The coronavirus pandemic has revived interest in the role design has played fighting infectious diseases. Most famously, the trailblazing modern architecture of the early 20th century — open to nature and filled with light and air, as practiced by designers such as Alvar Aalto and Richard Neutra — reflected au courant ideas about health and wellness, especially in combating the scourge of tuberculosis (which also influenced bathroom design).
The battle against pathogens reshaped the inner working of buildings, too. Take that familiar annoyance for New Yorkers: the clanky radiator that overheats apartments even on the coldest days of the year. It turns out that the prodigious output of steam-heated buildings is the direct result of theories of infection control that were enlisted in the battle against the great global pandemic of 1918 and 1919.
The Spanish Influenza, which caused just over 20,000 deaths in New York City alone, “changed heating once and for all.” That’s according to Dan Holohan, a retired writer, consultant, and researcher with extensive knowledge of heating systems and steam heating. (Among his many tomes on the topic: The Lost Art of Steam Heating, from 1992.) Most radiator systems appeared in major American cities like New York City in the first third of the 20th century. This golden age of steam heat didn’t merely coincide with that pandemic: Beliefs about how to fight airborne illness influenced the design of heating systems, and created a persistent pain point for those who’ve cohabitated with a cranky old radiator. More fromIs New York’s New Subway Map a ‘Geographical Mess’?Here Are the Local Ballot Measures That Passed and FailedThe High Cost of Locking Down D.C. for Election WeekAt the City Level, Progressives Flex New Power
Health officials thought (correctly) that fresh air would ward off airborne diseases; then as now, cities rushed to move activities outdoors, from schools to courtrooms. When winter came, the need for fresh air didn’t abate. According to Holohan’s research, the Board of Health in New York City ordered that windows should remain open to provide ventilation, even in cold weather. In response, engineers began devising heating systems with this extreme use case in mind. Steam heating and radiators were designed to heat buildings on the coldest day of the year with all the windows open. Anybody who’s thrown their windows open in January, when their apartment is stifling, is, in an odd way, replicating what engineers hoped would happen a century ago.
The memories of the flu pandemic lingered. Engineering books from the 1920s often mentioned this need to design heating systems, notably the boilers and radiators, to operate with all windows open, a requirement of the “fresh air movement,” Holohan says. This health crusade, which has its roots in the post-Civil War era, saw fresh air as a necessity for good health; adherents believed that rooms with closed windows and tight airflow meant that others would breathe in your vapors and catch disease. The theory originated before modern germ theory, at a time when tuberculosis was a significant health threat. “They called unventilated air the ‘national poison,’” Holohan says.
A key proponent of the idea was Lewis Leeds, a health inspector for Union Army field hospitals who came to the conclusion that “vitiated,” or spoiled, air was the cause of the many diseases. The “spent breath” of the occupants of poorly ventilated homes contributed to 40% of the deaths in the country, he claimed, and often said “man’s own breath is his greatest enemy.” He would spend decades promoting the cause, designing ventilation schemes for buildings, penning a 1869 book, Leeds on Ventilation, and lecturing across the country. He explained his ideas with the aid of a “magic lantern” projector — think old-timey Powerpoint presentations. He’d show slides of a family in their drawing room, then add a slide showing red air coming out of the father’s mouth. The child crawling on the floor would eventually fall over. It “scared people to death,” Holohan says.
Leeds was joined in his fervent ventilation campaign by author Harriet Beecher Stowe, of Uncle Tom’s Cabin fame. With her sister, Catherine, Stowe would coauthor a 1869 book, The American Woman’s Home, that claimed “tight sleeping-rooms, and close, air-tight stoves, are now starving and poisoning more than one half of this nation.” It also introduced terrifying scenarios to shock American readers into action, such as this passage about the impact of vitiated air on a child:
Little Jim, who, fresh from his afternoon’s ramble in the fields, last evening said his prayers dutifully, and lay down to sleep in a most Christian frame, this morning sits up in bed with his hair bristling with crossness, strikes at his nurse, and declares he won’t say his prayers—that he don’t want to be good. The simple difference is, that the child, having slept in a close box of a room, his brain all night fed by poison, is in a mild state of moral insanity.
