the country’s economic development and population growth. However, although these buildings are structurally solid and have long functional life spans, most have very poor thermal performance. Therefore, they would be very suitable for energy retrofitting. Because of the variety of retrofitting options, it is important to review the retrofit measures, regulations and possible outcomes to find effective, long-term solutions that strike a balance between the energy saved, the carbon emitted and the financial costs over a building’s lifetime. This paper reviews suitable retrofit measures for the hot summer–cold winter region of China, because this is an area with huge numbers of residential buildings that are suitable for energy retrofitting. The study explores the current conditions of targeted residential buildings, retrofit schemes, building regulations, and policy gaps towards achieving China’s 2060 carbon neutrality goal. The review indicates that current mandatory building energy regulations in this region are not ambitious enough to achieve a significantly lower carbon future, and one-step deep Passivhaus retrofit schemes are recommended to achieve decarbonization goals. Full article

On average, houses including those in the tropics are responsible for almost 39% of the global carbon emission caused by non-renewables, first and foremost by fuel. Looking at the worldwide map of residential buildings’ contribution compared with commercial, the worldwide national maximum of 33.5% CO₂ of housing is caused by residential buildings in Uzbekistan. In an overwhelming number of most countries, their values are significantly lower, due to comparably lower energy demand than commercial buildings and because affordable homes increasingly use small PV to cater for their own basic needs. However, with the rising temperature and a likewise growing imperative to cool homes from about 30 °C onwards basically by split-unit air conditioners, the residential houses’ portion of CO₂-emission might dramatically increase to survive such more common hot periods in the future. In combination with air conditioners needing some airtightness, the first purpose of this entry is to show that bv 2050 in tropical regions, there will be no alternative to relatively airtight houses if the temperatures rise at the present speed. This is one alternative to an uncontrollable and life-threatening migration of millions of people to cooler but still livable regions in 2050. To trigger necessary changes toward homes that can better avert the heat, using the method of qualitative comparative content analysis, passive houses (PH) have emerged as adaptations to the tropical climate. Therefore, the second purpose of this in-depth study with the perspective of social science, is to reveal a comparative closer qualitative look at the tropicalized PH-approach. It is probably the most civilized building energy-saving strategy on the planet and can systematically keep the threatening increasing heat outside. However, before utilizing the concept, herein need to investigate why PH-technology as a whole concept with all its modules discussed earlier has been very slow to “go South” into the tropical region (the original PH will be referred to as “PH1”). The reason is that some qualitative differences of the more affordable and more simplistic tropicalized “PH2” make it easier and more realistic to penetrate the market, without letting go meaningful R&D-insights of PH1. As a probably facilitating future solution, the result is the triple-tabled option to utilise more synergies between the usually closed PH1 and the more open and flexibly naturally ventilated PH2. Unlike the PH-platform, ZEMCH is a related concept which tries to cater specifically to the significantly growing market for lower-income homes to go for carbonless energy. The conclusion is that scaling for residential buildings as mass products using passive house technology in combination with ZEMCH could turn out to become an important topic. It comprises the question in how far low or no carbon affordable homes based on the PH-concept in combination with ZEMCH-applications also may come into play as standard and to help mother Earth’s struggle for survival. Full article

Governments throughout the EU and the UK face a persistent challenge of satisfying the continual growth in demand for housing and create zero carbon buildings. This paper presents a novel conceptual framework and empirical results to evaluate the potential for Structurally Insulated Panels (SIPs) to address this challenge. Firstly, we present a comprehensive analysis of the energy performance of a SIPs building in the UK to evaluate the potential for such technologies to satisfy the energy and carbon objectives. Using our unique data set we show that SIPs can exceed the necessary energy efficiency standards and reach Net Zero Carbon. Secondly, we introduce game theory as a novel conceptual framework to understand the incentives of the manufacturers of SIPs and UK/EU authorities. This enables us to identify potential sources of incentive conflict, which inhibit the diffusion of such technologies. We demonstrate that it benefits both parties to engage in medium investment, but the inferior under investment scenario can emerge if the UK/EU does not provide leadership and commitment to SIPs technologies. Regardless of the market design in terms of the timing of decisions, the maximum level of support by both the UK/EU and the SIPs manufacturers cannot be achieved. Full article

In the last decade, several European directives have been established to contribute to the 2020, 2030 and 2050 energy saving targets and impose energy efficiency requirements for new construction, existing buildings and building renovation operations. One of the ways to achieve said objectives is to rely on the most demanding energy efficiency labels existing in Europe, such as Passivhaus, and to implement similar concepts into the national energy regulations of European countries based on a high-performance thermal envelope (high insulation and high-performance windows), high airtightness and high-performance heat-recovery ventilation systems, and solar heat harvesting. This energy conservation concept has shown to be effective for houses with low-density occupation in cold climates, but may cause severe overheating problems in denser collective housing in temperate and hot climates with higher solar radiation. To assess this impact, five flats in three developments from different periods that range from no insulation at all to a nZEB, Passivhaus-certified high-rise are compared in this paper, using data from a monitoring campaign during the summer of 2020. The results show and quantify the strong impact the evolution of the energy saving regulatory trend has had on summer indoor comfort, which may in some cases lead to previously unnecessary air conditioning for cooling and, ultimately, be counterproductive towards the end goals of reducing energy consumption and greenhouse-effect gas emissions and mitigating climate change. Full article

There is growing concern that airtight and well-insulated buildings designed to limit heat loss in temperate and cold climates could unintentionally elevate the risk of overheating in summers. Existing literature primarily uses dynamic simulation to investigate this problem due to the difficulty of obtaining large-scale in-performance data. To address this gap, we undertake a meta-analysis of large-scale indoor air temperature data for 195 UK dwellings, as a study of performance in a temperate climate. Of these, 113 are baseline (i.e., typical existing dwellings) and the rest designed to the high-performance Passivhaus standard. Using both Passivhaus and the well-known CIBSE TM59 overheating standards, this study found that there were few overheated cases for any building type. However, the average summer nighttime temperature of Passivhaus bedrooms was 1.6 °C higher than baseline, with 20 out of 31 measured bedrooms exceeding the overheating criterion, and the average overheating hours constituting approximately 19% of the total summertime observation period. These findings suggest that bedrooms in highly insulated dwellings may pose an overheating risk although whole-dwelling overheating risk is low. Full article