The City of London seen from the Jubilee Bridge on a cloudy morning in March. The red spots show places in buildings that either emit heat or that are warming under the sunlight. Cars rush through the bridges and into the financial heart of the capital. Office buildings, most likely half-empty due to coronavirus restrictions, were much hotter than the surrounding areas.
The city as seen from the Jubilee Bridge. The red spots show places in buildings that either emit heat or are warming under the sun.

A Heat Camera Shows Where London Is Succeeding—and Failing—at Saving Power

An engineer takes us on a thermal tour of the city.

From Bloomberg Green + CityLab
By Laura Millan Lombraña
Thermal Images by Paul Buckingham

As anyone who’s braved crowded trains, buses, and highways to get out of the city on a sweltering summer Friday knows, the urban environment gets hot—a phenomenon known as the heat island effect. The big picture can be seen from space using satellite thermal imaging equipment, but to cool things down, we have to trace excess heat to its source. For the last 11 years, an electrical engineer in the U.K. named Paul Buckingham has been taking thermal images to persuade home- and business-owners to invest in efficiency. “I’ve become an investigator more than anything else,” he says. “What I’m finding is upsetting everyone in the construction industry.” In March he went to London on assignment for Bloomberg Green. His lens transforms the city, showing buildings, cars, and the Tube as collections of poor materials, bad insulation, and inefficient design.

Each thermal image has a scale showing the range of temperature captured, in degrees Celsius.

The train and platform of London’s Euston Station were equally hot—and almost double the temperature outside—indicating that the metro system is a major source of city heat.
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Euston station: As it is often the case in any major city’s underground transport system, temperature inside this London tube station is much higher than in the street, but it’s equally hot inside the train and on the platform. The train’s brakes and suspension, which generate energy as they move, are even hotter.
Electric car: An electric vehicle rushing in front of Harrod’s emits almost no heat, while the thermal camera detects the heat from combustion engine vehicles around it.
A Tesla whizzing past Harrod’s department store emits almost no heat, while the combustion engines around it blaze.
Ashmount Primary School in Crouch End is possibly the most energy-efficient building in this series. On a school day in March, the building appears almost perfectly isolated, with heat coming out only from an air handling unit on the ground floor. The building is covered in timber cladding, a material favored by green architects for its isolating properties, and is heated sustainably through a bio mass boiler.
Ashmount Primary School in the artsy Crouch End neighborhood is the most energy-efficient building Buckingham spotted. It appears almost perfectly insulated, with heat coming only from an air handling unit on the ground floor.
The Crystal: A beacon of sustainable building, the Crystal’s glass surfaces that remain on the shade appear blue and green. Rather than heating inefficiencies in a building that was empty when the picture was taken, the temperature detected by the thermal camera seems to be a reflection of the sun, and of heat emitted by less efficient buildings around the Crystal. It’s proof that an inefficient building doesn’t just impact air temperature, but also other structures nearby.
The glass surfaces of the Crystal, a monument to green architecture, are reflecting heat, not emitting it. Some of the heat bouncing off the Crystal (which was empty on the day this photo was taken) appears to be from nearby inhabited buildings, demonstrating the wider impact of heat inefficiency.
Victoria and Albert Museum: The 19th century stone building leaked heat on a cool morning in March even as it remains closed to the public during coronavirus restrictions. The Victorian, carved stones on its main façade hold heat successfully. But heat escapes through closed glass windows and wooden doors, seen in orange and red.
The 19th century stone building housing the Victoria & Albert Museum starkly illustrates the difference materials can make: Its carved stones remain cool, while the glass windows and wooden doors glow warm.
Ikea: One of the companies most vocal about its commitment to sustainability, Ikea’s insulation system for its store in London seems to be working. The shadings on the façade seem to be capturing the heat from the morning sun, and the inside of the building appears cool. In front of it, a double-decked bus’ engine emits heat.
Ikea is vocal in its commitment to sustainability, and the insulation on its London store seems to be following through. The shadings on the façade capture warmth from the morning sun without affecting the interior. Out front, a double-decker bus engine pumps out heat.
London Cable Car: Built in steel and metal, the cable car crossing River Thames in East London barely emits any heat and remains pretty much at ambient temperature. Only the areas that receive direct sunlight –a glass wall and the cable car—heat up. The wheels and the cables, which are running constantly, hesat up and show in dark orange or red, revealing where the movement happens even in a still image.
A cable car spanning the Thames in East London emits minimal heat. The exception is the wheels and cables, which run constantly and show up in dark orange or red.
Camden Station: London black cabs leave their engines on as they wait for passengers in front of the Camden metro station and become constant emitters of heat and air pollution.
London black cabs leave their engines on as they wait for passengers in front of the Camden metro station, becoming constant sources of heat and air pollution.
Thermal shades: the sun has warmed the metallic posts on the street, but the pavement is significantly colder in the areas shaded by the posts, highlighting the importance of shade in cities.
The sun warms metal posts on the street, while the pavement stays significantly cooler—especially the parts in the shadow of the posts, highlighting the importance of shade.
London Docks: Two swans rest on the waters of River Thames. Their bodies are at ambient temperature, and only the black stripes in their heads accumulate heat. Rivers, lakes and green areas tend to have much lower temperatures than buildings and asphalt. In cities, they help cool down surrounding areas and are essential to counter the heat island effect.
Only the black stripes on the heads of two swans resting on the Thames accumulate heat. Rivers, lakes and green areas tend to have much lower temperatures than buildings and asphalt. In cities, they help cool down surrounding areas and are essential to counter the heat island effect.
Harrod’s: The bright lights used to attract passerby’s attention toward the display windows of London’s most famous luxury department store emit much more heat than the rest of the building. Bright red windows indicate floors where staff might be working, even as Harrod’s remains closed to the public, or places where the heating hasn’t been turned off
The bright lights of the Harrod's sign emit much more heat than the rest of the building. Bright red windows indicate floors where staff might be working, even as the department store remains closed to the public.
Royal Victoria Dock: Laura Fod’s bronze ‘Bird Boy’ sculpture appears warm under the morning sun. So do the three ducks resting by it side, and the building in front of it. At the same time, the water around it looks significantly cooler.
The bronze Bird Boy sculpture appears warm under the morning sun, as do the three ducks resting by it side.

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