building resilience against overheating in housing and care...
TRANSCRIPT
Building resilience against overheating in housing and care homes
Professor Rajat Gupta Director of Oxford Institute for Sustainable Development, Oxford Brookes University
Exploring Resilience Conference18th May 2016, Cardiff
Structure of presentation• Background
• Overheating in UK housing: Insights from EPSRC SNACC project
• Mapping overheating risk
• Testing effective adaptations
• Presenting findings to residents and stakeholders
• Overheating in care settings: JRF funded research
• Empirical monitoring
• Climate modelling
• Interviews with designers, managers and residents
• Key messages
• Adaptation responses to climate change for new development in the growth areas, DEFRA (Led by Land Use and CAG consultants)
• SNACC project on Climate change adaptation of sub-urban neighbourhoods in UK, EPSRC
• Heat pumps in a changing climate, EPSRC CASE
• Design for future climate projects, Innovate UK
• Overheating resilience in new-build social housing, Building Performance Evaluation programme, Innovate UK
• Current and future risk of overheating in Care and Extra-care homes, Joseph Rowntree Foundation
Our climate adaptation and resilience research portfolio
Background
High emissions scenario
50% probability
A warming climate in the future is projected with heat waves and more frequent hot temperatures…
Summertime overheating in housing is happening currently: existing temperature in Oxford homes
Climate change, overheating and older people
• Climate change is expected to result in hotter and drier summers, with heat waves with greaterfrequency, intensity and duration.
• Heath evidence indicates that older people are particularly vulnerable to the effects of excessive heat.
• However in the UK awareness of thermal risks and vulnerabilities inolder age is focused more on coldthan on heat.
SNACC: Suburban neighbourhood adaptation for a changing climate
https://snacc.wordpress.com/
Overview of the SNACC project EPSRC funded project, 2009-2012, £640k
Multi-disciplinary team of researchers from Oxford Brookes University, University of West of England and Heriot-Watt University
Focused on suburban areas, because 84% of population lives there – place where domestic lives are most affected
How can existing suburban areas be best adapted to reduce further impacts of climate change and withstand on-going changes?
Which adaptation strategies perform best in terms of technical performance, practicality and acceptability
Six neighbourhoods in Oxford, Stockport and Bristol https://snacc.wordpress.com/
1. Identified:1. Six types of English suburbs across 3 cities
(Oxford, Bristol and Stockport) 2. Potential adaptation options (over 100 at
neighbourhood, garden and home scale)3. Climate change impacts and associated risks
2. Modelled and visualised feasible adaptation options and their outcomes
3. Tested the adaptation options in neighbourhood workshops with residents (for feasibility and acceptability)
4. Tested the neighbourhood responses, and a wider set of adaptations with stakeholders in each city
5. Established why adaptations are/are not being implemented, and what might enable residents and stakeholders to adapt
How did we research this?
St. Werburghs: exposed, historic87% mid-terrace
Upper Horfield: semi-exposed, new urban
extension47% end/semi-detached
Summertown: Shaded, pre-war suburb62% end/semi-detached
Botley: semi-exposed, public transport
suburb95% end/semi-detached
Bramhall: Moderately shaded car suburb 72% detached homesCheadle: semi-exposed, social-
housing suburb95% end/semi-detached homes
BRISTOL
Case study neighbourhoods
OXFORD
STOCKPORT
Mapping future overheating risk using DECoRuM-Adapt model
Bristol: St. Werburghs (Inner historic suburb)
Bristol: Upper Horfield (Higher density urban extension)
Oxford: Botley (Public transport suburb)
Oxford: Summertown (Pre-war ‘garden city’ type suburb)
Stockport: Bramhall (Car suburb)
Stockport: Cheadle (Social-housing suburb)
Regionally: Homes in the southeast (Oxford) are more likely to be vulnerable before
homes in the southwest (Bristol) and north (Stockport). Neighbourhood and garden: Orientation: East and west facing homes Homes on exposed streets (e.g. no shading from trees) Darker pavement and external wall and roof surfaces increase solar energy
absorption and contribute to higher microclimatic temperatures.Home characteristics: Built form: having either or both a small floor area and limited exposed
external wall area can lead to a higher probability of overheating Extent of glazing: Having a greater glazing area vs. less glazing area Location of glazing: Presence of roof lights Lightweight home vs. heavyweight home.
Where do we find a greater degree of overheating risk?
Testing individual measures to tackle overheating using dynamic thermal simulation
Initial findings: shading is essential
Package 1 (walls): High albedo external wall insulation, solar-selective low-e double glazing and shading
Package 2 (roof/floor): High albedo roof, roof insulation, floor insulation and shading on existing glazing
Package 3 (heating systems): Insulation for hot water tank, primary pipework insulation and temperature controls
Package 4 (all): Combines all measures
Developing packages to tackle overheating (and mitigation)
0 5 10 15 20
Package 4 (all)
Package 3 (heat sys.)
