The UK has entered another heatwave during an unusually hot few months that has brought a new headache for occupiers and landlords. How can buildings be adapted to more extreme heat without the need to ramp up air conditioning and other initiatives that in turn increase energy costs and emissions?
There are a lot of countries that experience hotter weather that can provide transferrable solutions, not least close to home in Southern Europe. But the UK does have specific issues to do with legacy buildings and a workforce that is not used to such extended periods of plus 30 degree heat to contend with.
The first thing to say is it's definitely a time to go to the office or the mall rather than languish in the poorly air-conditioned homes that are the common experience of UK residents. But ultimately, the issue is still an economic one. Research by the International Labour Organisation in its Working on a Warmer Planet research found that there is a 50% drop in productivity when temperatures lift above 34C. Climate risk analyst group Climate X published research recently estimating that loss of worker productivity due to overheated buildings in London could reach £203.4 million per year by 2030. It estimates that a lack of priority given to the installation of air conditioning in commercial and residential buildings means London is particularly vulnerable to rising temperatures and says that upgrading high-priority buildings around the capital would cost £440 million.
With London recording an all-time June record of 36.4C, and such levels seemingly becoming the future norm across the UK in summer, developers are focusing on creating cool, comfortable places to work in that don't create problems for the environment.
The first thing to say is respective governments have been waking up to the issue with legislation, but with a focus on residential. In 2021, Building Regulations Part O were introduced to address the growing problem of overheating in homes. The regulations have provide measurable guidance to limit unwanted solar gain during summer periods and provide occupants with adequate means of removing excess heat from indoors. But the regulations only apply to new buildings and commercial property is exempt.
Jeremy Lacey, development director at Quadrant Estates, is working on solutions across the developer and investor's portfolio and says the over-riding issue is heating, ventilation and air conditioning (HVAC) systems are designed to specific set points for controlling temperatures in buildings in the UK which now need to move on.
"Where we live it's getting hotter clearly. On a development project I worked on in Knightsbridge for instance, residents who rented private apartments from the Middle East and some parts of America are used to very different systems to the conventional HVAC that are commonplace across the UK. They just did not understand why you can only ever get the apartment air conditioning set below 19 degrees when the outside temperature is close to 40 degrees Celsius. The natural expectation is for the air conditioning to come on and be like an ice box and is the norm in countries with extreme heat climates. The whole design process needs to move on to capture these periods of extended heat we are experiencing in the UK."
Lacey explains that the design criteria for UK buildings is based on set points across a range, so the cooling load assumes an outside temperature of 20-30 degrees Celsius and the output of the system will provide an internal temperate of 20 degrees plus or minus 4 degrees.
"The set points also consider the fabric of the building, including glazing, which all feeds into the thermal model. Similar principles apply to the winter. It is a byproduct of design practice over years and years and it is important occupiers understand the nuances.”
That said, Lacey says many things can be done to work around this.
"You need to change the design parameters at the outset. We are looking at a building where we are carrying out a major retrofit in London and as we are seeing the weather is getting up close to 40 degrees for lengthy spells, we are looking at what can be done to accommodate this seasonal change."
One area is providing more chillers as they enable an increased cooling load, facilitated by the distribution ductwork, Lacey says.
"New developments are generally all electric now, and there are more buildings with air source and ground source heat pumps than ever before. Developers are working on the integration with Building Management Systems (BMS) to monitor consumption and assume the plant is running efficiently."
Lacey says the key is to find a sweet spot temperature wise. "We have all been in buildings where one person is freezing and another is too hot." Zoning and control systems can deal with this, but only so far, he says.
Mark Caldwell, asset manager at AshbyCapital, says extreme heat is becoming an increasingly important consideration for landlords, and that means his business is taking a proactive approach to monitoring and managing buildings during warmer periods.
"We use our building management systems to track performance in real time and can implement measures such as pre-cooling buildings ahead of the working day, adjusting cooling settings where necessary, and responding quickly to maintenance issues that may affect occupier comfort."
Dane Matthews, head of UK residential asset management at CBRE Investment Management, says climate change has been a key driver in decision making when it focuses on developing affordable homes. "We believe protecting long-term asset value means preparing our portfolios for extreme heat."
At one of the group's largest assets, the 294-home Florence at Wood Wharf on the Canary Wharf estate which will be handed over this year, Matthews says CBRE IM has committed to ensuring that the homes provided allow residents to remain comfortable, even in periods of significant heat. “For this development planning approval predated newer overheating regulations, so we went above and beyond, and worked closely with our development partner, Canary Wharf Group. We adopted Part O standards across the building by combining passive shading, fabric insulation, and efficient cooling, so the asset now delivers high-quality, heat-resilient affordable homes whilst also keeping running costs low."
