In a land of cold, the architecture is tested by heat

Philip Kennicott, The Post's art and architecture critic, Frank Hulley-Jones, a designer, and Laura Hynd, a photographer, traveled across the United Kingdom for this story.

Since time immemorial, this island nation has struggled against cold and damp. The challenge was to build a house in which candles didn’t flicker when the wind howled outside, and moisture didn’t gather too egregiously on cold walls of stone and brick. The dark was an issue, too, with large windows a distinctive architectural feature as this northern country became a world power, colonial empire and the inventor and supreme beneficiary of a coal-based industrial economy.

But summer hits the United Kingdom, too, and increasingly brings its own challenges. Beginning in June, successive heat waves sent temperatures soaring, in some places over 100-degrees. Authorities issued dire warnings about health, wildfires and overstressed bridges and train tracks, and the country’s built environment underwent a gut-wrenching stress test.

Now, the U.K. is heading into the dark, cold months once again, with the war in Ukraine and global inflation driving up fuel prices to the point that many fear having to make a basic choice between food and heat. Climate change is not an abstraction but felt immediately and painfully in homes — which are under ever greater scrutiny as the nation seeks solutions to the challenges of weather extremes.

“Our biggest challenge is our existing buildings,” says Julie Hirigoyen, CEO of the United Kingdom Green Building Council. “And in the U.K. our homes are some of the draftiest and leakiest across most of Europe.” But choices made to protect from the cold can also trap the heat. Many find themselves living in spaces ill-equipped for either season. There is, says Hirigoyen, “a huge piece of work to be done” when it comes to retrofitting local architecture for both hot and cold weather.

Much of this country’s housing stock was built more than a century ago, and too much of it built poorly and unsustainably. And there are enormous inequities in British housing, creating social fissures that will be exacerbated this coming winter as people deal with soaring fuel prices. But an architectural tour of this country’s houses — from grand iconic structures, like the Elizabethan Hardwick Hall to more modest Victorian Terrace homes and modern tower blocks — suggests that the lessons learned over the centuries about how to deal with the harsh realities of weather may apply today. As one advocate for making older structures more sustainable says, “Buildings are vessels and we’ve forgotten how to sail these ships.”

Late 16th century

Hardwick Hall

Architecture in a cold climate

Last summer, staff members at Hardwick Hall, a historic Elizabethan landmark in Derbyshire, were keenly aware of the excessive heat. The house, built during a period of exceptional cold known as the Little Ice Age, is a masterpiece of British architecture. With its glittering array of tall windows, it was vulnerable to the cold, but key design elements made it surprisingly efficient at managing the climate of its day.

Constructed during the “Little Ice Age,” Hardwick Hall was designed to fight the cold. Its thick, stone walls were efficient at absorbing and retaining heat.

Light came through tall, vertical windows — and Hardwick Hall had more than 150 of them, a luxury when glass was expensive.

Glass can be thermally inefficient, so some of the hall’s windows are “faux,” just glass over stone, to complete the symmetry of the design. Like this one, blocked up by a later owner, they were often placed on the cold, north side.

A long, spine wall contained fireplaces that radiated heat and warmed the wall itself.

Bathed in sunlight and heated from the spine wall, the Long Gallery was among the warmer of the grand, ceremonial rooms.

During last summer’s heat wave, the sun blasted the walls and windows of Hardwick Hall’s Long Gallery. The majestic, upper-floor chamber that runs the length of the house heated up well beyond the comfort zone. But that was exactly how the building was meant to behave.

Bess of Hardwick, the formidable widow who built this late-16th century house (and likely played a key role in its design along with architect Robert Smythson), took her exercise in the East-facing, sun-drenched Long Gallery when the weather was cold, wet or both. The heat gain through its enormously tall windows, which line the length of the room, was intentional.

Hardwick Hall is renowned for its many windows, majestic public spaces — including the Long Gallery — and rich collection of art, tapestries and original Elizabethan decoration. Among its most thermally stable rooms was the smaller-scaled Withdrawing Chamber, where Bess of Hardwick and subsequent owners would retreat for greater comfort.

Hardwick Hall is one of the best-studied and best-preserved of the Elizabethan “prodigy houses,” built to reflect the splendor of wealth and the aspirations of ambitious aristocrats jockeying for power in the turmoil of Tudor politics. Ranald Lawrence, professor at the School of Architecture at the University of Liverpool and Dean Hawkes, emeritus professor at Cardiff University and an emeritus fellow of Darwin College at the University of Cambridge, have explored the thermal performance of the hall, and how that affected daily life. What they found was a structure that was remarkably efficient at keeping temperatures tolerably comfortable through most of the year.

Critical to this was the sheer mass of the building, and the spine wall, with its fireplaces and exposure to the sun. “The sun sets and it’s giving out that heat and that energy into the evening and into the night,” says Lawrence.