Package 2 (floor/roof)
Package 1 (walls)
Basic Construction
Overheating potential (% hours)
Space heating requirements (kWh/yr)
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
Package 4 (all)
Package 3 (heat sys.)
Package 1/2 (full fabric)
2050 H 90%
Current climate
Residents likelihood of implementing summer measures
Suburb typology Inner historic
Pre-war Garden Inter-war Social
housing Car Medium-high
Case studySt W’burghs
BristolSummer-
town, OxfordBotleyOxford
CheadleStockport
BramhallStockport
HorfieldBristol
External solar shading
Internal shutters
External shutters
Solar film
Wall greenery
Green roof
Shaded outdoor space
Water butt
Rainwater harvesting system
Internal thermal mass
White roof and walls
Extend eaves
Lock-open windows
Reasons for being likely to choose an adaptation measure
Reasons for being less likely to choose an adaptation measure
• Cheap, convenient (i.e. DIY)• Attractive• Lifestyle benefits (enjoyable,
reduces noise)• Energy cost-savings • Environmentally friendly (reduces
carbon emissions)• Improves current climate
comfort• More efficient• Potential for financial support
(grants and subsidies)• Could be done easily with other
home renovations
• Too expensive as initial cost• Major building works required• Bulky and unattractive• Potential damage to property from
measure• Loss of house space• Inappropriate housing orientation for
measure• Lack of space or sunlight required
for measure• Simpler behavioural alternative• Requiring external approval (e.g.
from housing association)
Key findings At the neighbourhood scale, introduction of blue and green infrastructure is likely
to bring cooling benefits and is welcomed by residents. However, there is uncertainty over implementation, particularly about cost
and responsibility for installation and management. ‘Adaptive retrofitting’ should be combined with ‘low-carbon retrofitting’ of UK
housing to avoid lock-in effect and sub-optimal retrofitting Package development
As an individual measure, shading (externally) the glazing from incident solar radiation is most effective in reducing overheating hours. operation of shading devices may be a behavioural challenge.
• External insulation or any new external finishes be light in colour: minimise the influence of solar absorption which is projected to have an adverse impact in future summers. Some barriers to external insulation can include planning issues, costs, and
aesthetics Respect existing thermal mass. Balance fabric measures with internal gain
reduction and control (e.g. hot water tank insulation, pipework insulation): reduction of internal gains in older homes is significantly beneficial for both reduction of overheating and energy use.
Innovate UK Retrofit for Future Programme: deep retrofit of a 1990s Terrace in London
With Penoyre and Prasad Architects, London
Winner of 2011 AJ Retrofit award
(Penoyre and Prasad)
Overheating in care settings
https://www.jrf.org.uk/report/care-provision-fit-future-climate
Research study details• 15-month research study (Feb 2015-
Apr 2016) funded by Joseph Rowntree Foundation.
• Socio-technical case study based approach
• Led by Oxford Brookes University in collaboration with University of Manchester and Lancaster University
• Scope of study:– Examined how far existing care
homes and other care provision in the UK are fit for a warming climate, and
– Considered the preparedness of the care sector (both residential and extra care) with a focus on overheating.
Mixed-methods approach• Building surveys to identify design features that can enable
or prevent occupants and their carers to control their thermal environment
• Climate modelling using future weather data (2030s, 2050s and 2080s) in dynamic thermal simulation
• Monitoring of environmental conditions in the four case studies (June 2015 – September 2015)
• Qualitative Interviews with Designers, Development director/asset manger, Scheme manager, Carers and Residents to assess how building design, management and occupant practices address overheating risks and vulnerabilities
• Recommendations for policy and practice
Case study schemesCare homes: Single bedrooms with access to on-site care services.• Case Study A (42 beds / 2005)• Case Study B (23 beds / mid-late 19th c.)
