The UK needs to rethink how homes and workplaces are designed and operated as periods of hot weather become an increasingly important consideration for the built environment, according to CIBSE Technical Director Dr Anastasia Mylona.
Speaking on BBC Radio 4’s The World This Weekend recently, Dr Mylona discussed the implications of a changing climate for the UK’s infrastructure, highlighting the need for building design and construction practices to respond to increasingly challenging summer conditions.
The UK has traditionally designed buildings around the need to protect occupants from cold weather and retain heat during winter. However, this approach does not necessarily ensure that buildings remain comfortable and safe during periods of extreme heat.
“Traditionally in the UK, we had to deal with cold climate. So we insulate our homes and our buildings. We would try to keep them warm during the winter and remove all heat losses if possible.”
Dr Mylona explained that, because the UK has historically experienced a predominantly cool climate, consideration of summer performance and overheating has not always been given the same priority as winter energy efficiency.
“With hot weather, we don't think about as designers and occupants. We don't think about how homes and buildings perform during the summer” she said.
Designing for both winter and summer
As the UK experiences more frequent and intense periods of hot weather, designing buildings to perform well throughout the year is becoming increasingly important.
Dr Mylona identified two fundamental principles for managing heat within buildings: shading and ventilation.
The first is preventing solar radiation from entering a building in the first place. External shading can play a particularly important role in reducing solar gains and limiting the amount of heat entering a building.
“The first one is shading. So you need to stop the sun from coming into the building,” Dr Mylona explained.
She highlighted external shading as one of the most effective measures available to reduce overheating, while noting that it is not yet a typical feature of many UK buildings.
“External shading is the single most effective mitigation option solution that you put in your building to stop it overheating. But it's not something that we normally do in the UK.”
The second principle is ventilation: removing heat that has accumulated within a building and replacing it with cooler outside air where conditions allow.
“The second one is ventilation so that any heat that is accumulated in the space, it's kind of ventilated out.”
However, designing buildings for both cold winters and hot summers presents challenges. Measures that help buildings retain heat during winter can sometimes conflict with strategies needed to manage heat during summer, while established construction practices and expectations can also make it difficult to introduce new approaches.
A fundamental shift in building design
For Dr Mylona, adapting to hotter conditions requires more than simply adding cooling systems to buildings. It requires a fundamental shift in the way designers, occupants and the wider industry think about building performance.
This includes considering how buildings will perform throughout the year and incorporating passive measures that can reduce the need for mechanical cooling.
External shading, appropriate ventilation and other passive design measures can help buildings manage heat while supporting energy efficiency and occupant comfort.
The challenge is particularly important as the UK's building stock is expected to remain in use for decades. Decisions made today about the design, refurbishment and operation of buildings will therefore influence their resilience to future climate conditions.
The built environment has a critical role to play in ensuring that homes, workplaces and other buildings remain comfortable, healthy and functional as the climate changes.
As Dr Mylona concluded during the interview, adapting to hotter conditions represents a fundamental shift in the way the UK approaches building design.
“It’s a fundamental shift in the way we think.”
For CIBSE, this reinforces the importance of designing for future climate conditions and ensuring that building professionals have the knowledge and guidance required to deliver buildings that perform effectively in both winter and summer.
CIBSE continues to support the industry with evidence-based guidance, expertise and resources to help professionals address overheating risk, building performance and the wider challenges associated with climate change.
Listen to CIBSE’s contribution to the discussion on BBC Radio 4 HERE (Dr Anastasia Mylona’s interview begins at 14:39)