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What the 1918 Flu Taught Us About Heating During a Pandemic


In this episode, Dan Holohan shares how the 1918-19 pandemic changed the way we pipe heating systems and the type of windows we use, why radiators are painted silver, and what we can learn from history.


Episode Transcript

In 1989, I was researching steam heating for a book that I would self-publish in 1992. I called it The Lost Art of Steam Heating. To write that book, I had to spend a lot of time in libraries and old-book stores.

I sunk deeply into this story of invention that took place at a time when central heating was brand-new and few people had it in their homes. I learned how heat-loss calculations came to be and all the fits and starts that went into that process. There was so much to consider back then. Insulation was meager and infiltration was rampant. There were so many variables.

As I read those books and technical papers from the days following the Civil War up through the Turn of the 20th Century and beyond, I marveled at how the Dead Men were making this stuff up as they went along. It was a time of great mechanical exploration done in a hurry. And that led to plenty of boiler explosions.

Central heating was a tough sell at first. At one point, they were blowing up a building every 36 hours and much of that had to do with not paying attention to details. But I guess that’s understandable. They were making it all up as they went along.

I read and I read and those long-gone authors would often drop the name of some other long-gone author who had come years before. I’d write down the person’s name and then do my best to find his book. There was no internet at the time. My only tools were card catalogues and those old-book stores. Whenever I was able to make a connection and fill in another piece of the puzzle I was in a state of bliss.

As my reading took me into the 1920s I began to note how the authors wrote about the Fresh Air Movement and how engineers would be wise to size a steam- or hot-water boiler for the coldest day of the year, with the wind blowing . . . and the windows open.

And what the heck was that all about?

This made no sense at all to me at the time, but it did explain why so many boilers and radiators were oversized once you closed those windows. Just look around.

So I dug deeper.

I’ve always been a reader, and that goes for fiction as well as nonfiction. I began to read novels from that time and discovered things I never knew about heating through the authors of those books. Central heating was a marvel at the Turn of the 20th Century and often got described in detail that told me a story. A very human story.

I also read history, and that’s where I learned about The Great Influenza, or what many called the Spanish Flu. This happened during the winter of 1918-19 and it didn’t begin in Spain. We were fighting The Great War, which we now call World War 1. They didn’t call it World War 1 back then because this was supposed to be the war to end all wars.

The Great Influenza began in Camp Funston, Kansas. Two soldiers caught it and it spread quickly throughout the camp. And then those soldiers spread it across the country as they traveled off to the war. And it became a pandemic.

This went on and on because no country wanted to tip their hand to the enemy by letting them know their soldiers were dying of this incredibly contagious disease. They didn’t want to appear weak.

So why Spanish flu? Spain was neutral during The Great War and they were the ones to ring the alarm and urge people to wear masks, and social distance, and lock things down.  But by the time they did, the flu had become a pandemic and went on in two horrible stages to kill at least 50 million people worldwide. 

It was the greatest disaster in human history. But you never learned about it in school, did you? Neither did I. I learned about the Chicago Fire, the Johnstown Flood, the San Francisco Earthquake. But not about the flu. It’s only now that we talk about those dark days as we deal with the ravages of COVID-19.

People were so hurt by The Great Influenza that they didn’t want to talk about it once it was done with us. None of the great novelists of the time wrote about it. People wanted to just move on.

I am the current president of The General Society of Mechanics and Tradesmen of the City of New York, founded in 1785. I spent days combing through our annals, looking for notes about what happened in 1918 and 1919. Not once did they mention it. It was too painful to record. They just sucked it up and moved on. 

And America flung itself into The Roaring 20s, a truly wild time of change. The whole world went a bit crazy, which is easy to understand. 50 million people just died. Everyone lost loved ones. Everyone. Those who survived must have wondered what the heck they were saving it for. So they let it rip. The whole world went roaring nuts for a decade and then it all came crashing down around them with the Great Depression.

But here’s the part that has to do with heating in a pandemic. During that decade of the 1920s, central heating was just starting to take off in a big way, and that’s when the authors of those heating texts began to write about the Fresh Air Movement and the need to keep the windows open.

The Spanish flu was an airborne disease. It was particularly dangerous in closed rooms where people were gathering. Sound familiar? The safest way around this back then was to leave the windows partially open.

Now here’s something I didn’t know, and you may not know it either. The earlier windows were double windows. They kept the heat of a stove inside the building. When steam heat arrived, the double windows gave way to single-pane windows with sashes, specifically because they allowed fresh air to move into the building into the building, and people wanted fresh air. This is why they installed the steam radiators beneath the windows. They warmed the fresh air that flowed in through those leaky sashes. The earlier steam radiators were often on the interior walls and not under the windows because it took less piping to do it that way - on the interior walls. The Spanish flu pandemic changed how we pipe, and the type of windows we used.

When the Great Depression arrived, people closed their windows because they couldn’t afford the coal. That led to overheated rooms, of course. So the National Bureau of Standards did some research and learned that if you paint a radiator with aluminum-bronzing paint, the radiators ability to radiate will drop by 20%. That’s why all those old radiators are silver.

With our current pandemic, the concern is that there’s not enough fresh air moving into our modern buildings. We look toward HEPA filters and other mechanical means to lessen the chance of spreading the virus. But many of our modern, pre-pandemic buildings are focused more on energy efficiency, and not on a big air exchange. They’re tight, and that seemed like a great idea before COVID arrived.

What’s ironic, though, is that our older buildings, those with windows that open and no mechanical ventilating systems, are now outperforming our modern, energy-efficient, hermetically sealed buildings. Everything old is new again.

In New York City, The General Society of Mechanics and Tradesmen of the City of New York’s landmarked building on West 44th Street just got very high performance grades from the City for efficiency. This building went up in 1890 and has the original windows. They are single-pane sash windows and they are leaky. We open them in the summer and the winter. Our steam system is as old as the building and it is fast, quiet, and very efficient because we brought it back to the way it worked on Day One.

I suppose the lesson I’m learning is that when it comes to heating in a pandemic, the old way of doing things is often looking pretty good. And it’s a lot less expensive to install and maintain.

Just some food for thought, and I hope you will think about it. I also hope you’ll share this one with your friends. It’s timely.

And if you haven’t already, please subscribe to this podcast. I have many more Dead Men Tales to share with you.

Thanks for taking the time to listen. It means a lot.

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