Leeds Sustainability Institute projects

Behaviour change post occupancy evaluation case studies

Public perceptions of hydrogen are currently only guessed at by the research and industry community. As a result, we have no idea about how communities and individuals would respond to the prospect of a 100% hydrogen conversion, which could change the look and feel of daily core practices e.g. cooking and heating.  As part of the H21 NIC project a programme of social science research is being undertaken by Leeds Beckett University. This research will ensure that some of the issues regarding perceptions of hydrogen are confronted and new knowledge generated. The research aims are as follows:
Generate insight into baseline public perceptions of the safety of hydrogen and other energy technologies/vectors including how they vary by a range of socio-demographic and geographic variables.

Generate insight into how people respond to the possibility of using 100% hydrogen in the three-key, gas-fuelled social practices (heating, cooking, travelling), including how they vary by a range of socio-demographic and geographic variables.
Understand how public perception of the safety of hydrogen evolves across the range of socio-demographic and geographic variables when considering the H21 NIC evidence.

Build a hydrogen research network of social scientists across the UK who may then become involved in the delivery of the proposed research activity or who may play advisory roles in the development of a body of research, data and expertise around the opportunities and challenges of hydrogen.

BPE of Prototype Low Carbon Dwellings

The Temple Avenue Project, funded by the Joseph Rowntree Housing Trust, outlines the initial evaluation of the design, construction and performance of two prototype low carbon dwellings and helps establish the extent to which an existing 1930s masonry house can be renovated so as to achieve a level of performance commensurate with the advanced energy and carbon standard of the prototype new dwellings. The two prototype dwellings contained some technological innovation and were constructed between July and December 2009. One prototype was constructed using thin-joint masonry construction and another using a structural insulated panel (SIPs) build system. The concurrent renovation works to an adjacent existing dwelling explored the impact of two standards of renovation, one reflecting the standard fabric measures that are currently considered to be cost effective and one reflecting the more challenging requirements of an 80% emissions reduction and incurring greater capital costs.

Research Outputs

Leeds was designated a core city for trialling the Government’s Green Deal domestic energy efficiency policy. Leeds Beckett University undertook a monitoring and testing program on 65 dwellings to investigate the effectiveness of the insulation measures installed and to understand any underperformance. This report outlines the findings from a series of investigations including; surveys, air tightness tests, co heating tests, in situ U-value tests, hygrothermal and thermal bridging modelling, in use monitoring and occupant interviews. The surveys revealed that the ‘whole house approach’ to retrofit was, more often, missing, and quality assurance around insulation detailing was regularly absent, leading to avoidable errors and potentially embedding problems in the installations. Furthermore, moisture issues were, in the majority of instances, over-looked or made worse despite over half the sample having some form of damp. Despite this, energy savings were observed and the appearance of the dwellings were improved, thus apparent satisfaction was generally high, even though the installs were imperfect and moisture problems were introduced.

Research Outputs

  • Gorse, C.A.,& Glew, D., Johnston, D., Fylan, F., Miles-Shenton, D., Smith, M., Brooke-Peat, M., Farmer, D., Stafford, A., Fletcher, M. and Thomas, F. (2017) Core cities Green Deal monitoring project – Leeds, 2017, Department of Energy and Climate Change.
  • Fylan, F., Glew, D., Smith, M., Johnston, D., Brooke-Peat, M., Miles-Shenton, D., Fletcher, M., Aloise-Young, P. and Gorse C. (2016) Reflections on retrofits: Overcoming barriers to energy efficiency among the fuel poor in the UK, Energy Research and Social Science, 190-198
  • Hardy A, Glew D, Gorse C, Fletcher M, (2018), Validating solid wall insulation retrofits with in-use data, Energy and Buildings, 165, 200-205
  • Glew, D.W., Smith, M., Miles-Shenton, D. and Gorse, C. (2017) Assessing the quality of retrofits in solid wall dwellings, International Journal of Building Pathology and Adaptation, 35 (5), 501-518

Evaluating the performance of novel Internal Wall Insulation

This report presents the preliminary findings from before and after building performance evaluation (BPE) field trials undertaken to measure the impact of 6 TIWI and 1 conventional IWI retrofits. Their impact on thermal bridging and hygrothermal models identified how they affected moisture risk. Dynamic simulation models predicted the energy demand reductions to evaluate potential carbon and fuel bill savings. Coheating test measured the reduction in the heat transfer coefficient (HTC) measured in W/K, which describes the holistic impact on the home’s heating demand.  In addition, blower door tests and heat flux measurements quantified the difference that the retrofits had on infiltration (uncontrolled air leakage) and fabric heat loss, i.e. wall U value measured in W/m²K, respectively. Appraisal of the installation costs and how the TIWI products could overcome installation barriers was undertaken, supported by surveys in 100 homes to identify insulation and dwelling characteristics that affected costs or risks, such as requirements to replace plumbing, boilers & radiators, apply decoration or repair damp walls.

Research Outputs

This project is currently in progress, if you would like any more information, please contact us.

Nationwide BPE investigations into Low Carbon Homes

In 2011, the Technology Strategy Board (now Innovate UK) launched the £8million Building Performance Evaluation (BPE) Programme. An overarching aim of the BPE programme was to assemble comparable data and knowledge about a large number of buildings to enable analysis across the body of case study information, leading to generic findings conclusions and learning for the sector as a whole. As part of this Programme, the Centre for the Built Environment (CeBE) were successful in securing over £500,000 of external funding to undertake six post construction and early occupation studies (25% of all of the domestic projects awarded under the Technology Strategy Board BPE Programme) and two in-use performance and post occupancy evaluation studies. Additionally, all participants involved in the wider BPEP were required to adhere to standardised BPE practices based on the Leeds Beckett University Coheating Text Protocol.