Green and blue introductions
Also more and more in focus is providing greening in buildings and around them to create the kind of shade and protection that cities like Seville have used for centuries to keep cool.
Lacey says: "There is obviously more and more focus on providing urban greening on facades and rooftops to provide further mitigation to heat gain whilst improving the urban greening factor."
Sophie Goddard, managing director ESG at CWG, says that as a custodian of Canary Wharf's 128-acre mixed-use district, the group has been focused for some time on embedding climate resilience into the fabric of the place itself, not just individual buildings.
Goddard says that by addressing urban heat across the spaces between buildings, what she terms "blue and green infrastructure" can deliver "scalable, cost-effective benefits that enhance resilience while improving the experience of our entire community".
Goddard says the regeneration of Canary Wharf's Eden Dock, which was delivered in partnership with the Eden Project, was designed not only to create a welcoming and engaging place, but also to strengthen the longer term resilience of the estate and improve the comfort of those who use it.
"With 42 trees and more than 70 resilient plant species which provide shade and evaporative cooling, it delivers a 10% reduction in the urban heat island effect. The planting works alongside natural paving and FSC-certified timber to replace dark, heat-absorbing hard surfaces, whilst the water surface itself provides further evaporative cooling."
She adds that Eden Dock forms the cornerstone of what she terms Canary Wharf's blue and green spine. "Running directly down the central line of the district, the spine connects parks, gardens, waterside spaces, living walls and performance areas, creating continuous cooling corridors through a dense urban environment." She says the interventions are both replicable and scalable and as such should offer "valuable lessons for cities around the world adapting to a warming climate".
Goddard points out that this is neither an accidental nor decorative addition. "They are examples of climate resilience intentionally designed into the urban landscape to reduce temperatures, regulate heat, improve air quality and enhance biodiversity. As cities around the world face summers that would once have seemed unimaginable, green and blue public spaces are no longer a nice-to-have. They are essential infrastructure for creating resilient, liveable places."
At Grosvenor Square, where the Duke of Westminster's property company has been investing in a massive reworking to improve climate resilience, there has been a focus on introducing planting that is better adapted to warmer weather. Ed Green, Grosvenor Property UK’s sustainability director, has said a conscious decision has been made to bring in some species that are more used to living in more continental climates to increase resilience and the flowering window. That has meant putting in a mix of native species and non-natives to improve hardiness and drought resistance.
Every little helps
Businesses are are also focusing on how staff can be helped to have a cooler day through tweaks to working hours and practices.
Mark Caldwell, asset manager at AshbyCapital, says the group's portfolio is made up of modern Grade A offices that have been designed to perform well in the latest conditions. "All our buildings have remained comfortable and resilient despite higher temperatures." But he says that alongside the operational measures, AshbyCapital has also introduced some "lighter-touch initiatives" for occupiers, including complimentary ice creams in reception at The JJ Mack Building and One Bartholomew during the hottest spells.
Lacey says businesses are finding different working hours for staff can help. "Staff coming in earlier or later to miss the peak times of the heat; also the more bodies there are in the office at one time the more heat is generated. However, these ideas are more management initiatives and nibbling around the edges. It won't work around the trading floor for instance. Here it is about changing the design criteria. How can you build in more resilience? It is about more cooling load generated by the chillers. This requires additional space for plant and riser provision.”
One increasingly popular solution Lacey says is below floor air conditioning systems. "That is clever in that it gets heat or cooling to where people sit. It is not coming from the ceiling and working its way down and it leaves a clean ceiling from an architectural perspective."
The issue is also making developers review what a building will need to be like in years to come, given the country appears to be getting hotter.
"In terms of the design process it is a very relevant topic," says Lacey. "If a fit-out is going to last for 25 years what does it need to look like now given how the temperatures are changing? Tenants want to know about this more and more. Partly it is about educating to say this is the specification that you have signed up to. You can put in zoning parameters and controls where you can have infrastructure to make some of the space independent of the main office floor. The design has to evolve with the climate change and be forward looking.”
In terms of the impact of making buildings cooler on the environment Lacey says harmful emissions are not such a big problem in newer developments. "You have seen a lot of companies focused on degassing focused on decarb works getting rid of the old boilers all over London."
But there are going to be a lot of so-called stranded assets across all sectors. And not just in real estate.
"It is an opportunity too. The tube is really interesting," says Lacey. "Before Quadrant I worked with TfL on the Piccadilly Line and a deep new tube line for London. New trains run faster and brake harder and when they brake they generate more heat and needed to be. It was obtained through section 106 agreements on developments. A big plant room was developed above infrastructure with a massive Mechanical, Electrical, and Plumbing arrangement and heat rejection units on the roof."