Search results

The article's aim is to present user experiences with passive houses and zero‐energy buildings. The focus is on the interaction between the building and the users, specifically on how user interfaces, knowledge, and commitment influence the use of the building and the level of energy consumption awareness.

The study follows an explorative grounded theory approach. This approach generates insights that will be consolidated in follow‐up studies. Qualitative interviews with users of six buildings were conducted. Site inspections applying walk‐through method and other available information complement the data.

Users in general were satisfied with having a new energy efficient building. Several respondents were more concerned about the environment now than before. However, there were concerns about thermal comfort. Misuse or misunderstandings among users in some cases led to lower indoor comfort. New or dissatisfactory design solutions were also responsible for unsatisfactory indoor environmental quality.Practical implications – Specific topics that should be paid more attention to in the design and research on new energy efficient buildings: level of end‐user control and adaptability of the building; level of complexity of systems; the need for adequate information.

The open approach enabled occupants to influence the parameters of the evaluations. Most evaluations of zero‐energy buildings are not yet publicly accessible.

This paper aims to investigate the impact of heat recovery ventilators (HRVs) on the energy use and indoor radon in a one family detached house. Heat recovery ventilation systems, because of reducing ventilation loss through recovered exhaust air, can play a good role in the effectiveness of ventilation to reduce energy use. In addition HRVs can maintain pressure balance and outdoor ventilation rate at a required level to mitigate indoor radon level.

In this study, a multizone model of a detached house is developed in IDA Indoor Climate and Energy (IDA ICE 4.0). The model is validated using measurements regarding use of energy for heating, ventilation and whole energy use. The performance of the heat recovery ventilation system is examined with respect to radon mitigation and energy saving by measuring the radon concentration and analyzing the life cycle cost of a heat exchanger unit.

The results of the measurements and dynamic simulation showed that the heat recovery ventilation system could lead to 74 per cent energy savings of the ventilation loss, amounting to about 30 kWh m⁻² per year. Life cycle cost analysis used for assessing total costs and the result showed that using this system is quite cost‐effective and investment would payback during 12 years.

Limitations of this study generally refer to radon measurement and simulation because of radon complex behavior and its high fluctuations even during short periods of time.

Heat recovery ventilation systems with reducing radon concentration improve indoor air quality and decrease environmental problems with energy savings.

Using balanced heat recovery ventilation can have benefits from the viewpoint of environmental impacts and household economy.

Employment of a heat recovery unit to control indoor radon level is a new usage of this technology which along with energy savings can improve sustainable development.

The purpose of this paper is to describe the use of computational fluid dynamics (CFD) to simulate indoor radon distribution and ventilation effects. This technique was used to predict and visualize radon content and indoor air quality in a one‐family detached house in Stockholm. The effects of intake fans, exhaust fans and doors on radon concentration were investigated.

In this study a mechanically balanced ventilation system and a continuous radon monitor (CRM) were used to measure the indoor ventilation rate and radon levels. In a numerical approach, the FLUENT CFD package was used to simulate radon entry into the building and ventilation effects.

Results of the numerical study indicated that indoor pressure created by ventilation systems and infiltration through doors or windows have significant effects on indoor radon content. The location of vents was found to affect the indoor radon level and distribution.

It may be possible to improve any discrepancies found in this article by using a more refined representation of grids and certain boundary conditions, such as pressure and temperature differences between inside and outside and by considering some real situations in residential buildings and external situations.

From the viewpoints of indoor air quality (IAQ) and energy savings, ventilation has two opposing functions; on the positive side it enhances IAQ and the establishment of thermal comfort, and on the negative side it increases energy consumption. This paper describes the search for a solution to cope with this contradiction.

New Zealand’s historical housing stock comprises largely single-storey detached houses, characterised by poor winter comfort with high air infiltration. Challenges with affordability and land use are shifting New Zealand’s housing stock towards double-storey, conjoined medium-density housing (MDH). Reduced external surfaces in this typology should reduce winter heat loss and infiltration, improving winter comfort and health. New concerns arise, however, regarding summertime overheating and poor indoor air quality.

A field study was undertaken where temperature, humidity, airtightness, particulate matter (PM) and total volatile organic compounds (TVOC) were measured in two unoccupied, newly built double-storey, conjoined houses, for several weeks over summer.