Research outputs

  • Gentoo Passivhaus Racecourse Development, Sunderland
    Type of study – Post construction and early occupation.
  • Gentoo Passivhaus Racecourse Development
    Type of study – In-use performance and post occupancy evaluation.
  • Dormary Court, York
    Type of study – Post construction and early occupation.
  • Dormary Court, York
    Type of study – In-use performance and post occupancy evaluation.
  • Lancaster Cohousing Development, Lancaster
    Type of study – Post construction and early occupation.
  • Community in a Cube (CIAC), Riverside One, Middlesborough
    Type of study – Post construction and early occupation.
  • Derwenthorpe, York
    Type of study – Post construction and early occupation.
  • Lea Field Court, York
    Type of study – Post construction and early occupation.
  • Fletcher MJ; Johnston DK; Glew D; Parker J (2017), An empirical evaluation of temporal overheating in an assisted living Passivhaus dwelling in the UK. Building and Environment, 121, Pages 106-118
    https://doi.org/10.1016/j.buildenv.2017.05.024
  • JOHNSTON, D. and SIDDALL, M. (2016) The Building Fabric Thermal Performance of Passivhaus Dwellings—Does It Do What it Says on the Tin? Sustainability, 8(1), 97; DOI:10.3390/su8010097.
  • JOHNSTON, D. and STAFFORD, A. (2016) Estimating the Background Ventilation Rates in New-Build UK Dwellings – is n50/20 appropriate? Indoor and Built Environment. Published online before print January 28, 2016, DOI: 10.1177/1420326X15626234.
  • JOHNSTON, D. MILES-SHENTON, D.FARMER, D. and BROOKE-PEAT, M. (2015) Post Construction Thermal Testing: Some Recent Measurements. Engineering Sustainability. Volume 168, Issue 3, June 2015, pp. 131-139. DOI: 10.1680/ensu.14.00048.
  • JOHNSTON, D. MILES-SHENTON, D. and FARMER, D. (2015) Quantifying the Domestic Building Fabric ‘Performance Gap’. Building Services Engineering Research & Technology (BSER&T). Volume 36, No.5, September 2015, pp.614–627. DOI:10.1177/014362441557034.
  • JOHNSTON, D. FARMER, D. BROOKE-PEAT, M. and MILES-SHENTON, D. (2014) Bridging the Domestic Building Fabric Performance Gap. Building Research & Information. Volume 44, Issue 2, pp.147-159. DOI:10.1080/09613218.2014.979093.

Evaluating the success of MVHR retrofits

The aim of this project was to assess the effectiveness of the whole house mechanical ventilation and heat recovery (MVHR) systems within the existing UK housing stock.  This was investigated via field trials into homes where MVHR was installed as part of a comprehensive energy efficiency and environmental improvement package. Evaluations were made in terms of energy use, thermal comfort, internal air quality and acceptability to tenants.

Research outputs

  • Lowe R and Johnston D (1997) A Field Trial of Mechanical Ventilation with Heat Recovery in Local Authority, Low Rise Housing.

Data analysis, modelling and simulation case studies

Investing the potential for green spaces to reduce the heat island effect in the UK and China

This project is funded by Innovate UK, in collaboration with VRM Tech, the University of Hull, and academic partners in Shanghai. The Urban Heat Island (UHI) effect, in which cities become warmer than their surrounding green space, is a increasing problem. Major cities such and London and Shanghai are particularly suffering from the UHI effect and, during hot periods, these cities experience increased energy consumption, high levels of pollutants and negative consequences on resident health.

The principal cause of the UHI effect is the replacing of green space with buildings, roads, tarmac etc. A potential mitigating intervention is therefore to build green spaces and/or trees within your city. However, where and how to place your green assets is a complex problem. A park surrounded by skyscrapers may have less effect than one surrounding by low-level buildings. In addition, building trees in certain areas may cause them to be under stress and release VOCs, which could counter-productively increase levels of pollution. The GIAUrban project is aimed at understanding the effect that parks and trees have on the local environment. This will be achieved via a combination of open data, and data obtained by a bespoke drone-mounted hyperspectral camera. The knowledge gained during this project will be used by VRMTech to create a commercial tool that allows planners to see the effect building green spaces is likely to have.

Investigating the potential for flexibility to solve energy problems of the future

Leeds Sustainability Institute's building performance group are taking a lead on the International Energy Institutes Annex 67 project, Energy Flexible Buildings project, with more than twenty participants from across Europe and further afield. The project has commenced its preparatory year, with substantial input from our university, looking into how buildings can contribute and interact with energy networks.

Research outputs

For more information about this project please contact us.

Validating remote ways to measure thermal performance

SMETER Technologies comprise algorithms that calculate the Heat Transfer Coefficient (HTC) in combination with a product that is installed in the home to measure the parameters required by those algorithms. The feasibility phase will provide Competition Participants with data and advice to develop their algorithms and products and the results will be assessed to help decide which SMETER Technologies go through to the Field Trial. The Field Trial will evaluate the accuracy of the developed SMETER Technologies and their user acceptability. Our team brings together the UK’s leaders in this area of research, and is ideally placed to deliver an academically rigorous evaluation, as well as to provide the robust methods, models and data sets required to enable others to innovate in this area for many years to come.

Research outputs

For more information about this project please contact us.

Identifying errors in EPCs

Funded was provided by the Economic and Social Research Council via the Consumer Data Research Centre. Energy Performance Certificates (EPCs) give people an idea of how energy efficiency their homes are, but EPCs are notoriously unreliable and full of errors. This project identifies EPCs which are likely incorrect allowing them to be removed from any analysis. The project found that a large number (up to 62%) of EPCs contain at least one major error, calling into question how useful they are as a measure of energy efficiency in their current form. Furthermore, the errors found in each region of the UK varies considerably, with London containing the most.

Research outputs

Challenging the equity of UK Energy Price Caps

In 2017, the British Government imposed a cap on prepayment energy prices in an attempt to combat fuel poverty. The maximum amounts allowed in the price caps were based on national averages, which can ignore some of the finer detail in the data. In this work, we used smart-meter data to see if any demographics are not receiving the full benefit of the price caps. The findings suggest that many economy 7 customers are not behaving typically, and may find themselves still struggling under the current price caps.

Research outputs

  • Hardy, A., Glew, D. and Gorse, C. (2018) Assessing the equity and effectiveness of the GB energy price caps using smart meter data, Energy Policy, 127, 179-185

Evaluation of Heat Pump Performance

Harrogate Borough Council has placed itself in the forefront of sustainable development of existing social housing stock by installing Ground Source Heat Pump technology in around 80 properties, with plans for further installations in the future. Ground Source Heat Pumps extract heat at relatively low temperatures from an external ground loop or borehole, and transfer this heat to water in a heating system, raising its temperature sufficiently to provide both space heating and domestic hot water. The system can be supplemented by a small amount of electrical resistance heating to cover any shortfall and to raise domestic hot water temperatures to high levels for short periods, e.g. during pasteurization cycles. Some monitoring of heat pump operation and performance has already taken place and some (limited) contextual information (building type, occupancy, maintenance etc.) is also available. This data has been gathered by Harrogate Borough Council as part of normal operations, without, as yet, any attempt at a systematic analysis of heat pump performance across the Borough. This project aims to systematize existing data, using the conclusions drawn to inform the scope and methodology of future data collection. As far as is practicable at this stage it will assess the energy cost and CO2 savings achieved by the systems, and will develop in-depth case studies of a small number of selected installations via collection of additional data.