These ideas would become more formally accepted by architects and engineers during the beginning years of the 20th century. The 1901 New York State Tenement House Act mandated that every room have an outdoor facing window. New York City Health Commissioner Royal Copeland, who, as a U.S. senator in the 1920s proposed redesigning the Senate Chamber to deal with deadly, stale air, would praise the tenement laws as having a significant impact during the flu pandemic.
By the time the Spanish Flu hit, the maxims of the fresh air movement had become popular enough to impact building designs. The toll of the pandemic solidified this thinking, says Holohan. Having robust steam boilers that could keep apartments and dwellings comfortable with open windows became standard in New York City, as well as other northern cities in cold climates, such as Detroit, Chicago, Denver, Boston and Philadelphia.
The pandemic abated in 1920 but these standards had become locked into place. The architecture firm KPF found that nearly 75% of Manhattan’s existing square footage was built between 1900 and 1930. And since steam heat systems are incredibly durable, they’ve lasted for generations.
In the ensuing decades, shifts in building practice and fuel usage made the problem of over-indexed steam heat worse. The type of fuel used to heat the steam boilers changed, from coal to heating oil to natural gas, and during the changeover, Holohan says, they didn’t properly resize boilers or systematically change design standards to account for the changing power source; replacement boilers were kept big to err on the side of caution. Better windows, especially double-pane varieties, would provide the benefit of better insulation and less heat loss, but only served to lock in the impact of overly aggressive radiators. (If you own an old radiator-equipped house, you might have noticed how overpoweringly effective they can be after you replace leaky older windows with more well-insulated modern replacements.)
By the 1930s, Holohan says, a few common remedies to mitigate excessive radiator heat came into practice that last to this day. Researchers at the National Bureau of Standards found that if radiators were painted with a special kind of bronzing paint — specifically, the silver tone found in many radiators today — it would reduce some of the heat transfer. Same goes with “radiator cozies,” knitted covers sometimes placed over the ribs of radiator pipes. They have the added benefit of protecting kids from getting burned, but one reason they became commonplace was as a way to blunt excess heat.
Roughly 80% of residential buildings in NYC are still heated by steam, and surveys with tenants found that 70 % are chronically overheated in winter, according to Demystifying Steam, a 2019 report by the Urban Green Council. The durability of steam “has locked into place technical limitations of a century ago, ” the report noted; their role as disease-fighters forgotten, radiators are now seen as energy-sucking dinosaurs. “Many tenants open windows for relief, even on the coldest days,” the report found, “but steam systems are so unbalanced that other residents in these same buildings don’t receive enough heat.”
Steam’s grip on the city’s building stock has made the challenge of meeting environmental goals much harder, in effect overheating more than merely the buildings in which they operate. According to John Mandyck, CEO of the Urban Green Council, 70% of the climate emissions in New York City are generated by buildings, with the biggest share from the fossil fuels used for heat and hot water in large, multifamily buildings.
Steam might get a bad rap now, but Holohan notes that its inefficiencies can be traced to poor maintenance and long out-of-date building codes. (It’s not supposed to clank either.) “The banging and clanging wasn’t normal,” he says. “Steam heat was fast and silent when it was first installed. When it’s properly tended, it can be an efficient way to heat. Most people just don’t know how to do it right.”
As a Covid-haunted winter looms, residents of steam-heated buildings may get another opportunity to crank their radiators up and put them to their intended use. Holohan says he’s bemused to see his field of expertise reemerge in connection with the current pandemic, as ventilation is being again promoted as a key strategy to cut infection.
“I’ve been talking about this for like 30 years or more,” he says. “And suddenly I’m living it.”