National Trust HRSC0054
Written evidence submitted by the National Trust
Call for Evidence on Heat Resilience and Sustainable Cooling
With our staff, members, volunteers and supporters, the National Trust is the biggest conservation charity in Europe. We protect and care for places so people and nature can thrive. Many millions share the belief that nature, beauty and history are for everyone. So we look after the nation’s coastline, historic sites, countryside and green spaces, ensuring everyone benefits. For everyone, for ever.
The National Trust cares for a wide range of sites and buildings of varying purposes, types, ages, architectural and building styles and materials, and uses – including domestic homes, commercial properties, and historically significant mansion houses and estates and visitor attractions. We have a strong organisational commitment to reach net zero by 2030.
Our climate is already changing and having an impact on the Trust – on the landscapes, buildings and collections we care for on behalf of the nation, but also on our visitor business, our staff and our ways of working. Heat resilience is a major concern in operational terms, as a conservation body, an employer and an operator of visitor sites. The need to ensure cooling can be achieved in a sustainable way as temperatures and need increases in the UK is also going to be vital to delivering the UK’s legal target to reach net zero by 2050. As such we welcome the Committee’s inquiry into a timely issue.
The scale of the climate crisis demands concerted action from the government to grow our resilience as a nation to protect people and places from the growing impacts of climate change. It will require every government department to take action. However, research we commissioned from Public First concluded that ‘action to prepare for climate change has stalled because it has been side-lined as an issue for the “environmentally few”, when it should be a key role of Government.
Unified action is needed. Leadership from Government is critical, but the UK is lagging seriously behind. The Climate Change Committee recently concluded that the UK were ‘strikingly unprepared’ for the effects of climate change. This is an issue of concern for the public – polling shows that currently, while 79% of the public are worried about how climate change will affect them personally, only 4% of the UK public think the country is well prepared for a changing climate.
We have responded selectively to the questions posed by the Committee, drawing primarily on our practical experience from the places that we care for.
The link between high heat and mortality, particularly among the elderly, is well evidenced; in the heatwaves of 2022, for example, the Office for National Statistics report that there were 2,803 excess deaths among those 65 and over.
For more information particular on the risks to human health, wellbeing, and productivity, of overheating in buildings, we refer to this research by UCL and ‘Tackling the climate and health risks of overheating in buildings.’
As a conservation charity, with a strategic plan for mitigation against climate change, and ambitious targets towards net zero, National Trust currently prioritises passive, natural cooling solutions over mechanical ones. Natural ventilation is well suited to the National Trust’s many historic buildings, allowing external air, through open windows, doors, chimneys, and flues to flush out warm air and promote a more stable temperature throughout the building. The thermal mass of historic buildings can allow them to more easily remain thermally stable in periods of intense heat.
Additional passive measures such as external or internal blinds and shutters, awnings and canopies reduce the amount of solar radiation entering a building and provide flexibility for occupants to control their use and balance heat gain. Enhanced adaptive measures may include the sensitive retrofit of awnings, shades, blinds and shutters to existing buildings, which may be subject to consent.
Where land is available, green and blue infrastructure can provide a cooling effect and can mitigate the impact of higher temperatures and heat stress. This may include trees in parks, and woodlands, hedgerows, wildflower verges and ponds, wetlands, and rivers. Trees can provide shade in the context of buildings, but need to be carefully sited, and species selected so that the trees are resilient to climate change, and higher temperatures into the longer term.
Such practical cooling design solutions may be accompanied by proactive adaptation strategies for the day-to-day behaviour in the way we use existing buildings, and adapt use and management of public places, to target promotion of access and activities to cooler outdoor, public spaces, for communities of greatest cooling need. This is particularly relevant to inner city, urban heat island areas. Green and blue infrastructure also offers valuable recreational benefits and contribute to our wider environmental goals.
Example: Hardwick Hall — in the summer of 2022, the rooms at Hardwick Hall became excessively hot, especially on the upper floors. The team ensured that volunteers swapped locations regularly and took more regular breaks to cope with being in the warmer rooms. The heating was also switched off, despite high relative humidity, due to rooms reaching the upper temperature limit on the conservation heating controls. A project is currently underway to look at replacing internal blinds to reduce light levels and heat absorbency of the rooms.
The Trust is considering our visitor operation carefully, to ensure that visitors and staff are protected from the worst impacts of extreme heat. We are finding, for example, that it may be necessary to adapt the way buildings are used by relocating spaces of high activity and dwell time, for example cafes, away from areas of higher heat gains. Alternatively, changing times of use, for instance, where it is feasible, opening and/or programming and working patterns may be altered to avoid the hotter middle of the day. This echoes formats of opening and working already typical in other warmer climates.
Example: Ham House — the effects of heat felt by staff and volunteers in garden spaces at Ham House were particularly acute in the walled garden, where there is very little air movement or shade. To adapt to the heat, volunteering hours and staff shifts were changed so that people came in earlier in the day (from early morning) and finished before the peak heat of the afternoon.
The most recent National Adaptation Programme, (NAP3), July 2023, says ‘tackling public health risks from overheating is a key priority for government’. While there have been updates to building regulations that recognise the need to mitigate the risk of overheating in new homes, there remains a lack of policy and direction to address overheating in existing and historic residential and non-residential buildings within the NAP, and associated policy.