Research Outputs

Maximising the benefits of Smart Meters

A five-year project funded by the Engineering and Physical Sciences Research Council (EPSRC) to develop a Smart Energy Research Lab (SERL) to provide vital access to energy data for the UK research community. The project is led by University College London (UCL), and is being undertake in collaboration with the University of Essex (UK Data Archive), the University of Edinburgh, Cardiff University, Loughborough University, the University of Southampton, The Energy Saving Trust and Leeds Beckett University.

Research outputs

For more information contact us or visit UCL through the link below.

Identifying energy efficiency improvements in supermarkets

Energy use and management in supermarkets represents a challenge as well as an opportunity. Improvements have the potential to benefit companies and consumers, and to contribute to the achievement of UK carbon reduction targets. This research project has the aim of improving energy efficiency in supermarkets using data visualisation tools. Funding was provided by Innovate and partners were; ASDA, who provided the data and case studies, Cybula, who developed the software, REMS and the Leeds Sustainability Institute (LSI), based at Leeds Beckett University. The project identified that It is recommended that visualisation tools should only be used in stores where there is high confidence around the quality and quantity of available data and a data capture pro forma has been develop to inform this. Shop floor area is conventionally the preferred method of normalising energy data to rank store performance. This was found to be acceptable and other minor variables were discovered to be relatively unimportant. However, using volume to normalise gas and HVAC energy use; and using chilled floor area when normalising refrigeration energy provided the best normalisation. Two approaches were used to predict a store’s ‘normal’ performance. The first simply used data to determine the mathematical correlation between energy use and energy demand. This produced a somewhat useful model for gas use and refrigeration energy use that could be incorporated into a visualisation tool, though HVAC energy use displayed much weaker correlation. The second approach used calibrated simplified dynamic simulation models to create baseline models of stores to compare stores as well assessing changes in energy caused by varying inputs such as same ceiling heights.

Research outputs

For more information about this project please contact us.

Identifying the causes of damp to protect vulnerable tenants and inform council interventions

As part of the project investigating the condition and damp issues in Leeds City Council owned homes, Leeds Sustainability Institute at Leeds Beckett University were commissioned to undertake a series of quantitative and qualitative research exercises. These were: airtightness measurement of dwellings, thermographic survey of dwellings, occupant interviews, and analysis of in-use internal environment data. Overall, the airtightness of dwellings in the research sample is not a major concern when considering their age and material condition. The key consideration, however, is that the values presented are for uncontrolled air movement aggregated across the whole dwelling. It is likely that air exchange in not occurring in a consistent way, with some areas potentially over-ventilating (e.g. windows, gaps and cracks) and some under-ventilating (e.g. wet rooms). It is for this reason that it is necessary to undertake a thermographic survey alongside the airtightness test when the dwelling is depressurised. The thermal surveys identified several commonly occurring issues with the building fabric, which may contribute to the formation of damp and mould. One barrier to tenants taking preventative action was a lack of capability due to faulty or non-existent mechanical ventilation systems. Although aware of risk, occupants reported very little guidance for damp prevention, suggesting a lack of knowledge towards both the cause and prevention of damp. Damp prevention guidance may therefore be effective in reducing damp occurrence.

Research outputs

For more information about this project please contact us.

New build performance gap case studies

Implementing advanced energy standards for housing

Stamford Brook is a development of around 700 cavity masonry dwellings that was being constructed on part of the National Trust’s Dunham Massey Estate near Altrincham in Cheshire. Construction on the site commenced in 2004 and continued until around 2009/2010. The development was carried out under a partnership agreement between the land owner, the National Trust, and the two developers Redrow and Bryant Homes. The development partners were also participating in a “Partners in Innovation” (PII) project with the Centre for the Built Environment at Leeds Metropolitan University that has investigated various aspects of the design and construction processes. The Stamford Brook PII project is a unique record of the achievements, successes, failures, problems and solutions that can occur during the implementation of an advanced energy standard on a large scale housing development. Using participatory action research methodologies, the research project team has followed the progress of the development from initial discussions on the energy standard and environmental standard, through the detailed design process, observation of construction of the dwellings, performance testing of completed buildings and monitoring of occupied houses.

Research outputs

BPE of Prototype Low Carbon Dwellings

The Temple Avenue Project, funded by the Joseph Rowntree Housing Trust, outlines the initial evaluation of the design, construction and performance of two prototype low carbon dwellings and helps establish the extent to which an existing 1930s masonry house can be renovated so as to achieve a level of performance commensurate with the advanced energy and carbon standard of the prototype new dwellings. The two prototype dwellings contained some technological innovation and were constructed between July and December 2009. One prototype was constructed using thin-joint masonry construction and another using a structural insulated panel (SIPs) build system. The concurrent renovation works to an adjacent existing dwelling explored the impact of two standards of renovation, one reflecting the standard fabric measures that are currently considered to be cost effective and one reflecting the more challenging requirements of an 80% emissions reduction and incurring greater capital costs.

Research Outputs

BPE of sustainable housing development

This project set out to provide a robust approach to the evaluation and monitoring of the Elm Tree Mews sustainable housing development in York. The development is being undertaken by the Joseph Rowntree Housing Trust, supported by the Joseph Rowntree Foundation and is intended to address the issues involved in creating low carbon, sustainable housing. It is anticipated that the lessons learned will be fed back to the industry at large. The research project consisted of a retrospective evaluation of the design and construction process, performance measurements of the dwellings as constructed (compared with design expectations) and the monitoring of energy and other performance characteristics of the dwellings in use.

Research outputs

Nationwide BPE investigations into Low Carbon Homes

In 2011, the Technology Strategy Board (now Innovate UK) launched the £8million Building Performance Evaluation (BPE) Programme. An overarching aim of the BPE programme was to assemble comparable data and knowledge about a large number of buildings to enable analysis across the body of case study information, leading to generic findings conclusions and learning for the sector as a whole. As part of this Programme, the Centre for the Built Environment (CeBE) were successful in securing over £500,000 of external funding to undertake six post construction and early occupation studies (25% of all of the domestic projects awarded under the Technology Strategy Board BPE Programme) and two in-use performance and post occupancy evaluation studies. Additionally, all participants involved in the wider BPEP were required to adhere to standardised BPE practices based on the Leeds Beckett University Coheating Text Protocol.