Thermal imaging shows temperature differentials between the new and old glass. (Thermal photo by Frank Hulley-Jones/The Washington Post)

Hardwick Hall was still cold in the winter but its inhabitants understood how the house worked thermally. Bess retreated to her smaller, warmer, more thermally stable rooms for greater comfort when not entertaining. Social adaptation to climate — including how one dressed, where one sat and the degree of comfort one expected — were factored into the house’s basic design. But these lessons were often lost or forgotten in later iterations of British architecture.

19th century

Terrace House

Coal democratizes architecture

By the 17th century, coal was transforming the economy and architecture of the British Isles. It was the essential fuel of the Victorian terrace house, among the most common housing types in the United Kingdom. Tens of thousands of them were built in cities across the country as industrial and trade wealth exploded in the 19th century. Some were grand and capacious, others scaled to the rising middle class, and many of them, like the workers’ housing of Liverpool, were small, cookie-cutter structures built to minimum, basic standards established by law.

This is a typical 19th century terrace house. Shared walls on two sides offer effective insulation.

Terrace houses were designed with smaller rooms to contain heat.

Abundant coal made glass cheaper, and sash windows — with movable upper and lower panes — became standard even in modest homes.

Small coal fireplaces were distributed throughout the house.

Separated from the fireplaces, the narrow long hall was a chilly, transitional space.

In recent decades, owners often installed more efficient windows and added more glass — skylights and glazed extensions— to bring in light.

Removing walls to have a modern open space is another common retrofit.

Some renovations, including overhead insulation, that make a house more airtight can trap warmth during prolonged summer heat.

These modest homes had features that would have been a luxury in the age of Bess of Hardwick. Brick and glass were used long before the rise of the coal economy, but they weren’t standard, or accessible to most homeowners. Coal changed not only what homes were made of — it enabled the large-scale, cheap production of brick and glass — but also how people defined basic comfort.

“It is the biggest transition in the history of our species, with the possible exception of starting to use fire at all in the first place,” says Barnabas Calder, author of the groundbreaking study “Architecture: From Prehistory to Climate Emergency.” Fireplaces had to be redesigned for coal, smaller, and more efficient, and could now be distributed throughout the house, warming a sequence of smaller rooms that contained heat more efficiently. Brick, which also requires substantial amounts of energy to produce, became affordable. And glass, too, was accessible to ordinary people. “Coal affects the way you can achieve comfort conditions in a building, and it is a very affordable way of producing a significant amount of warmth, which allows for bigger windows. Even more significant is that it opens up a series of new building materials.”

Coal transformed architecture and housing in the 19th century. New neighborhoods of working-class housing were built all across the United Kingdom, including the modest houses of Cairn Street, Liverpool, where coal hole covers still dot sidewalks. Access to the coal was through the basement. Rooms were small and the hallway was often cold, creating different temperature zones and comfort levels. Many of these houses have been abandoned or demolished.

Key to the thermal performance of the terrace house, especially during the warmer months, was the sash window, an impressive machine. When functioning properly, counterweights balance the weight of the glass and wood frames, and it can be opened from both the top, the bottom, or both. When both the top and bottom are opened, a natural flow of hot air out and cooler air in develops, which also helps clear a room of stale smells and smoke. The carefully weighted mechanism allowed subtle regulation of the aperture, and unlike casement windows, they weren’t susceptible to sudden blasts of wind shearing them from their frames.

The Liverpool home of Hazel Tilley, a retired hospital social worker, is a two-floor house on Cairns Street, built in the second half of the 19th century to serve the city’s working class. Homes like this one — two rooms downstairs, two (and sometimes three) bedrooms upstairs, with a side hall and a kitchen to the rear — are ubiquitous in the United Kingdom.

Built with solid walls, they lack the cavity space that makes it easier to insulate new construction. Their existing heating systems are often decades old, and inefficient. And adding new systems — wires, pipes, heating and cooling elements — can be complicated.

In the age of climate change, they also present a policy challenge: They will never be as efficient as a well-designed modern house but demolishing and replacing them would only pump more carbon into the atmosphere. The challenge is to learn how to operate them for maximum thermal efficiency.

Unlike some of her neighbors, who have removed walls and opened the living space, Tilley kept her house in its original configuration. “I like it,” she says. “It was easier to heat small rooms.”

In a typical terrace house, the hall may be chilly but the small parlors have coal fireplaces. When the doors to these small rooms are closed, they can be heated to a relative degree of comfort. With a few tweaks, Tilley’s house performed well during the heat wave, too, she says. “Closing curtains at the front, but not the back, and opening the back windows — it was fairly easy to keep cool,” she says.

Owners of these homes often don’t have the resources to improve them. And when they do, they may be more interested in adapting them to modern lifestyles. And thermal retrofits can have unforeseen consequences: Tweaking a house toward greater warmth in the winter may make it more uncomfortable in the summer. And vice versa: More open plans can improve ventilation in the summer while making spaces harder to heat during colder months. A more immediate and less expensive solution would be to live in them more like a Victorian: Changing one’s dress, using wingback chairs to create zones of personal warmth, and accustoming oneself to a range of microclimates — like cold hallways — throughout the house.

