As anyone who drowns in the current heat wave in the UK can attest, the country’s housing stock is sadly unsuitable for heat.
Much of it is outdated, dating back to a time when the priorities were to protect from the cold and rain. However, most newly built properties are unprepared for expert predictions that by the middle of the century, temperatures will be at the level of the 2018 summer highs every two years.
The climate change committee warned in a report last year that since 2016 more than 570,000 homes had been built that were not resistant to high temperatures, nor were 1.5 m more to be built over the five years. next.
Government councilors accused ministers of failing to act to protect people from rising temperatures that “could even leave many existing and new homes uninhabitable”.
The problem is deadly serious as vulnerable people struggle to stay cool in their own beds. The committee noted that the 2020 heat wave in England killed more than 2,500 people and warns that the number of heat-related deaths could triple by 2050.
Heat not only poses a threat to life, but also to the structural integrity of buildings, causing the walls to crack. In 2018, the UK’s hottest summer so far along with 1976, 2003 and 2006, there was an increase in subsidence as the ground floor of the buildings dried up and contracted, with more of 10,000 households who filed insurance claims worth £ 64 million in just three months.
Critics accuse housing builders, property developers and the government of being slow to respond. “The housing industry is quite traditional and going out of style when it comes to adapting and there are a lot of challenges we have to face around zero carbon and the future,” says James Knight, of the consultancy of design and engineering Arcadis.
So how can industry and the country respond to the growing threat posed by high temperatures?
Rehabilitation of old properties
The most obvious measure to mitigate heat is air conditioning, but it is prohibitive in terms of installation and operating costs, and works inefficiently in old homes with drafts. Energy-consuming systems also increase emissions, fueling global warming and worsening the overall problem.
Closing the shutters of older homes, such as this blue-painted house on Portobello Road in west London, is an effective way to avoid the sun. Photography: June Green / Alamy
Experts suggest the UK should learn from countries where extreme heat is more common, where houses have motorized blinds or shutters to prevent the sun and white surfaces to reflect heat. Knight points out that around the Mediterranean “people leave their houses closed all day, with the windows open behind them. How many of us leave the curtains closed on the south- and west-facing windows when we go to work on a sunny day?
Similar “passive measures” that require minimal use of energy and fuel to cool homes include improved natural ventilation and increased insulation, which has the dual advantage of reducing energy bills in the home. winter.
Design the heat
There are even more effective measures that home builders can introduce in the planning and construction stage: making sure the house and windows are oriented and positioned to limit exposure to direct sunlight; glass reduction; add shady trees and plants; and install an air heat pump, which can be used to cool a home and heat it.
Other cooling features include windbreaks, ceiling-mounted devices inspired by Persian architecture that use wind to propel cool breezes into a room and expel stale air, and solar fireplaces – tall structures with a dark surface designed to absorb radiation solar, creating an ascending column. of heated air which in turn maintains the flow of a ventilation system.
The most advanced example of this principle is the “passive house,” an airtight, highly insulated building that relies almost entirely on passive measures such as insolation, shade, and ventilation to ensure a constant temperature. They often feature a ventilation unit in the attic with two air collectors: one for fresh outside air and another for warm indoor air, which circulate around the house to maintain a uniform temperature.
“A passive house is the best solution where there is a natural flow of air,” says Bob Ward, vice president of the London Climate Change Partnership. “It should become the guide on how to build for zero carbon and overheating.”
Barratt’s Zed House, on the campus of the University of Salford, Manchester, is a pilot project testing technologies and features to achieve its zero carbon goal by 2030. Photo: Barratt Developments
Meanwhile, Barratt, Britain’s largest housing builder, is testing the Zed House, a zero-carbon concept house built in collaboration with 40 industry partners and Salford University. It has an air heat pump and 95 sensors to collect data in the home, including air quality. Barratt says the pilot is the first step in achieving its promise that all of its new homes will be zero carbon by 2030.
What about larger buildings?
Heat is not just a problem for domestic buildings: too many offices still depend on energy-consuming air conditioning and have large glass facades. “Huge glass buildings aren’t a good idea, this is a greenhouse,” Ward says. “You have to design the glass in a way that avoids the sun.” There is now a growing trend for the installation of shutter windows in commercial buildings: parallel glass sheets in frames that can be tilted to open or close to improve ventilation.
Again, the countries of Europe are leading the way. The Edge, a state-of-the-art office building built in Amsterdam for Deloitte in 2014, has been presented as an example of how to reimagine workspaces. It deploys dynamic windows, automatic blinds, solar panels on the south side to prevent direct sunlight, underground thermal energy storage pumps to pump hot or cold water in or out of the building, and 28,000 sensors that track the movement, lighting levels, humidity and temperature. .
What is the government doing?
So far, the UK’s focus on building efficiency has focused on improving homes with airflow, especially in light of high energy bills, but last year the government went add for the first time a section on overheating to building standards, Part O, which arrived. in force last month. It urges homebuilders to take reasonable steps to limit solar gains in the summer and “provide a suitable means to remove heat from the indoor environment.”
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However, the housing construction industry is not happy with the new rules, complaining that they could force projects already approved to return to the drawing board. Stewart Baseley, executive chairman of the Federation of Home Builders, wrote to the government in early June to complain that “new regulations are fraught with impracticability and may require tens of thousands of licensed homes to return through the process. planning”.
And what does Ward think about part O? “It should help though who knows how well it will be implemented,” he says.