Research outputs

  • Gentoo Passivhaus Racecourse Development, Sunderland
    Type of study – Post construction and early occupation.
  • Gentoo Passivhaus Racecourse Development
    Type of study – In-use performance and post occupancy evaluation.
  • Dormary Court, York
    Type of study – Post construction and early occupation.
  • Dormary Court, York
    Type of study – In-use performance and post occupancy evaluation.
  • Lancaster Cohousing Development, Lancaster
    Type of study – Post construction and early occupation.
  • Community in a Cube (CIAC), Riverside One, Middlesborough
    Type of study – Post construction and early occupation.
  • Derwenthorpe, York
    Type of study – Post construction and early occupation.
  • Lea Field Court, York
    Type of study – Post construction and early occupation.
  • Fletcher MJ; Johnston DK; Glew D; Parker J (2017), An empirical evaluation of temporal overheating in an assisted living Passivhaus dwelling in the UK. Building and Environment, 121, Pages 106-118
    https://doi.org/10.1016/j.buildenv.2017.05.024
  • JOHNSTON, D. and SIDDALL, M. (2016) The Building Fabric Thermal Performance of Passivhaus Dwellings—Does It Do What it Says on the Tin? Sustainability, 8(1), 97; DOI:10.3390/su8010097.
  • JOHNSTON, D. and STAFFORD, A. (2016) Estimating the Background Ventilation Rates in New-Build UK Dwellings – is n50/20 appropriate? Indoor and Built Environment. Published online before print January 28, 2016, DOI: 10.1177/1420326X15626234.
  • JOHNSTON, D. MILES-SHENTON, D.FARMER, D. and BROOKE-PEAT, M. (2015) Post Construction Thermal Testing: Some Recent Measurements. Engineering Sustainability. Volume 168, Issue 3, June 2015, pp. 131-139. DOI: 10.1680/ensu.14.00048.
  • JOHNSTON, D. MILES-SHENTON, D. and FARMER, D. (2015) Quantifying the Domestic Building Fabric ‘Performance Gap’. Building Services Engineering Research & Technology (BSER&T). Volume 36, No.5, September 2015, pp.614–627. DOI:10.1177/014362441557034.
  • JOHNSTON, D. FARMER, D. BROOKE-PEAT, M. and MILES-SHENTON, D. (2014) Bridging the Domestic Building Fabric Performance Gap. Building Research & Information. Volume 44, Issue 2, pp.147-159. DOI:10.1080/09613218.2014.979093.

Cavity party wall thermal bypass investigations

This work was funded by Eurisol, the UK Mineral Wool Manufacturers Association. This project followed on from the Stamford Brook Field Trial, which identified significant heat losses via party wall cavities in terraced and semi-detached masonry houses, and proposed various techniques to eliminate or minimise the effect. The purpose of this study was to extend the work carried out at Stamford Brook, and help in the development of practical low cost solutions to mitigate of heat loss via party wall cavities.

Research outputs

Investigating the efficiency of Ground Source Heat Pumps

A collaborative 3-year research project funded by EPSRC in partnership with E.ON. The academic partners were: UCL (lead partners), Leeds Metropolitan University, Loughborough University, De Montford University, Kings College London, Cardiff University and the University of Greenwich. CCC uses the methodology of Action Research to engage users in the design of control systems which will reduce energy use (and therefore carbon emissions) in dwellings, whilst retaining or enhancing levels of comfort for the occupants. The aim was to achieve a 20% reduction in energy use through working more effectively with existing technologies and building fabrics, via the development of control systems which are both convenient to use and appropriate to the needs of users with a variety of lifestyles. The control systems were designed and tested in a way that complies with utilities’ CERT-2 obligations, and the project also developed design, installation and maintenance guidelines which will enable a wider application of important principles identified.

Research Outputs

  • Production efficiency of hot water for domestic use, P.J.Boait D.Dixon D.Fan A.Stafford, Energy and Buildings 54, November 2012, Pages 160-168
  • Electrical Load Characteristics of Domestic Heat Pumps and Scope for Demand-Side Management. P. Boait and A. Stafford, Proceedings of CIRED 21st International Conference on Electricity Distribution. Frankfurt, June 2011.
  • Performance and Control of domestic ground-source heat pumps in retrofit installations. P.J. Boait, D. Fan and A. Stafford, Energy and Buildings 43 (2011) 1968–1976.
  • Long-term monitoring and performance of ground source heat pumps. A. Stafford: Buildings Research and Information, Vol 39, Issue 6, pp566-573, 2011.
  • Predicting In-situ Heat Pump Performance: An Investigation into a Single Ground-Source Heat Pump system in the context of 10 similar systems. A. Stafford and D. Lilley. Energy and Buildings
  • The Effects of Weather Conditions on Domestic Ground-Source Heat Pump Performance in the UK. A Stafford. Accepted for SEB12 International Conference, September 2012, Stockholm

Assessing the fabric thermal performance of holiday homes

The aim of this project was to undertake a number of in situ measurements of the thermal performance and airtightness of a small number of new 2016 model fleet hire holiday homes. The in situ measurements were undertaken to enable the heat loss attributable to each holiday home to be disaggregated into its constituent components. All of these measurements were undertaken for Bourne Leisure Limited, on one the largest holiday home park operators in the UK. These measurements were undertaken to enable Bourne Leisure Limited to determine the optimum levels of insulation (and U-values) that should be specified for the main external elements of their fleet hire holiday homes.  This project presents the results obtained from undertaking detailed building fabric thermal performance tests on a small sample of new holiday homes. The results of these tests indicate that although a building fabric thermal performance ‘performance gap’ exists in all of the holiday homes tested, the results suggest that the ‘gap’ is much smaller than that documented for new build UK housing and may be more of a consequence of the way in which the design intent of these homes has been determined, i.e. a ‘prediction gap’, rather than a ‘performance gap’ between assumed and realised in situ performance. These results could be used by industry to develop more appropriate prediction tools that are relevant to holiday homes.

Research Outputs

Assessing the airtightness of holiday homes

The aim of this project was to quantify the air permeability and identify the main areas of air leakage associated with a number of prototype holiday home hire fleet models that were being produced by Atlas Leisure Homes. It is estimated that in the UK, 200,000 residents live in park and holiday homes all year round, the majority of which are elderly and on low incomes. As these homes are often thermally inefficient and leaky, these residents are some of the most susceptible in society to fuel poverty. The results identified a number of common air leakage areas within the test caravans, suggesting that there may be a fundamental industry wide issue associated with the way in which these homes are constructed which needs to be addressed. In addition, the results also indicate that utilising the air permeability metric within Sherman’s ratio (Q50/20) to approximate the average annual air infiltration rate, introduces a bias into holiday homes, due to their high surface to volume ratio. This bias is not unique to holiday homes and will be equally applicable to other building types with similar surface to volume ratios.

Research Outputs

Low carbon homes; prototype testing

Hill Housing Ltd and Leeds Beckett University employed a Knowledge Transfer Partnership Associate to assist in the evaluation of prototype low energy homes in Cambridge. The associate, supported by Leeds Sustainability Staff undertook design reviews, building performance testing, in use monitoring, post occupancy evaluation of the home and identified many successes and identified improvements that could be taken forward into the main multi home scheme. The homes themselves outperformed all the homes the LSI have previously tested; the performance gap that was measured was within the margin of error of the test, meaning that this may be the first home built in the UK, that has been tested, without any measurable performance gap at all.

