AILSA CHANG, HOST:
And now here is a pandemic story we will start with a showtune.
ARI SHAPIRO, HOST:
Oh, Ailsa, you're speaking my language. In the musical "The Pajama Game," there's a song that uses a metaphor for getting angry. You might say overheated.
(SOUNDBITE OF FILM, "THE PAJAMA GAME")
KENNETH LEROY, CAROL HANEY AND BUZZ MILLER: (As characters, singing) Steam heat - I got steam heat. I got steam heat.
SHAPIRO: All right. If you've ever lived in an older building in the northern U.S., you might have had a steam radiator that was way too hot - like, so hot that you would actually throw your window wide open in the dead of winter. And it might have made a noise like this.
(SOUNDBITE OF RADIATOR CLANGING)
CHANG: Oh, so familiar. As it turns out, radiators that work too well are partly a result of the 1918 flu pandemic. You see; there was once something called the Fresh Air Movement. It called for people to be outside more and for there to be plenty of ventilation indoors.
SHAPIRO: The Fresh Air Movement had some prominent backers, says Dan Holohan. He's author of "The Lost Art Of Steam Heating."
DAN HOLOHAN: Harriet Beecher Stowe teamed up with Lewis Leeds, who was running the Franklin Institute in Philadelphia. And they had this traveling show where they talked about the national poison, which was the vitiated air and closed rooms where there's people breathing. And they're saying that, you know, you've got to have a lot of fresh air.
CHANG: So people took this to heart and opened their windows - not so good during the winter. So heating specialists said to themselves...
HOLOHAN: We need to size the radiators and the boilers to heat the building on the coldest day of the year with the windows open.
SHAPIRO: That might mean the room is too hot at one end and too cold near the window.
HOLOHAN: At that point, they move the radiator from the interior wall to under the window to heat that air as it's coming in.
CHANG: This design philosophy took off after the 1918 flu pandemic and its threat of airborne viruses. So these radiators were designed to heat a room on the coldest day of the year with the window wide open, and then these radiators got even hotter as people switched from coal to other fuels.
SHAPIRO: See; oil and natural gas can be burned in smaller boilers, but often, technicians ignored that.
HOLOHAN: The person doing the replacement, rather than properly size it, is usually going to look at the size that's there and give you the same thing, which is crazy.
CHANG: Suddenly you have a superpowered steam heater, which is one reason they earned a bad reputation, says Dan Holohan. He knows that some city dwellers still open their windows during the winter.
HOLOHAN: I could tell you in Manhattan, by standing across the street and looking at the windows of an apartment building, what kind of heat it has. I could tell that from the outside just by looking at the pattern of open windows.
SHAPIRO: It may seem wasteful today, but steam radiators were a response to a respiratory pandemic just like the one that we are in right now.
(SOUNDBITE OF NELLY SONG, "HOT IN HERRE")
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