My Son Wouldn't Wake Up. Our CO Alarm Was Silent. At 2:14 AM, the Only Thing in the House Making a Sound Was the AirGuard by the Furnace.

Every night this winter, your furnace runs while your kids sleep. A mother on the night hers cracked, why the alarm in her hallway never made a sound, and the one thing a firefighter told her every parent should do tonight.

By David Lawson, Home Safety Editor

As told by Megan Cole, Minnesota · Reader account, names and details changed · 7 min read

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At 2:14 in the morning, the alarm in our hallway was showing a green light. The little screen on the nursery wall said 34. Twenty feet away, my four-year-old was asleep in the room right above the furnace.

I want to tell you exactly how that night went, because the only unusual thing about our house that night was that I happened to be awake.

2:14 AM

The feed

Our daughter Nora was eleven weeks old. If you have had a newborn in January, you know the 2 AM feed: the house dark, the furnace humming, everybody asleep but you.

It was six below outside. The heat had been running more or less nonstop since dinner.

When Nora was born, my mom showed up with a baby-proofing basket. Outlet covers, cabinet locks, corner bumpers, and two small white plug-in monitors with black screens. "For the air," she said. I plugged one in next to the rocking chair because that was where the outlet was. Josh put the other one in the basement next to the furnace, because the card in the box said to put one near anything that burns gas. Then we honestly forgot about them. The one by my chair read 0. Every feed, every night, for eleven weeks.

That night, a little after two, I heard beeping somewhere below me. Faint, through the floor.

Every parent knows the 2 AM chirp of a smoke detector with a dying battery. I rolled my eyes and decided it could wait until morning.

But it wasn't a chirp. It didn't stop. It was a steady, loud beep, coming up through the heat vent.

I looked at the screen next to my chair. It said 31.

I watched it. 32. Then 34.

2:16 AM

What you tell yourself at 2 AM

I woke my husband. Josh looked at the screen, looked at the alarm in the hallway with its green light, and said exactly what I would have said: "It's probably glitching. The real alarm would be going off."

I almost believed him. That is the part that still makes my stomach drop.

"Then go look at the one by the furnace," I said.

He came back up the basement stairs two at a time. The unit next to the furnace was flashing red and beeping, and the number on its screen was over 150. He didn't say anything about glitches after that.

We went straight to Eli. His room sits right over the furnace, with a heat vent under his bed. He was hard to wake. When he finally opened his eyes he said his head hurt, and then he threw up on his blanket.

A four-year-old with a headache and an upset stomach in the middle of flu season. On any other night I would have cleaned him up, given him some water, and put him back to bed.

That night there was a number on the wall.

We wrapped both kids in every blanket we could grab and got them into the car in the driveway. I called 911 with Nora still in my arms.

2:31 AM

What the firefighter's meter said

The engine was there in eleven minutes. The first firefighter in had a meter clipped to his coat. He went through the house room by room while we sat in the car with the heater running, then walked down the driveway and read me the numbers.

Then he asked where our carbon monoxide alarm was. I pointed at the hallway. He went back in, looked at it, and came out shaking his head.

"That alarm is working perfectly. At 27, it isn't allowed to make a sound. And there isn't one in the room where your son sleeps."

I didn't understand what he meant. So he explained it, standing in my driveway in the snow, and I have not looked at that alarm the same way since.

2:45 AM

What the paramedics found

The ambulance crew checked all four of us with a fingertip sensor that reads how much carbon monoxide is bound to your blood. Healthy is under two or three percent.

I read 4. Josh read 6. Nora read 7.

Eli read 11.

They transport anyone over ten. I rode with him, still in the shirt I had been feeding Nora in. On the way, the paramedic told me something I have repeated to every parent I know since: small kids breathe faster than we do and take it in faster, and a sleeping child doesn't feel it as sickness. It feels like being tired. So they stay asleep.

Eli was on oxygen until almost seven. Then he asked for pancakes. I have never cried so hard over pancakes.

The part nobody tells you

Your alarm is allowed to wait. For hours.

Almost every carbon monoxide alarm sold in the United States is built to the same national safety standard. It is the line on the box that makes you feel protected. And it does not say what you would assume it says.

The standard is written to avoid false alarms, so it requires alarms to stay silent at low levels. Below 30 parts per million, an alarm is required not to sound at all, for weeks on end. At 70 ppm, the level where adults start getting headaches, an alarm is permitted to wait anywhere from 60 minutes to 4 hours before making a sound. It only has to react quickly at levels that are already an emergency.

Read that again with our house in mind. Our hallway alarm was sitting at 27, a level it is required to ignore. Eli's room, at 49, didn't have an alarm at all, which the firefighter said is true in most houses he walks into.