Research Outputs

UK Passive House Conference, October 2019, Mainstreaming Passivhaus by 2030, Manchester, UK, - Chris Gorse speaker profile

Building Performance Evaluation for New Build Social Housing

Wakefield District Housing (WDH) and Leeds Beckett University (LBU) were successful in securing funding for a Knowledge Transfer Partnership. The project focussed on evaluating the performance of new build social sector housing.

The application of Dynamic Thermal Simulation models to WDH new build housing demonstrates the potential to evaluate a wide range of construction options at design stage. The DTS analysis work presented here also shows how calibration of models against measured and metered data can improve their accuracy and usefulness in considering alternative scenarios. The potential changes in construction and their impact on energy performance (and utility bills) has been quantified in this report. The DTS analysis also illustrates the potential risk of overheating in low-energy dwellings but also that this can be mitigated through simple design and operational changes, such as internal blinds or increased window opening angles.

As a whole, this in-use monitoring data demonstrates that the new build dwelling currently owned by WDH Ltd. are relatively well performing. The in-use monitoring data does however also illustrate the wide range of user behaviour in the context of thermal comfort and also, some scope to offer advice to tenants on how small changes in behaviour may help them to reduce utility costs without adversely affecting their thermal comfort.

Regulations and standards case studies

The gold standard for measuring the Heat Transfer Coefficient in buildings

The electric “co heating” test, which is in the process of being developed into an international CEN-standard and has been used by other institutions (both in the UK and abroad) as the reference test for assessing the aggregate performance of the building fabric in both new and existing dwellings. The electric coheating test has also been used to validate other building fabric thermal performance methodologies and is forming the basis of future research into validating building fabric thermal performance through the use of smart meter data. A quasi-steady state test method undertaken on an unoccupied dwelling to quantify the Heat Transfer Coefficient (HTC) of the dwelling in W/K. Currently in the process of being converted into a CEN Standard.

Research outputs

Achieving air tightness in practice

This Department of Communities and Local Government funded project considered the overall conclusions and key messages obtained through design assessments, construction observations, discussions with developers and pressurisation test results. The project analysed the airtightness performance of current UK housing, the implementation and impact of current and future legislation and identified potential areas for future work.  Following an initial literature review, the project adopted an action research methodology that involved the research team working very closely with 5 developers to investigate the practical design and construction issues that arise in making improvements to the airtightness of speculatively built mainstream housing. Two construction types were represented in the project, masonry cavity and steel frame.  The project highlighted a number of issues that need to be considered when constructing dwellings to meet a particular airtightness target. Suggesting that certain construction types appear to be intrinsically more airtight than others, complexity of the design can have a significant effect on airtightness, certain approaches to improving airtightness are likely to be both more successful and more robust than others and that achieving consistently high levels of airtightness in dwellings may prove difficult within existing design and construction cultures.

Research Outputs

Standardising how to measure the efficiency of buildings

Based upon our International reputation associated with undertaking electric coheating tests, Professor David Johnston was invited to become an expert member of the British Standards Institution B/540/9 and CEN Technical Committee 89 Working Group 13 Task Group 5. As part of his CEN Working Group role, he has been working with European Colleagues to develop a new European (CEN) standard based upon the Whole House Heat Loss Test Method (Coheating) developed at Leeds Beckett University. The new standard is entitled “Thermal insulation – Construction products, building elements and structures – In-situ measurement of thermal performance – Testing of completed buildings Part 1: Data Collection”.

Research Outputs

For more information about this project please contact us.

Reliable building energy performance characterisation based on full scale dynamic measurement

After building a strong reputation in building performance characterisation, the Centre for the Build Environment (CeBE) at Leeds Beckett University were invited to participate in the International Energy Agency Annex 58. The ultimate goal of the Annex is to develop the necessary knowledge, tools and networks to achieve reliable in situ dynamic testing and data analysis methods that can be used to characterise the actual energy performance of building components and whole buildings.

Research Outputs

Early investigations into the effectiveness of retrofits

The overall objective of this project was to define a coherent conceptual and analytical framework within which the technical requirements for the next three reviews of Part L can be debated and decided. The key objective of the project was to chart a possible course specifically for fabric performance out to 2013 and later. The L1 project was carried out for the ODPM Building Regulations Division under the Building Operational Performance Framework by the FMNectar consortium.

Research Outputs

  • LOWE, R.J. and WINGFIELD, J. (2005) Fabric Insulation – Ways of Further Raising Performance Standards for all Types of Building Fabric - Cost Effectiveness of Thermal Insulation – Costing and Evaluation, Report to ODPM
  • LOWE, R.J. and WINGFIELD, J. (2004) Fabric Insulation – Ways of Further Raising Performance Standards for all Types of Building Fabric - Interim Report on Insulation Standards in Selected European Countries, Report to ODPM
  • LOWE, R.J. and WINGFIELD, J. (2004) Fabric Insulation – Ways of Further Raising Performance Standards for all Types of Building Fabric - Final Report on Insulation Standards in Selected European Countries, Report to ODPM
  • LOWE, R.J. (2004) Workshop on Task 1 deliverable - initial exploratory report on cost effectiveness of thermal insulation, Report to ODPM
  • LOWE, R.J. (2004) Initial Exploratory Report on Cost Effectiveness of Thermal Insulation, Report to ODPM

Investigation routes to achieve higher performing homes

The project was undertaken at the request of the Joseph Rowntree Foundation with the prime intention of instigating debate over future developments in energy efficiency aspects of the Building Regulations in the UK. The report presents a critical review of current regulations, mainly with respect to space heating and the performance of the thermal envelope. The performance of the thermal envelope, as built, is a major determinant of overall environmental impact, with implications that extend further into the future than any other physical aspect of the dwelling. While energy use and carbon emissions for lighting and appliances will account for a progressively larger proportion of the domestic sector's total over the next twenty years, we do not consider that the Building Regulations are an appropriate tool to deal with these categories of end-use.

The project report identified a range of technical, regulatory and policy developments which should be pursued in order to ensure a significant reduction in energy consumption and greenhouse gas emissions from buildings in the 21st Century. Although it is focused on dwellings, much of the discussion is relevant to other building types.

Research Outputs

Comprehensively evaluation of an enhanced energy performance home

This project examined whether an energy performance standard similar to the 1995 Swedish regulations could reduce space heating and associated CO2 emissions in new UK dwellings by 80% compared with those built to the then current standards, while guaranteeing affordable warmth and dramatically reducing fuel poverty in new housing. Such a standard could in principle form the basis for future revisions to the UK Building. Its implementation would face a number of barriers. The construction industry would need to be convinced that the standard was workable, that costs were proportionate to the objectives and that the risk of building failures and defects was acceptable.

