Sustainable Buildings: Improving Energy Efficiency in TraditionalBuildings International Conference Energieke Restauratie Hanze Univeristy, Groningen 19 September 2013 Soki Rhee-Duverne Architectural Conservator Building Conservation Research Team
Structure Part 1 • Background to English Heritage • Policy drivers for energy efficiency • Our philosophy and approach. Part 2 • Research; • Publish guidance notes and provide training.
Who are we? • English Heritage (officially the Historic Buildings and Monuments Commission for England) is an executive non-departmental public body (NDPB) of the British Government and is an executive agency of the Department for Culture Media and Sport (DCMS), advising the Secretary of State on managing the historic built environment. • As an NDPB we are semi-autonomous giving us the ability to provide independent advice. • Our sponsers include DCMS, Department of Environment, Farming and Rural Affairs (DEFRA) and Communities & Local Government (CLG).
• We are the UK Government’s statutory advisor and a statutory consultee on all aspects of the historic environment and its heritage assets. • This includes archaeology on land and in the sea, historic buildings and areas, designated landscapes. This involves:
Our remit… • Management of EH Estate: over 400 sites and monuments; & and the National Monuments Records. • Grant aid: to organisations for the conservation of historic buildings, monuments and landscapes. • Advisory: to central Government on heritage protection and listing applications; & management of register of listed buildings and ancient scheduled monuments. • Advisory local councils on case work, planning issues and managing change. • Influencing Government policy: planning and building regulations. • Guidance & training: to professionals and homeowners. • Research: under the framework of the National Heritage Protection Plan.
English Heritage cycle…
How to adapt to increasing pressures on historic environment by climate change…
Carbon Legislation Policy drivers… • Climate Change Act 2008 • Energy Acts 2008, 2010 & 2011 Key strategies & policies • Carbon Plan 2011 • Green Deal & Energy Company Obligation • Energy Performance Certificates Key targets • GHG reduction targets of 50% by 2020 & 80% by 2050 from 1990 levels. • New build homes to be zero carbon by 2016 & all new non-domestic buildings by 2019. • & by 2050 all buildings are to be near to zero GHG emissions by 2050. 1.49 Carbon emissions • Domestic housing is responsible for approx. 25% of UK’s GHG emissions.
Carbon emissions - how big a contribution does the historic environment make? BUILDINGS Pre - 1919 dwellings Other sources Post - 1919 dwellings Commercial and industrial buildings
Housing stock… Housing stock • 22.4 million dwellings in England, of which 22% were built before 1919. • Approximately 6.5 million solid wall buildings without insulation in England.
Carbon emissions attributable to pre- 1919 buildings… Listed dwellings Dwellings in Conservation Areas Pre 1919 dwellings not in Conservation Areas Other dwellings
Historic and Traditional Buildings… Historic Traditional
Part of the solution… no exclusion for older buildings • English Heritage needs to offer practical solutions…or risks being seen as part of the problem . • Concerns: aesthetics/cultural significance & technical • Heritage value : loss of traditional features and change in appearance • Technical unknowns : solid wall insulation, quality control…
Adaptation concerns… • Loss of features • Altered appearance • Decay of fabric
Older homes are different… • Thermal Mass • Breathing buildings What are the risks? • Trapped MOISTURE!! What do you need to consider? • Adequate ventilation “Insulate tight, ventilate right” • Use hygroscopic materials • Minimise barriers to moisture flow
Constructive Conservation: It’s all about achieving the right balance… • Achieving the optimum balance between improving energy efficiency and preserving the cultural significance. • Adaptive Re-use: as buildings adapt with time - Functions change - Meet new requirements eg. H&S, energy efficiency.
Conservation Principles • Understand origins, evolution and associations of a place in its context. • Evaluate significance, as a whole and its elements. • Identify how significance is vulnerable. • Devise strategies to safeguard significance. • Implement options that cause least harm to significance. • Record & evaluate outcome.
Whole building approach … • Understand: - heritage values/significance of the building; - condition of the building fabric and building services; - energy use related to building occupation and operation; - energy performance of the building envelope and building services; - behaviour of the building fabric in response to heat and moisture; - user requirements and needs.
Whole building approach…every dwelling can improve its thermal performance • Identify opportunities to improve energy efficiency and sustainability and devise energy conservation measures from passive interventions such as draught proofing, to active measures such as changes in services, controls; to operational measures such as how a building is used. • Evaluate the effectiveness and value for money of such measures; • Assess their impact on heritage values/significance; • Assess the technical risks (e.g. increased risk of condensation); • Implement the optimum strategy and monitor the outcome.
Research …
Carbon challenge research… Aim: Develop the evidence base to enable more informed decisions to be made on improving the thermal and energy efficiency of traditionally constructed buildings. - Understand better & find suitable carbon adaptation solutions.
Background… Environmental Change Institute, Oxford University UK Government Regeneration Programmes: Pathfinder (2005) Programme
What are the problems? • Lack of data / insufficient evidence: - actual performance of whole buildings and individual building elements - material properties of traditional building materials. • Lack of informed guidance which are appropriate/sympathetic for traditional buildings • Uncertainties in current models and over-reliance on default data.
“ Energy Performance “All models are wrong but Certificates some are useful…” We challenge the presumption that old buildings are inherently inefficient and that they require the levels of upgrading indicated by current modelling techniques. Source: EHCS
Victorian Brick Terrace Houses…
Why? • Pre-1919 brick terrace housing with solid walls most common traditional building type in England. • 22% of English dwellings are built before 1919 (English Housing Survey, CLG, 2010) • The thermal performance of pre-1919 dwellings with solid wall construction is perceived as poor & to test that assumption. • Establishing the actual performance can contribute towards a more rational approach and inform debate on the energy efficiency of traditional buildings.
Gathering evidence base to inform refurbishment decisions / carbon solutions… • Thermal performance of traditional building elements; • Whole-house thermal performance and impacts of interventions; • Technical risks of insulation;
Calculated with brick @ Measured v. Modelled 0.77W/mK 0.56W/mK 0.44W/mK Measured 1.2W/mK Laboratory testing Walsall: Drylined with (insulated) plasterboard + paint/wallpaper Walsall: Plaster + wallpaper/paint Shrewsbury: Plaster + wallpaper/paint Englefield: Cement render Englefield: Bare painted brick Englefield: Drylined with plasterboard + paint/wallpaper Englefield: Plaster + wallpaper/paint 3.0 2.5 2.0 1.5 1.0 0.5 0.0 U-value, W/m2K Approach Fieldwork
Thermal performance of traditional building elements • U-values indicators of thermal performance and are used in calculations to assess energy & carbon performance of buildings. They are the basis for Standard Assessment Procedures (SAP) from which Energy Performance Certificates ( EPC’s ) derive from. • However, current understanding of U-values are based on default assumptions about building performance and have not been tested against real buildings.
Windows research: carbon solutions Various testing options Before and after repair
What is a U-value? • It is a measure of the rate of heat flow through a material. • It is expressed in W/m 2 K and shows the amount of heat loss in Watts per square metre of material when there is a temperature difference between inside and outside • The lower the U-value the better the insulation is provided by the material.
Thermal performance assessment of traditional windows
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