The reduced surface area of this typology did not reduce infiltration and demonstrated significant periods of overheating. Internal PM concentrations generally exceeded outdoor concentrations but did not exceed annual average outdoor PM10 guidelines of 20 µg m-3. Infiltration factors (Finf) were closer to more traditional houses. TVOC readings varied widely, but frequently exceeded international guidelines.

The small sample limits the applications of conclusions more widely. Recommendations to investigate a wider sample in different locations with more detailed VOC analysis over all seasons are made.

Improvements to internal environments cannot be guaranteed by housing typology changes alone and must still involve thoughtful environmental design.

Housing typology changes may not improve internal living environments.

A move to the new MDH typology may not achieve expectations of airtightness and thermal improvement. New challenges arise from significant overheating and high TVOC levels, which may lead to new negative health effects.

Poor indoor air quality (IAQ) contributing to occupants’ health symptoms is a universal, typically ventilation-related, problem in schools. In cold climates, low-cost strategies to improve IAQ in a naturally ventilated school are rare since conventional methods, such as window opening, are often inappropriate. This paper aims to present an investigation of strategies to relieve health symptoms among school occupants in naturally ventilated school in Finland.

A case study approach is adopted to thoroughly investigate the process of generating the alternatives of ventilation redesign in a naturally ventilated school where there have been complaints of health symptoms. First, the potential sources of the occupants’ symptoms are identified. Then, the strategies aiming to reduce the symptoms are compared and evaluated.

In a naturally ventilated school, health symptoms that are significantly caused by insufficient ventilation can be potentially reduced by implementing a supply and exhaust ventilation system. Alternatively, it is possible to retain the natural ventilation with reduced number of occupants. The selected strategy would depend considerably on the desired number of users, the budget and the possibilities to combine the redesign of ventilation with other refurbishment actions. Furthermore, the risk of poorer indoor air caused by the refurbishment actions must also be addressed and considered.

This study may assist municipal authorities and school directors in decisions concerning improvement of classroom IAQ and elimination of building-related symptoms. This research provides economic aspects of alternative strategies and points out the risks related to major refurbishment actions.

Since this study presents a set of features related to indoor air that contribute to occupants’ health as well as matters to be considered when aiming to decrease occupants’ symptoms, it may be of assistance to municipal authorities and practitioners in providing a healthier indoor environment for pupils and teachers.

Ventilation is driven by weather conditions, occupant actions and mechanical ventilation, and so can be highly variable. This paper reports on the development of two analysis algorithms designed to facilitate investigation of ventilation in occupied homes over time.

These algorithms facilitate application of the CO₂ concentration decay tracer gas technique. The first algorithm identifies occupied periods. The second identifies periods of decaying CO₂ concentration which can be assumed to meet the assumptions required for analysis.

The algorithms were successfully applied in four occupied dwellings, giving over 100 ventilation measurements during a six-month period for three flats. The specific implementation of the decay identification algorithm had important ramifications for the ventilation rates measured, highlighting the importance of interrogating the way that appropriate periods for analysis are identified.

The analysis algorithms provide robust, reliable and repeatable identification of CO₂ decay periods appropriate for ventilation rate analysis. The algorithms were coded in Python, and these have been made available via GitHub. As well as supporting future CO₂ tracer gas experiments, the algorithms could be adapted to different purposes, including the use of other tracer gases or exploring occupant exposure to indoor air pollution.

Empirical investigations of ventilation in occupied dwellings rarely aim to investigate the variability of ventilation. This paper reports on analysis methods which can be used to address this gap in the empirical evidence.

If the building control system is to deliver housing which achieves major reductions in carbon dioxide emissions, it is important to ensure not only that energy efficiency standards are set at an appropriate level but also that the specification of standards takes into account realised performance. It is argued in this paper that, in many cases, there is a large gap between notional performance, as defined by the calculation methods embodied in the Building Regulations, and performance achieved in practice. Although it is accepted that some variation in performance is to be expected, there are a number of areas where closer attention to the methods used to estimate thermal performance, and the inclusion of hitherto unregulated aspects, could help to achieve a much closer match between what is expected and what is achieved. In particular, the paper discusses ways in which the Regulations could be improved so that the impact of thermal bridging, construction quality, window performance and airtightness are more closely controlled.