The St Nicholas Court Field Trial was set up in 1999, with funding from the Joseph Rowntree Foundation, the Housing Corporation and from the DETR under the Partners in Innovation Programme, to address these issues. The project sought to comprehensively evaluate the impact of an enhanced energy performance standard in the context of a development of 18, timber-framed houses built at St Nicholas Court for York Housing Association by Wates Construction Ltd.

Research Outputs

Early investigations into the effectiveness of retrofits

In the early to mid 1990s the UK government funded a series of demonstration projects in local authority housing designed to implement a wide range of energy saving measures which could be incorporated into modernisation programmes. This programme (the Greenhouse Programme) ran from 1991 to 1994 and funded some 183 schemes (over 50,000 dwellings) of which the York project was one. In common with many energy demonstration projects, the York Project had two main aims. The first was to confirm that the application of readily available technology could deliver significant energy benefits within the context of a routine local authority housing modernisation programme. The second was to extract lessons for the operation of future energy conscious modernisation schemes.

The project consisted of three schemes, which were carried out in the early to mid 90s and monitored over a two year period. Results indicate that modernisation schemes have a very important part to play in reducing CO2 emissions and that improvements in the region of 50% can be achieved at modest cost using well proven (early 1980’s) technology. The possibility of additional improvements are also identified which could see emissions fall by a further 30% to 40%.

Research Outputs

Condensation modelling of theoretical and real world details

The project, ‘Impacts of Improvements to Part L and Robust Construction Details (RCD) on Part C’ was funded by the Department of Communities and Local Government and consisted of a fieldwork element, undertaken by Leeds Metropolitan University, and a modelling element carried out by the Bartlett School of Graduate Studies, University College London. The fieldwork consisted of the analysis of design material and site surveys from 16 housing developments constructed to Part L 2002 and adopting the Robust Construction Detail route to compliance. The results of the analysis were used to enable condensation modelling that took into account not only the guidance of robust details but also the way in which construction details were actually designed and, perhaps more importantly, constructed. The modelling element of the project sought to identify the extent to which the ‘as built’ details give rise to a significantly increased condensation risk as compared to the relevant ‘standard’ robust construction details, as defined in the guidance.

Research Outputs

Knowledge exchange for low carbon construction

The LowCarb4Real project has been carried out by an interdisciplinary partnership of Leeds Metropolitan University, University College London, Leeds University and the Good Homes Alliance, with funding from the UrbanBuzz Programme. This partnership has been supported by an advisory group of key stakeholders that included representatives from CLG, Taylor Wimpey, Redrow Homes, the Zero Carbon Hub, Construction Skills, National Trust, the Housing Corporation, the Home Builders Federation and the Sustainable Building Association (AECB).

The LowCarb4Real project was designed to develop the knowledge necessary to make Low & Zero Carbon housing a reality, where it matters, “on the ground”. It sought to set up a knowledge exchange programme based on the lessons from the Stamford Brook housing field trial and the experience of those developers seeking to build beyond current building regulations. The Stamford Brook field trial was an action research project funded by the Department for Communities and Local Government (CLG) and based around a 700 house development undertaken by Bryant Homes and Redrow Homes, on land owned by the National Trust. The 6 year field trial sought to assess, in a comprehensive way, the issues involved in improving the carbon performance of mainstream house building. It has generated an unprecedented amount of learning related to airtightness, envelope integrity and systems performance, at all levels including building physics, dwelling design, site management, workforce training and procurement systems. Given the challenging regulatory targets proposed by government aimed at Zero Carbon new housing within 10 years, it is crucial that the learning from field trials such as Stamford Brook is captured, refined, contextualised and embedded as thoroughly as possible within the house building industry. The project also seeks to provide a model for industry based research and knowledge exchange.

Research Outputs

Embedding flood protection into regulations

The recent instances of severe flooding in the UK together with predictions on future flooding from the OST Foresight project have given rise to significant interest by Government, financial institutions, insurers, the construction industry and the general public for the need to improve the local flood protection of buildings. This has been driven by the requirement to protect the health and safety of the individuals living and working in affected properties, as well as the need to reduce the economic cost of flooding. The location of developments and buildings and their height above ground and local water levels are planning issues covered in Planning Policy Guidance which encourages development away from areas at risk of flooding. However, there is a level of residual risk for developments in marginal areas and in areas that become at risk as a result of climate change. Accordingly, it is essential that new developments are constructed appropriately to minimise the risk of flooding to occupants and users of buildings.

The flood protection industry, regulators and other stakeholders in the management of flooding are concerned about the lack of detailed knowledge on the resistance and resilience to flood waters of building materials, construction methods and building designs, and also the effective use of flood protection measures. There is a lack of both field performance data and also science-based information on how buildings, walls and floors behave in flood conditions. The use of inappropriate building materials could result in poor performance and in the extreme could affect the structural performance of buildings and the health of occupants. Current guidance on improving the flood resistance of new and extended buildings has, in the main, been developed on the basis of expert opinion and there is now a clear need to enhance our knowledge through scientific analysis. The aim of this project was to identify how existing and new knowledge could be incorporated into the Building Regulations and to produce guidance for new dwellings consistent with Government initiatives and common construction practices. A wide variety of individuals and organisations were consulted and contributed to the final outputs. The role of Leeds Metropolitan University in the project was to provide support to the other team members in terms of specialist knowledge of construction materials, construction forms, construction technology and building regulations. 

Research Outputs

Retrofit performance evaluation case studies

Investigating risk and performance of partial and whole house retrofits

This £2.7 million is project, funded by the Department for Business, Energy and Industrial Strategy and is one of the largest domestic retrofit projects to have ever been attempted in the UK.  The results on risk and performance will guide future retrofit policy.  It will critique thermal models including dynamic simulation models (DSM) and the Government’s Standard Assessment Procedure (SAP), as well as hygrothermal simulations that are currently used to predict performance and risk, and use building performance evaluation (BPE) field trials, including the Leeds Beckett Coheating Test and novel assessment methods such as the QUB and Pulse testing equipment, to measure and explore how single measure and whole house retrofit impact homes.  The project will involve undertaking 150 surveys to explore why retrofit performance often deteriorates and will also undertake 31 retrofits on case study homes in the North of England. The project is a consortium with the University of Salford who will investigate retrofits in their energy house facility; Loughborough University, who will undertake hygrothermal investigations into retrofits in their laboratory as well as; Lucideon Ltd who will evaluate the properties of common UK building materials in their materials testing facility.

Research Outputs

This project is currently in progress, if you are interested in taking part in one of the surveys you can find more information here or contact the LSI to find out more.