20th century

Tower block

The age of “plug in” architecture

The goal of many renovations is to make older houses perform more like the fantasy of climate and comfort embedded in the modern tower block. For decades beginning in the middle of the last century, Britain responded to its postwar housing crisis by building concrete high rises. Whole neighborhoods of houses like the one Tilley lives in were razed, to create more “modern,” hygienic and affordable homes.

Tower blocks with flats like this promised modern convenience but were beset by engineering and sometimes social problems.

Electrical lighting meant flats could extend deep into a building’s interior, with fewer windows.

Windows on only one side limited ventilation, which could lead to overheating.

Poorly manufactured windows made apartments vulnerable to both hot and cold spells.

Flats were fitted into the larger system of the tower, highly dependent on ready supplies of cheap energy. Retrofitting them is among the U.K.'s most expensive housing challenges.

Electricity generated by coal-fired plants made these innovations possible, running the elevators and bringing light and power into the depths of modern flats that often had windows only one side. Buildings functioned more like machines than the “vessels” of the past. When you plugged them in, they were meant to be comfortable throughout the structure.

In Chalcots estate in London a ground floor communal elevator lobby has a notice board where a resident points out safety regulations for windows not mentioned by architects.

Mid-century tower blocks proliferated in cities across this country after the Second World War. Architecturally, they embodied an egalitarian social vision of clean, safe, comfortable housing for the masses, at a time when many people still lived in decrepit terrace homes with minimal plumbing. But they were built at a time when energy supplies were relatively cheap and abundant, which has led to decades of design problems, including ones that became urgent during last summer’s heat wave.

When the temperatures spiked, residents of the Chalcots estate, a campus of five high-rise towers in north London, built in the late 1960s, found the heat unbearable. Anthony J. Royle, who owns a west-facing flat on the 18th floor, felt the heat gather through the day, and continue radiating into the flat at night. Residents complained that some elevators stopped working during the heat wave, underscoring how vulnerable these buildings are when their systems are stressed.

Solutions to the problem of overheating are fewer and more complicated in tower blocks. Air conditioning would require a prohibitively expensive retrofit, and only contribute to the greenhouse gases that are causing the heat waves. Better windows help, but seemingly small changes to windows — including their size and how they open — can have big impacts on residents. At Chalcots, residents, including Royle, are concerned about a new window system that would be larger, and with more limited options for opening and airing out the apartments. More glass may seem like an architectural amenity — especially if you can afford air conditioning — but last summer’s heat has left many concerned about solar heat gain.

“The impact of windows with 30 percent more glass won’t be balanced by the type of glass,” says Royle, referring to the more thermally efficient panes. “People don’t want them to overheat, as they do at the moment.”

Tower block residents are heavily dependent on each other and local authorities to find solutions to their architectural problems. And schemes to retrofit them — for fire safety or better performance in the cold months — often seem to lag behind current crises, like the disruption of last summer’s heat waves.

Hotter summers, and the possible energy crisis this winter, are forcing the United Kingdom to confront some hard architectural realities. At Hardwick, senior collections and house officer Elena Williams says stewards of the building are now earnestly considering how to defend against heat, while preserving the Hall’s priceless collection of art, tapestries and furnishings. In Liverpool, Tilley had an energy audit performed on her house, and explored adding external insulation to the back wall, where it wouldn’t detract from the historic street facade, but the cost was too great. In the lobby at Chalcots, someone has taped a National Health Service flier to the bulletin board, warning about the health danger of heat waves.

But beyond retrofitting buildings, there’s also learning how to live in them, and live in them as they were meant to be lived in. At Hardwick Hall, the most comfortable rooms are the least grand, confined to one of the warmest corners of the house, with fewer and smaller windows. That’s where Bess lived when temperatures plunged. Victorian architecture teaches us the importance of “transitional” zones, says Lawrence, from Liverpool. Research suggests that buildings with a variety of temperature zones — like the cold hallway and snug parlors of Tilley’s house — acclimatize us to find a wider range of temperatures comfortable.

Architecture also embodies character, including national character. Hardwick Hall is one of the glories of British architecture; the Victorian Terrace house carries deep cultural memories (and myths) of domestic life and aspiration; and the mid-century tower block retains a fading promise of equal comfort and dignity for people of all classes. Retaining the best of these homes while adapting for climate change won’t be easy.

But along with all the embodied carbon in this country’s houses, there is an embodied wisdom, if you know how to read it. Learning how to “sail these vessels” will require massive cultural change, which will impact some people more profoundly than others. Cultural change is hard, and painful, but it’s also free and carbon neutral.

About this story

To create the 3D models of the terrace house and the tower block, Post reporters took measurements of a typical terrace house on Cairns Street, Liverpool, and a two-bedroom corner apartment in London’s Chalcots Estate.

Editing by Monica Ulmanu and Moira Haney.