Millions of properties have suspended timber ground floors globally, with around ten million in the UK alone. However, it is unknown what the floor void conditions are, nor the effect of insulating such floors. Upgrading floors changes the void conditions, which might increase or decrease moisture build-up and mould and fungal growth. The purpose of this paper is to provide a review of the current global evidence and present the results of in situ monitoring of 15 UK floor voids.

An extensive literature review on the moisture behaviour in both uninsulated and insulated suspended timber crawl spaces is supplemented with primary data of a monitoring campaign during different periods between 2012 and 2015. Air temperature and relative humidity sensors were placed in different floor void locations. Where possible, crawl spaces were visually inspected.

Comparison of void conditions to mould growth thresholds highlights that a large number of monitored floor voids might exceed the critical ranges for mould growth, leading to potential occupant health impacts if mould spores transfer into living spaces above. A direct comparison could not be made between insulated and uninsulated floors in the sample due to non-random sampling and because the insulated floors included historically damp floors. The study also highlighted that long-term monitoring over all seasons and high-resolution monitoring and inspection are required; conditions in one location are not representative of conditions in other locations.

This study presents the largest UK sample of monitored floors, evaluated using a review of current evidence and comparison with literature thresholds.

The purpose of this paper is to present defects reported by cooperative owners, and to determine the relationship between building characteristics, developer’s/contractor’s company size and defect type.

The analysis is based on defects reported by board members of cooperatives in Sweden through a survey questionnaire. The 1,563 questionnaires were posted by regular mail to the boards of cooperatives for buildings. The current research presents results from analysis of responses from 394 regular residential projects constructed between 2006 and 2013. The responses represent owners’ experience from a total 1,107 buildings.

Findings presented in this study indicate that building quality might be one of the factors contributing to the energy gap. The analysis indicates that the most severe problems reported by cooperatives are issues related to building envelope, particularly shortcomings in the function of windows, issues related to the function of the balcony and cracks in the facade and leakage caused by rain water. The results show that the building quality differs depending on developers’ size, measured by number of employees. The authors have also found a significant relationship between reported defects and location expressed by size of the city/municipality.

The discussion on newly constructed residential buildings has been dominated by the perspective of professionals (inspectors) and contractors (or developers) rather than of the owners/users themselves. This study presents findings from the owners’ perspective, thus contributing the owners’ viewpoint to the debate on building quality.

The purpose of this paper is to demonstrate the relevance and use of the concept “reverse salient” in ambitious infrastructural change. Thomas Hughes, in his seminal study of socio-technical system building, observed that the elimination of “reverse salients”, i.e. subsystems that because of their limited performance hold back further development, was a central driver for creativity and innovation. It is argued that in sustainable infrastructural transformations, however, reverse salients that resist change are more often neglected than addressed.

Higher education institution campuses combine laboratory-like conditions and sufficient internal complexity to be used as test-beds for ambitious sustainable change in the built environment. In this article, a neglected barrier to the transformation of a small campus into a zero emission campus is revealed, described and addressed.

In terms of substantive findings, first, it is demonstrated how parts of infrastructures that – often for good reasons – have been neglected in efforts to reduce climate impacts can be identified with the help of a historical exploration of the site and through close collaboration with local facilities managers. Second, a temporary low-tech intervention is presented that addressed the critical problems related to these “reverse salients”.

The limitations of a case study approach apply to this study. Particular caution has to be exercised in terms of generalisation. Moreover, the intervention would benefit greatly from stricter control and additional iterations of the intervention which have not yet been performed.

In addition to technology-focussed, top-down initiatives, which often struggle with actually reaching their ambitious goals in routine operation, neglected parts of campuses can contribute greatly to energy and emissions reductions. Moreover, it is demonstrated that and how local technical personnel has an important part to play in infrastructural transformations.

Concepts developed in the study of socio-technical system building have not yet been applied in the study and practice of sustainable infrastructural transformation. Their contribution is demonstrated. Moreover, living labs are notoriously difficult to evaluate. In this case study, processes and effects of an innovative living lab intervention are described and analysed. This enables a better understanding of restrictions and possibilities of experimenting in real-life settings.