This was highlighted by the Climate Change Committee’s 2023 Progress Report to Parliament (p18). More action is needed to balance government emphasis of improving thermal performance of buildings for energy efficiency and comfort in winter, (EPCs and MMES) with requirements for cooling in increased and extended periods of hotter weather. We also need recognition within our policies that traditionally built buildings perform differently to modern ones, and in some cases are better than new buildings at naturally regulating temperature. This links to a more integrated, ‘whole building’ approach as promoted by Historic England in their ‘Energy Efficiency and Historic Buildings: How to Improve Energy Efficiency’, which states that aims for energy efficiency ‘should be to understand how measures perform as part of the overall system, and to minimise unintended consequences, such as overheating, moisture problems and poor indoor air quality’ (p4).
In particular, regarding EPCs, we believe that we will not be able to attain high energy efficiency standards in our homes if we continue using the Energy Performance Certificate (EPC) in its current form. We urgently need action on EPCs to ensure they are fit for purpose and are a reliable source of information to enable a homeowner or landlord to make decisions on their property. In order to do this EPCs need to use accurate information on building performance, ensure recommendations provided take property fabric and construction into account (to avoid unintended consequences), and provide realistic installation costs and projected savings for each measure.
Currently, the planning system provides little encouragement of actively securing heat resilience measures; while there is some guidance in the National Planning Policy Framework (NPPF), this tends to focus more on energy generation from renewables. The NPPF does indicate that new development should be planned such that it avoids putting it at risk from climate change impacts and clearly this could steer policies at a local level to be more specific, but we are not aware of any which have addressed heat resilience. The NPPF does indicate in a number of places the multiple benefits that green and blue infrastructure can provide including mitigating the effects of climate change, but this could go further across a broader range of measures. Changes proposed in the Levelling Up and Regeneration Bill which would introduce National Development Management Policies may provide an opportunity to further strengthen requirements.
The introduction of design codes across England provides a significant opportunity to require new methods and approaches to development which would support the inclusion of heat resilient measures as an embedded and integrated component of all new development proposals.
The National Trust has a significant domestically-let estate. At the National Trust we underpin our approach to sustainable cooling solutions and adaptation to higher temperatures on monitoring and risk assessment. Our buildings, which were mainly constructed before 1919, are usually good at keeping cool in hotter weather, due to thermal mass, but data from our historic houses shows that some rooms reached over 36°c in the summer of 2022. Coupled with the risks from overheating during the day, night cooling can be limited in built-up environments, characteristic of the ‘urban heat island’ effect, such properties often continuing to experience the effects of overheating through the night and into the following day. The effect of higher temperatures can have considerable effect on the comfort and safety of National Trust visitors, staff and volunteers and the conservation of our collections.
In acknowledgement of the need to adapt our properties to the challenges of climate change, we have developed a climate change Hazard Map that illustrates the threat of higher temperatures. We have been able to see that all properties in regions of London and the South East and Midlands and the East of England are projected to experience increase in temperature by 2061-80 of 3.9-6.65 degrees Celsius above the 1981-2000 baseline, under high emission prediction RCP8.5. With this in mind, we have commissioned research on overheating and urban heat islands from Atkins on thresholds, impacts and potential adaptation measures. We have also recently developed targeted National Trust Adaptation Guidance on Higher Temperatures, to help guide our response to higher temperatures, at property level. This guidance is currently available online and we would be happy to share or discuss this guidance with the committee in more detail.
Building Regulations Part O (2021) addresses overheating in newly constructed domestic buildings but does not account for existing and non-domestic buildings.
The National Trust has generally always been supportive of the specific actions and results that might arise out a typical heat resilience strategy, for example, those produced in the United States[1], which might recommend actions such as increased street trees and foliage and raising awareness of and preparing for extreme heat events, hopefully leading to long-term economic, public health, aesthetic, and environmental benefits.
Many of the interventions and policy recommendations that might make up a typical heat resilience strategy, might be better suited to other existing strategies and policy documents. For example, the NPPF is the right place for recommendations on specific planning interventions, and we would like to see more references, like those that recommend that new streets are tree lined and account for “the risk of overheating from rising temperatures”.
That said, the Trust would see benefit in pulling together this suite of policy and other interventions into a single document, with a wider strategic focus towards heat resilience specifically, allowing for an “integrated and joined-up, cross-departmental approach”[2]. There is currently an identified weakness and missed opportunity within government to undertake a serious holistic approach, across both heat resilience and wider climate adaptation.
More broadly, we believe that Government need to embed climate adaptation thinking in the heart of their operations. This means a strategic cross-Government approach to addressing the risks and visioning a future that is climate adapted. The current Third National Adaptation Plan contains very few new policies or concrete actions that will deliver climate resilience. Instead, the Trust believes we need a step-change in the ambition of our approach, with national targets for climate adaptation that drive real action. We believe a heat resilience strategy needs to be a part of this wider change in approach, and one of several measures that force Government at a national and local level to integrate climate resilience into their business as usual.
[1] 04212022_Boston Heat Resilience Plan_Chapter6-Heat Resilience Strategies.pdf
[2] Policymakers must be much better prepared for heatwaves in London - Grantham Research Institute on climate change and the environment (lse.ac.uk)
Katie Ramsey
August 2023