The world experienced its three hottest days ever in July with the 22nd now standing as the hottest day the planet has ever seen with a global average surface temperature of 17.16°C.
Global economies are also suffering from something economists call ‘Heatflation’ – the definition of a period when extreme heat leads to rising food prices. Heatwaves are damaging and destroying crops around the world, which is a major threat to food security, and of course, it is the most vulnerable societies that are hit hardest.
With the World Health Organization (WHO) calculating that nearly half a million heat-related deaths occur globally every year already, the long-term implications of all this is truly alarming.
For the UK, scientists predict we will be 2°C hotter by the end of the century than we were in 2020. At that temperature, 90% of British homes would be so hot as to be almost uninhabitable, according to the government’s advisory Climate Change Committee. It already believes 20% of UK homes are overheating every year, even during relatively cool summers.
UK estate agents are, unsurprisingly, reporting an increase in demand for homes with air conditioning. 36% of the agents who responded to a survey carried out by the insurer Direct Line also said air conditioning was already affecting property prices with cooler homes attracting a premium.
Heat stress
Maria Lawrence, Direct Line’s product manager said that being able “to reduce heat stress is attractive for homeowners as it can impact physical and mental wellbeing”.
And across the pond, California is leading the way with new legislation that puts a legal limit on how hot it is allowed to be in workplaces. The Indoor Heat Illness Prevention rule restricts indoor temperatures to 27°C in a wide range of work settings in a bid to protect the health and well-being of millions of people.
So, how are we tackling this growing problem?
Revisions to Part O of the UK’s Building Regulations were introduced in 2022 to tighten up standards of temperature control in buildings. However, research commissioned by Zehnder Group UK found that many building services professionals were not familiar with it. Almost half (46%) said they understood the theory behind the regulation but were unsure how to put it into practice. 19% said they didn’t understand it at all.
Zehnder’s Jason Bennett pointed out that the push for more energy efficient buildings had led to greater use of “lightweight structural materials that are notorious for solar gains and lack thermal mass”.
Ironically, this means the money that might have been saved on energy was having to be spent on additional cooling measures – particularly where large amounts of glazing was also being used.
“Whilst improved energy efficiency must continue to be a priority, the future has to be about cooling solutions to ensure comfort and improved health for building occupants,” he said.
While nobody is arguing about the importance of making our buildings more climate resilient or about the impact on general health and well-being of overheating, poor indoor air quality, and inadequate ventilation, it remains a relatively low priority for project designers. Most still place energy efficiency and cost concerns above an issue that threatens to dwarf all other built environment-related problems.
In a recent report: Heat resilience and sustainable cooling the Environmental Audit Committee (EAC), which advises government, said that both physical and mental health are affected by rising temperatures with suicide risk believed to be twice as high when the temperature reaches 32°C compared with 22°C.
The committee of MPs also said high temperatures cost the UK economy £60bn a year due to work-related accidents and lack of sleep. It said more than 4.6 million homes in England experience summertime overheating.
The challenge highlighted in the Zehnder report puts a whole new complexion on the debate between retrofit and rebuild on the road to net zero. With the need to retrofit both residential and commercial buildings to improve energy efficiency already established as part of the UK’s net zero ambitions, this cannot be done at the expense of tackling overheating – and the quality of the indoor environment more generally.
Passive cooling measures, such as green roofs and solar shading, can mitigate some of the problem and would require no additional energy input, but similarly efforts to decarbonise heat and improve ventilation for health and well-being must be addressed simultaneously.
Intelligent solutions
For example, improving building airtightness should not lead to additional overheating problems so long as the ventilation and cooling measures are designed alongside. In fact, the opposite is true as better building fabric with intelligent ventilation solutions makes it easier to control indoor temperatures and reduce other problems such as condensation and mould.
The missing part of the equation is a mindset that tackles retrofitting buildings in a holistic way. Part O, and other best practice approaches to improving indoor environments, require joined up thinking that considers the building as a complete interlinked system – not a series of bolted together components.
For example, linking filtration, purification and air flow technologies with digital monitoring and control allows building managers to fine tune conditions without pushing up their energy costs. Improving building airtightness in tandem with adequate ventilation and cooling measures will also help to tackle the growing IAQ problems while fending off overheating and heat losses at the same time.
Unfortunately, holistic engineering solutions are not the norm when it comes to organising building services contracts. So, the whole approach to packaging work and tendering needs to be streamlined too. Yet, the industry does not lack motivation to get this right.
Construction is a strategic industry which has developed over time to minimise capital costs and prioritises making a return on investment over quality and performance. However, buildings should be designed for the wider benefit of society – not as financial instruments.
The new Labour government has made housebuilding a priority, but if this leads to a whole generation of new, low-quality homes the NHS will end up footing the bill while housebuilders’ shareholders pocket their dividends.
The Building Safety Act is both an opportunity and a threat. Emerging in the wake of the Grenfell Tragedy, it is firmly focused on improving the built environment for all, but by making safety the ‘critical path’ it threatens to (unintentionally) produce safe buildings that are a health and wellbeing nightmare.
We have seen this before in the case of new homes that were fitted with mechanical ventilation with heat recovery (MVHR) systems. These represented a neat engineering solution but made the crucial error of not considering the way people want to live i.e. having the ability to open windows, control their environment etc. Many MVHR systems were turned off by residents because they were noisy, and thousands were incorrectly installed by non-experts and/or never maintained.
As a result, a well-intentioned solution for supporting energy efficient homes with good quality ventilation ended up creating unhealthy living conditions, proving that engineering can address our society’s big problems, but only if we join up all the dots.
Building services firms can respond to this challenge by drawing on their own expertise and experience, but also by taking advantage of the wide range of technical guidance and support available. For example, BESA’s Indoor Air Quality group has produced a series of guides to help create strategies for improving building ventilation, tackling mould and damp, and explaining the importance of air filtration to clients.
The Association provides a wide range of technical guides and best practice specifications covering the range of ventilation and air conditioning solutions needed to get on top of our overheating crisis. We also have a range of webinars and podcasts that are available to view online which offer further insight into this issue.
We have just had another mild and wet winter, our summers are getting hotter (although often windier and wetter too), and people are spending more time in unhealthy indoor environments. This is another example of why our industry is so important and why it offers careers for people keen to make a difference – people interested in becoming the ‘good guys’ of engineering determined to design and implement a better world.