In the 2015 horror film The Blackcoat’s Daughter, there’s a midnight scene where a teenager named Kat slips out of her room and into her boarding school’s dorm basement. An older girl named Rose, apparently the only other student left at the school over winter break, grows curious and follows. Old pipes creak and whine as Kat’s indecipherable voice floats on the air, her murmurs part of a one-sided conversation only she is privy to. As Rose creeps toward the boiler room, a dull, rhythmic boom grows louder. She peeks through a window in the door to see Kat violently, repeatedly prostrating herself in front of the enormous glowing boiler. 

Part of the horror of this scene comes from a shared, familiar unease: we’ve all had the experience of not knowing what sounds our home is making or why. In this way, my cat Poe is also like a possessed Catholic schoolgirl. Sometimes, he looks like he’s worshipping the miracle of home heating systems, but clearly he’s actually communing with the devil. His conduit isn’t a boiler but rather our apartment radiators, and specifically the one in our bedroom—and only when the radiator is as cold and silent as a headstone. Roll over at 3 AM and crack your eyes open, and there he is, an inky, furry little goblin sitting upright and motionless in front of the flaking radiator. Worshipping, communing, listening. When we call his name, not even his ears twitch.

I’m new to radiators. The furnace in the bungalow I grew up in made its own sounds—and shot out dry dust—when it turned on. But radiators, man. As disturbing as it is when my cat fixates on their silence, it’s taken me a long time not to be equally concerned by their noise. They look like xylophones but sound like teapots, hissing and whistling. Other days, they make a clanking and then a terrible metallic grinding that reminds me of another movie scene—when the iceberg rips raw the starboard hull of the Titanic. Occasionally, if the rest of the room is quiet, I can hear water trickling inside the radiator’s coils, like a barely-on bathtub faucet.

The hissing and trickling I kind of like. And because I grew up with five siblings, clanging and banging are noises I’ve long been conditioned to ignore. But the whistling? The whistling really freaks me out. What does it mean? What is my radiator trying to tell me? Is it about to blow up? Am I going to die?

“No,” says José Campuzano, owner of JC Radiators in Humboldt Park. His voice over the phone is gravelly and low, and he’s patient with my questions and economical with his words. For the past ten years, his job has been bringing old radiators back to life. 

José grew up with radiators. In a warehouse in the city, he stores a thousand radiators he’s collected over the years as part of his work. He just finished installing 24 radiators throughout his own home, cutting his heating bill to about a quarter of what it was when he used forced air.

“I think a lot of the newbodies, I don’t know how you wanna call them—millennials—they just don’t know radiators,” José says. Guilty as charged. “They see them as an antique, or a dying type of heat. But they’re here for a reason. Forced air is an inferior way of heating property. Radiators should not be removed,” he finishes, his growl dropping to a whisper. In the past few seconds, José has spoken more words than he did in the past 15 minutes. I’m interested. 

“What do their sounds mean?” I ask. “Is it a language you understand?”

“Yes,” he says. It turns out the whistling I hear is not a threat. Hissing or whistling is just a sign that the radiator is working properly as it releases air. Banging and hammering, however, are something else.

Steam radiators, the kind we’re talking about, are especially common in old Chicago apartments and homes. They’re powered by water heated in a boiler, which is usually located in the basement (so as to be closer to the devil). The resulting steam travels through a pipe to the radiator, which radiates out the heat; as the steam cools, it condenses back into water and returns to the boiler. 

If a radiator is making lots of banging or hammering noises, it’s a sign that either it or the pipes connected to it are pitched incorrectly. As a building settles, pipes can shift so that they’re tilted or angled in the wrong direction, making it harder for the condensing water to get where it needs to go. “You don’t want to hear any of the banging or the hammering,” José tells me. 

Water trapped in the radiator or pipes can cause a leak, or worse. Steam forcing its way through water—one of the main causes of those undesirable sounds—puts stress on the metal, because water doesn’t compress like steam. Pooled water can also weaken metal by causing corrosion.

“Cast iron shatters like glass,” José helpfully explains. Imagining this, I let out an involuntary “Oh God.” José gives out a dry chuckle. “Yeah, it’s really soft and brittle, but it’s heavy as heck.”

“I should call my landlord,” I say out loud, thinking about the banging and clanking I hear from the radiator in our apartment stairwell. “No,” José corrects me. “Call JC Radiators.”

A few days later, I do. “José,” I say, “one more thing.”

“Sure,” he says.

“Why does my cat sit and listen to the radiator even when it’s cold and quiet?” I think but don’t ask, Is he possessed?

I can hear the shrug in José’s voice. “They hear better than we do.” So even before the radiator starts up, he hears water in the pipes in the walls, or deep down within the boiler? “Yup,” he confirms, then pauses. “Make sure you add my name to that.”

The Sound Issue