Meanwhile the AirGuard by the furnace, sitting at 160, was beeping as loud as it could, and the one next to my chair was showing me 34. Two different ways of saying the same thing: something is wrong, right now.

And on a night like that, the furnace was going to keep cycling until morning.

The next morning

The night after

The next morning an HVAC technician pulled the front panel off our furnace and handed me his flashlight. There was a crack in the heat exchanger, thinner than a fingernail.

"These open up as the metal heats and cools," he said. "Some nights it reads 20. The night it splits, it reads 400. Give it another week of nights like this and you are not talking about a headache."

The firefighter had told me almost the same thing in the driveway, and I am writing it as close to word for word as I can:

"If all you'd had was that hallway alarm, nobody would have known. Not tonight, not tomorrow night. Your boy was sleeping in the worst room in the house, and that number was only going one direction."

Every parent of a newborn prays for the first night the baby sleeps through. I still think about what would have happened if that had been the night. Would a beep two floors down have woken us?

The firefighter didn't think I should count on it. "Put one where every person sleeps," he said. "The number tells you it's building. The beep in the same room is the one that wakes you up."

Before the engine left, the firefighter told me three things I have since repeated to every parent I know:

• The test button tests the horn, not the sensor. Pressing it proves the alarm can make noise. It says nothing about whether the sensor can still detect gas.
• Kids' rooms near the furnace get it first. Rooms over the furnace, over an attached garage, or closest to the supply vents are where carbon monoxide shows up before anywhere else in the house.
• The coldest months are the most dangerous ones. Furnaces run nonstop, windows stay shut, and the whole family sleeps inside a sealed house. That is when his station gets the most calls.

"Keep your alarm," he said. "But what got you out tonight was a beep from the basement and a number on the wall. Put one next to the furnace and one in every room where somebody sleeps."

What's on our walls now

A number next to everyone who sleeps here

We kept the hallway alarm. Every fire department will tell you the same thing: keep a certified alarm on every level. It is built to wake you when levels are already dangerous, and nothing here replaces it.

What we added was what my mom had put in that basket. The monitor on the nursery wall is an AirGuard. Here is what it does, without any of the salesmanship:

• Shows a live carbon monoxide reading from 0 ppm. Not a light. A number, updated continuously, that you read as you walk past.
• Detects natural gas as well. Two sensors in one unit, which matters near a furnace, a water heater, or a gas range.
• Has its own loud alarm at 70 ppm. A red warning light and a beep you can hear through the floor, so it doesn't depend on anyone looking at the screen.
• Shows the temperature too. Handy in a nursery, where you are already watching it.
• Plugs into any standard outlet. No ladder, no wiring, no battery to forget. Setup took me less time than reading this sentence.
• One-touch self-test. Checks the unit is working whenever you want the reassurance.

I ordered a four-pack from my phone in the hospital cafeteria that morning. It took about four minutes. When it arrived, plugging all four in took less time than making coffee: Eli's room, our room, the guest room, and one for my parents' house. The two from my mom stayed where they were, by the rocking chair and by the new furnace.

Now it is part of how we go to bed. Lock the front door, check the baby monitor, glance at the number. It says 0. Every night.

One more thing

Six weeks later, my sister texted me a photo

I want to end with the small version of this story, because the small version is the one that will actually happen to you.

After that night I sent one to my sister in Wisconsin. Six weeks later, at 6:50 on a Sunday morning, she texted me a photo of the screen. It said 9.

Not 34. Nine. A standard wall alarm will never react to 9, and a year earlier, neither would I.

The vent pipe on her water heater had come loose behind the tank. A plumber had it fixed by lunch.

That is the whole point. Not the night with the ambulance. The quiet Sunday morning where a number says something is slightly off, and you fix it before it is anything at all.

I have bought six more since. One for every baby shower I have been to this year. It goes in the basket, between the outlet covers and the corner bumpers, with a note: For the air.

Tonight

Tonight, your furnace is going to turn on

Sometime after you fall asleep tonight, your furnace will kick on. Then again around one. Then three. Then five.

Every one of those times, the alarm in your hallway will show the same green light, whether the air in your kids' rooms is clean or not.

You don't have to tear anything off your wall. You don't need an electrician, a ladder, or a free weekend.

You need a number next to the people you love. It plugs in. It takes about thirty seconds.

Below 70, it shows you the number. At 70, it sounds its own alarm, so it doesn't depend on someone being awake to read it.

A light tells you nothing until it's almost too late. A number tells you what's happening now, and a beep makes sure you hear it. For us, that was the difference between a scary night and the worst one of our lives.

See what a standard alarm can't show you.

AirGuard plugs in and shows live carbon monoxide and gas readings from 0 ppm. Set up in under a minute. Available in multi-packs for every level of your home.

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