Investigations into a phased whole house retrofit in an environmental chamber

The Saint-Gobain Energy House Project was a two phase collaborative research project undertaken by the LSI in collaboration with the University of Salford and Saint-Gobain Recherché. It was the first full-scale retrofit project ever undertaken in a controlled environment in which the change in thermal performance resulting from the fabric retrofit of a Victorian solid wall house was measured.

Phase 1 of the project involved a staged programme of fabric retrofit to the test house. This allowed the impact of retrofit measures applied to individual thermal elements, combinations of elements, and a whole house retrofit, to be assessed. Phase 2 investigated the impact of a whole house fabric retrofit on the retrofitted test house and an untreated adjoining house.

In both Phase 1 and 2, quantitative measurements of thermal performance were obtained from the test house; these included the whole house heat loss value (heat transfer coefficient), in situ U-values, and the air permeability value. Qualitative data, such at thermography and construction observations, were gathered to gain greater understanding of the retrofit process and identify potential improvements to retrofit systems. Thermal modelling of all junctions was undertaken to assess the change in thermal bridging characteristics resulting from retrofit. The project also involved work to assess thermal comfort of occupants and experimental work to validate a new dynamic whole house heat loss test (QUB test).

Research Outputs

Evaluating retrofits of no fines concrete homes

The Innovate UK S-IMPLER thermal upgrade project was undertaken in collaboration with technology providers Tensor Systems, VRM Technology and the Building Research Establishment all in partnership with the Northern Ireland Housing Executive. As part of the S-IMPLER project, the LSI is directly responsible for testing the in situ fabric performance of dwellings both before and after retrofit. This provides the consortium with valuable data and understanding of the fabric elements within the building. It also allows the group to measure actual improvements in fabric performance and quantifies which elements of the fabric upgrades have been successful. In addition to the fabric testing, the LSI has contributed technical guidance throughout the project, particularly in the development of the retrofit strategy.

Research Outputs

Leeds was designated a core city for trialling the Government’s Green Deal domestic energy efficiency policy. Leeds Beckett University undertook a monitoring and testing program on 65 dwellings to investigate the effectiveness of the insulation measures installed and to understand any underperformance. This report outlines the findings from a series of investigations including; surveys, air tightness tests, co heating tests, in situ U-value tests, hygrothermal and thermal bridging modelling, in use monitoring and occupant interviews. The surveys revealed that the ‘whole house approach’ to retrofit was, more often, missing, and quality assurance around insulation detailing was regularly absent, leading to avoidable errors and potentially embedding problems in the installations. Furthermore, moisture issues were, in the majority of instances, over-looked or made worse despite over half the sample having some form of damp. Despite this, energy savings were observed and the appearance of the dwellings were improved, thus apparent satisfaction was generally high, even though the installs were imperfect and moisture problems were introduced.

Research Outputs

  • Gorse, C.A.,& Glew, D., Johnston, D., Fylan, F., Miles-Shenton, D., Smith, M., Brooke-Peat, M., Farmer, D., Stafford, A., Fletcher, M. and Thomas, F. (2017) Core cities Green Deal monitoring project – Leeds, 2017, Department of Energy and Climate Change.
  • Fylan, F., Glew, D., Smith, M., Johnston, D., Brooke-Peat, M., Miles-Shenton, D., Fletcher, M., Aloise-Young, P. and Gorse C. (2016) Reflections on retrofits: Overcoming barriers to energy efficiency among the fuel poor in the UK, Energy Research and Social Science, 190-198
  • Hardy A, Glew D, Gorse C, Fletcher M, (2018), Validating solid wall insulation retrofits with in-use data, Energy and Buildings, 165, 200-205
  • Glew, D.W., Smith, M., Miles-Shenton, D. and Gorse, C. (2017) Assessing the quality of retrofits in solid wall dwellings, International Journal of Building Pathology and Adaptation, 35 (5), 501-518

Evaluating the performance of novel Internal Wall Insulation

This report presents the preliminary findings from before and after building performance evaluation (BPE) field trials undertaken to measure the impact of 6 TIWI and 1 conventional IWI retrofits. Their impact on thermal bridging and hygrothermal models identified how they affected moisture risk. Dynamic simulation models predicted the energy demand reductions to evaluate potential carbon and fuel bill savings. Coheating test measured the reduction in the heat transfer coefficient (HTC) measured in W/K, which describes the holistic impact on the home’s heating demand.  In addition, blower door tests and heat flux measurements quantified the difference that the retrofits had on infiltration (uncontrolled air leakage) and fabric heat loss, i.e. wall U value measured in W/m²K, respectively. Appraisal of the installation costs and how the TIWI products could overcome installation barriers was undertaken, supported by surveys in 100 homes to identify insulation and dwelling characteristics that affected costs or risks, such as requirements to replace plumbing, boilers & radiators, apply decoration or repair damp walls.

Research Outputs

This project is currently in progress, if you would like any more information, please contact us.

Evaluation of Heat Pump Performance

Harrogate Borough Council has placed itself in the forefront of sustainable development of existing social housing stock by installing Ground Source Heat Pump technology in around 80 properties, with plans for further installations in the future. Ground Source Heat Pumps extract heat at relatively low temperatures from an external ground loop or borehole, and transfer this heat to water in a heating system, raising its temperature sufficiently to provide both space heating and domestic hot water. The system can be supplemented by a small amount of electrical resistance heating to cover any shortfall and to raise domestic hot water temperatures to high levels for short periods, e.g. during pasteurization cycles. Some monitoring of heat pump operation and performance has already taken place and some (limited) contextual information (building type, occupancy, maintenance etc.) is also available. This data has been gathered by Harrogate Borough Council as part of normal operations, without, as yet, any attempt at a systematic analysis of heat pump performance across the Borough. This project aims to systematize existing data, using the conclusions drawn to inform the scope and methodology of future data collection. As far as is practicable at this stage it will assess the energy cost and CO2 savings achieved by the systems, and will develop in-depth case studies of a small number of selected installations via collection of additional data.

Research Outputs

Evaluating airtightness in BISF and solid brick social housing

Wakefield District Housing (WDH) commissioned the Leeds Sustainability Institute (LSI) at Leeds Beckett University to undertake pressurisation tests and thermographic surveys on 20 semidetached dwellings.  The results showed that there was no noticeable improvement in the airtightness of dwellings that had EWI compared to those without EWI in either BISF or solid walled dwellings. A larger sample size of BISF homes without EWI and both solid walled properties with and without EWI would be needed to assess if this finding was statistically significant. CO2 decay analysis was used in an attempt to validate the blower door results however the results were inconclusive due to a low sample size and an uncontrolled conditions due to occupant activity. Improving air tightness is not the main function of EWI and this has been sustained by our findings. The results confirm that the fabric performance benefit of EWI is restricted almost exclusively to improving wall U values. i.e. reducing heat loss through the fabric, not affecting heat loss through uncontrolled ventilation in the dwellings.