Extra-care homes: Rented or purchased flats or bungalows designed for people with mobility difficulties, with help and support available in an emergency.• Case Study C (50 flats / 2006)• Case Study D (60 flats / 2012)
Case Study A
Case Study B
Case Study C
Case Study D
Indoor temperatures in case study buildings
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11/06/2015 01/07/2015 21/07/2015 10/08/2015 30/08/2015 19/09/2015
Tem
pera
ture
(deg
C)
Indoor temperatures in Bedrooms in the Case Study buildings across monitoring period (June - Sept 2015)
CsA Bed1 CsA Bed2 CsA Bed3 CsB Bed1 CsB Bed2 CsB Bed3CsC Flat1_Bed CsC Flat2_Bed CsC Flat3_Bed CsD Flat1_Bed CsD Flat3_Bed
- PHE Heatwave Plan ‘cool area’- CIBSE Guide A (2015) threshold indoor temperature for bedrooms (260C)
Short term heat wave:Case Study D residential areas
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00:0
005
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11:3
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09:3
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21:0
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08:3
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07:3
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19:0
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06:3
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18:0
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05:3
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27/06/201528/06/2021529/06/201530/06/201501/07/201502/07/201503/07/201504/07/2015
Tem
pera
ture
(˚C
)
CASE STUDY D: Indoor and outdoor temperatures in BEDROOMS over short-term heatwave period (30th June - 1st July 2015 ±3 days)
External temperature Flat 1 Bed (Southeast-facing)Flat 3 Bed (Southeast-facing)
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00:0
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23:0
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:45
10:3
016
:15
22:0
003
:45
09:3
015
:15
21:0
002
:45
08:3
014
:15
20:0
001
:45
07:3
013
:15
19:0
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:45
06:3
012
:15
18:0
023
:45
05:3
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:15
17:0
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021
:45
27/06/201528/06/2021529/06/201530/06/201501/07/201502/07/201503/07/201504/07/2015
Tem
pera
ture
(˚C
)
CASE STUDY D: Indoor and outdoor temperatures in PRIVATE LIVING ROOMS over short-term heatwave period (30th June - 1st July 2015 ±3
days)
External temperature Flat 1 Living (Southeast-facing)Flat 2 Living (Southeast-facing) Flat 3 Living (Southeast-facing)
• One short heat wave period (30th Jun – 1st Jul 2015).• High temperatures in all rooms before, during and after heatwave.• Indoor temperatures in these areas are above 260C for 46%-94% of the total monitored
period.
- PHE Heatwave Plan ‘cool area’ threshold indoor temperature (26°C)
- CIBSE Guide A (2006) thermal comfort bands (bedrooms: 230C ±3K; living rooms: 250C ±3K)
Current and future overheating risks in the case studies
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10
Bed
3 (F
F, S
E)
Loun
ge (F
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W/N
)
Man
ager
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(GF,
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ce (B
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Flat
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Case Study A Case Study B Case Study C Case Study D
% o
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pera
ture
Current climate 2030 2050 2080 Measured (2015)
Static method:
• Prevalent perception, from designers to front-line staff, that older people ‘feel the cold’.
• While cold seen to represent a bigger threat to older occupants’ health, there is less recognition that heat can also present a significant health risk.
• Low prioritisation of overheating and future climate change (briefing & design)
• Provision of warmth is associated with good care.
1. A culture of ‘keeping warm’: the perception that older people are vulnerable to cold, not heat
2. Mismatch between climate modelling and monitoring results underplays present day risks from high temperatures Modelling indicates some risk of future
overheating BUT little currentoverheating risk.
However empirical monitoring indicates prevalent and current risk of overheating, particularly during short-term heat waves.
Modelling weather files appear to be tooconservative for simulating overheating results that match; the monitored data most closely matched the 2050s-2080s climate period weather files.
Sensing system to detect overheating.
CIBSE Guide A 2006Living areas: 1% of occupied hours over 28degCBedrooms: 1% of occupied hours over 26degC
3. Lack of standardised overheating criteria and thresholds
No statutory maximum internal temperature for care schemes.
SAP Appendix P 2012Building: Significant risk if monthly mean internal temperatures over 23.5degC
PHPP 2007Building: 10% occupied hours over 25degC
WHO guidance:Health effects minimised in temperatures <24degC
HHSRS guidance:Adverse health effects increased in external temperatures >25degC
Heatwave plan for England guidance:Cool room/area temperatures <26degC
4. Lack of effective heat management in care settings due to design and management issues
• Disconnect between, and lack of communication from design intent to handover
• Separation of roles within care organisation creating confusion in terms of responsibilities
• Lack of investment in long-term physical strategies to tackle overheating
• Conflicts between existing passive cooling strategies and occupant requirements
• Centralised heating and hot water systems can lead to unwanted heat gains due to pipework.
5. Lack of awareness and prioritisation of current and future summer overheating risks
• Lack of preparedness at all levels(briefing, design, management, care living)
• Design briefs prioritise other issues-safety, security e.g. Window restrictors
• Managers aware of Public Health England Heatwave Plan – other staff unaware
• No consultation with occupants’ GPs about health risks.
• Ingrained practices of residents a barrier during heat waves: meals, clothes, washing
Key findings• Summertime overheating is both a current and future risk in care schemes,
yet there is currently little awareness or preparedness at all levels, from designers to frontline staff, to implement suitable adaptation strategies.
• Perception that older people ‘feel the cold’, but less recognition that heatcan also present a significant health risk.
• Design for overheating not commonplace; there is low prioritisation of overheating and future climate change (in briefing and design);
• Mismatch between the overheating risks predicted by climate modellingand those measured by empirical monitoring, which underplays present-day risks from high temperatures.
• Lack of effective heat management across the case studies is due to a number of design and management issues.
• Collaboration among government departments and professional institutions is necessary to harmonise and standardise health-related and building thermal comfort-related overheating thresholds.
Thank you for your attention!
http://architecture.brookes.ac.uk/research/lowcarbonbuilding/