Guest Blog by Jane Thomas
This is a personal summary based on the Passivhaus seminar, ‘Applying Passivhaus to Retrofit Projects’ at Ecobuild 2013 and of the data analysis report put together by the Technology Strategy Board: ‘Retrofit Revealed – The Retrofit for the Future projects data analysis report’ . http://www.innovateuk.org/_assets/pdf/publications/6231%20TSB%20Retrofit%20for%20the%20future%20AW5.pdf
It was followed by a presentation of various facts and figures drawn from a few of the case studies.
Retrofit Revealed – The Retrofit for the Future projects data analysis report
The information presented the first analysis of data collated from the Technology Strategy Board’s Retrofit for the Future programme, and a review of the final reports submitted by the Retrofit for the Future project teams.The Retrofit for the Future competition acted as a catalyst for the retrofit of homes across the UK, with an ambition of achieving an 80% reduction in the in-use CO2 emissions of each property. The properties were mainly two-storey dwellings, with a couple of bungalows included too. All homes had two or more bedrooms. A total of 86 projects were awarded funding of up to £150,000 each to demonstrate just what could be achieved.
Analysis of monitoring data provided by the Retrofit for the Future project teams aimed to:
- identify the energy and carbon performance achieved by Retrofit for the Future projects
- explore whether this performance is being achieved at the expense of other factors, such as occupant comfort or satisfaction
- identify common success factors, lessons and challenges from the delivery of Retrofit for the Future projects, to provide insights to the industry.
Key Findings
Of 37 properties included in the analysis, three achieved a reduction in CO2 emissions equivalent to over 80% compared with 1990 average levels. A further 23 achieved a reduction in CO2 emissions equivalent to between 50% and 80%.The analysis shows a strong correlation between good air-tightness and lower CO2 emissions.
The data also suggests that air-tightness and emissions reductions are usually being achieved without compromising the comfort of residents. Almost all of the properties in the analysis stayed within comfortable boundaries for temperature and relative humidity. The analysis also considers energy costs.
Keys to a successful retrofit project: Project Planning; Site Management; Understanding Supply Chains and Working closely with residents.
Perceived comfort can be improved:
(Source: Retrofit for the Future Projects data analysis report)
Common Challenges
Various challenges were encountered by the retrofit teams, though others managed to overcome most of the problems. These included:- Lack of competition, choice or availability of products and services
- Supply chain skills, quality and integration
- Unexpected changes to project team
- Site issues
- Planning
- Residents and their neighbours
- Cost overruns and delays
Other issues identified by a smaller number of project teams included:
- poor quality data or records relating to the property
- having to deal with multi-tenanted properties
- challenges around modelling, particularly where interventions are not included in SAP
- difficulties sourcing and working with monitoring equipment
- identifying and providing low energy appliances
- Procurement issues, for example working with a framework agreement with a limited choice of (non-specialist) suppliers.
Some challenges remain, however, and these may need intervention at a more strategic level:
- Local planning was an obstacle for many projects. Local approaches to planning help to create and preserve vibrant individual communities; however, lack of consistency in decision-making, uncertainty over what is permitted development, and the time and resources needed to secure planning permission presented challenges to Retrofit for the Future project teams
- Many of the product markets are immature, either in the UK or globally. Price volatility affected project budgets and long or delayed lead-in times were frequently blamed for project overruns. If low-carbon retrofit is to scale-up in line with Government ambitions, then product markets need to mature rapidly
- The supply chain for delivering whole-house low-carbon retrofit could face capacity issues as demand grows, and there will likely be opportunities for new players. In Belfast, the Grove Housing Association project significantly influenced the supply chain in Northern Ireland, such that there are now twelve businesses operating in the low-carbon retrofit sector, whereas previously there were none.
The Future
The analysis suggests that there are considerable challenges ahead for the retrofit market. Equally, it has identified some concrete examples of innovation, and further opportunities for product and service development.To support the development of a thriving retrofit market in the UK, the Technology Strategy Board has made the full data set from Retrofit for the Future available through a database called ‘embed’. This database provides a valuable resource for anyone considering a retrofit project. It can be accessed via http://www.retrofitanalysis.org (Registration required).
To understand more about the relationship between costs and carbon reductions, the TSB has launched the ‘Scaling-Up Retrofit of the Nation’s Homes competition’, which aims to stimulate significant cuts in CO2 emissions from existing homes.
The main retrofit analysis report can be viewed here.
Example Case Studies
The Oxford Whole House study is mentioned in the report. I found the other two via internet research.The Hounslow Council Passivhaus Retrofit
Using the Passivhaus Planning Package, bere:architects took a fabric‐first approach to the retrofit. The monitored data (appendix 6 & 7) demonstrates that this approach has worked very well in achieving a massive reduction in overall energy consumption, mainly by means of reducing the Specific Space Heating Demand of the house.The details of the Hounslow Council Passivhaus Retrofit can be viewed as a report here: http://www.bere.co.uk/sites/default/files/research/371gr%20130109jb%20RftF_Final_Report%20%28anonymised%29.pdf
Hockerton Housing Project
HHP has refurbished two homes in Newark, using low tech durable solutions including insulation, passive solar heating and community renewable energy to deliver 80% cuts in carbon emissions.Information about the Hockerton Housing Project Retrofit can be viewed here: http://www.hockertonhousingproject.org.uk/wp-content/uploads/2012/07/Case-Study-Retrofit-vOct2010.pdf
Oxford Whole House Carbon Reduction Project
This Oxford City Council Victorian semi-detached house in Nelson Street with two rear extensions added in 1972 and 2003, was described as a very cold house by the residents, especially the first floor bathroom that had three exposed external walls and a roof. Retrofit achieved a reduction in CO2 emmissions of 80.7%.Information about the Oxford Whole House Carbon Reduction Project can be found here: http://architecture.brookes.ac.uk/research/lowcarbonbuilding/whole-house-carbon.html
Other Links
Low energy building database: http://www.retrofitforthefuture.org/Retrofit Analysis reports from Institute for Sustainability: http://www.instituteforsustainability.co.uk/retrofitanalsyis.html
Delivering and funding housing retrofit: a review of community models: http://www.instituteforsustainability.co.uk/housingretrofit.html
Air-tightedness Pre- and Post-Retrofit
(Source: Retrofit for the Future Projects data analysis report)
