Bloomberg: “Your Old Radiator is a Pandemic-Fighting Weapon”

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.

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.

Patrick Sisson

Fascinating piece of history! I would have never guessed that radiators – very common in Romania as well to this day – were invented as a pandemic countermeasure. It makes you wonder which innovations will have a similar impact on society a century from now, while their original purpose is long forgotten.

In the early 20th century, steam heat represented a big step up from coal stoves and fireplaces. Image: New York Public Library Digital Collections

One possible answer is the somewhat counterintuitive finding that cold, dry air facilitates the spread of the coronavirus and of other airborne pathogens. This partially explains why infections have gone up drastically since autumn, because as we start heating the air in our homes, it becomes drier. A similar problem affects air-conditioned indoor spaces. The optimal relative humidity appears to be in the 40 to 60% range. Maybe in a couple of years our heating systems will be designed to take this into consideration, artificially maintaining air moisture in addition to regulating the temperature.

But, as with any technology, steam radiators have their downsides, in this case high energy consumption, which contributes heavily to a city’s emissions and global warming:

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.