Research Outputs

For more information about this project please contact us.

Quantifying party cavity wall heat loss

Leeds Beckett University and Cambridge Energy were successful in winning a research project from BEIS to investigate thermal losses from party walls. Detailed physical measurements and thermal modelling of heat loss from 54 dwellings with party walls were undertaken, to find out whether interventions are justified nationally.

Evaluating the success of MVHR retrofits

The aim of this project was to assess the effectiveness of the whole house mechanical ventilation and heat recovery (MVHR) systems within the existing UK housing stock.  This was investigated via field trials into homes where MVHR was installed as part of a comprehensive energy efficiency and environmental improvement package. Evaluations were made in terms of energy use, thermal comfort, internal air quality and acceptability to tenants.

Research outputs

  • Lowe R and Johnston D (1997) A Field Trial of Mechanical Ventilation with Heat Recovery in Local Authority, Low Rise Housing.

Product developments and patents case studies

Developing an Innovative Solution for Eaves Insulation

Thermal bridging calculations that were undertaken to assess the thermal performance of the ARC T-Barrier product. The calculations were undertaken by the Centre for the Built Environment within the Leeds Sustainability Institute at Leeds Metropolitan University as part of a collaborative project with the product’s developer ARC Building Solutions Limited. The project was supported by a Technology Strategy Board Innovation Voucher.

Designs for the party wall/external wall abutment junction for masonry and timber frame constructions were thermally modelled to compare the thermal bridging attributes of junctions with the ARC T-Barrier product installed against junctions with a more conventional cavity barrier product that is also manufactured by the Company. Comparisons were also made with the published linear thermal transmittance (Ψ-value) for the corresponding Accredited Construction Details (ACD). Potential options for improving the ARC T-Barrier product for use in timber frame applications were explored.

Research outputs

For more information about this project please contact us.

Investigating the performance of novel floor insulation

It is estimated that around 80% of UK homes have uninsulated ground floors despite substantial benefits that can be achieved when retrofitted. The benefits of insulation are often measured via disaggregated elemental point heat flux measurements, to calculate in situ U values. However, previous work suggests that this approach may be unreliable due to the heterogeneous nature of building elements. This paper presents the results obtained from a series of aggregate and disaggregate in situ fabric performance tests on a case study dwelling that has undergone a suspended timber ground floor insulation retrofit. The results demonstrate that the most appropriate method to adopt to assess the impact of ground floor insulation retrofits would be to adopt an aggregate measurement approach, which measures the change in overall dwelling HTC, rather than a series of changes in point heat flux measurements.  By adopting such an approach, it was found that the HTC was reduced by 43 ± 18 W/K, which is equivalent to a 24% reduction. The tests also found that the case study house was twice as leaky as the average UK house and a heat loss of 18.2 W/K was attributed to a reduction in infiltration via Sherman’s N/20 assumption.

Research outputs

  • Glew, D., Johnston, D., Miles Shenton ,D., Thomas, F., (In press), Measuring the effects of ground floor insulation, Building Research & Information, tbc

Evaluating the performance of novel Internal Wall Insulation

This report presents the preliminary findings from before and after building performance evaluation (BPE) field trials undertaken to measure the impact of 6 TIWI and 1 conventional IWI retrofits. Their impact on thermal bridging and hygrothermal models identified how they affected moisture risk. Dynamic simulation models predicted the energy demand reductions to evaluate potential carbon and fuel bill savings. Coheating test measured the reduction in the heat transfer coefficient (HTC) measured in W/K, which describes the holistic impact on the home’s heating demand.  In addition, blower door tests and heat flux measurements quantified the difference that the retrofits had on infiltration (uncontrolled air leakage) and fabric heat loss, i.e. wall U value measured in W/m²K, respectively. Appraisal of the installation costs and how the TIWI products could overcome installation barriers was undertaken, supported by surveys in 100 homes to identify insulation and dwelling characteristics that affected costs or risks, such as requirements to replace plumbing, boilers & radiators, apply decoration or repair damp walls.

Research Outputs

This project is currently in progress, if you would like any more information, please contact us.

Investigating the impact of heating system deaerators

In the UK, approximately 16% of the energy use can be attributed to domestic wet central heating systems. Government financial support and advances in technology have led to boilers becoming more efficient and a range of technologies are now available that claim to be able to improve the efficiency of domestic wet central heating systems. One such low cost technology is a passive deaerator.

This article presents the results obtained from installing a passive deaerator on the closed loop of a gas-fired wet central heating system, under controlled conditions in the Salford Energy House. The results indicate that although marginally less heat output was required from the boiler when the passive deaerator was operating, these savings are more or less out weighted by the boiler short cycling more frequently. Consequently, the overall reduction is gas consumption achieved by utilising the passive deaerator device is only of the order of 0.5%; this scale of savings may just be a consequence of measurement noise. The implications are that although a marginal benefit may be attributed to these products, if short cycling takes place, then these savings may become insignificant. Practical application: This article describes a test method that has been used to quantify the energy savings that could be achieved by installing a passive deaerator on the closed loop of a wet central heating system. Although the results indicate that the energy savings associated with using such a device are likely to be marginal, the test method described could be used to test a range of other devices that claim to improve the performance of domestic wet central heating systems, to directly compare before and after performance.

Research outputs

  • Johnston, D.K., Glew, D., Miles-Shenton, D., Benjaber, M. and Fitton, R. (2016) Quantifying the performance a passive deaerator in a gas-fired closed loop domestic wet central heating system, Building Services Engineering Research and Technology, 38, 3, 269–286

A product to compliment EWI and combat condensation risk

Mould growth and surface condensation are problems for many dwellings, and the retrofitting of insulation can increase the risk of these occurring. This is especially the case for historical solid wall properties receiving external wall insulation (EWI), which often have architectural details at the roof eaves that cause discontinuities in the insulation and so can result in excessive thermal bridging. This paper presents the results of an investigation into retrofitted solid wall properties where modelling is used to investigate the problem and effectiveness of insulated coving products which are designed to reducing thermal bridging. Thermal modelling is undertaken to establish the optimum design to reduce risk. The insulated coving was found to be effective in reducing thermal bridging in all the scenarios investigated and to reduce moisture risks occurring in some solid walls situations.

Research outputs

  • Glew, D., Brooke-Peat, M. and Gorse, C. (2017) Modelling insulated coving's potential to reducing thermal bridging and moisture risk in solid wall dwellings retrofitted with external wall insulation, Journal of Building Engineering, 216-223

Contact the Leeds Sustainability Institute