A standard CO alarm won’t tell you.
It’s not built to.
It’s carbon monoxide, the silent killer.
Most homes only find out when it’s already serious.
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The furnace has run for hours.
Everyone’s asleep.
A hidden crack leaks CO.
It drifts up the stairs.
Under the kids’ door.
They sleep right through it.
The CO alarm glows green.
It isn’t broken.
It’s doing what it was built to do.
Gas or oil
Gas water
Gas stove
Fireplace or
Attached garage
BackupSo do more than 7 out of 10 US homes.¹
A hairline crack in the heat exchanger.
A bird’s nest in the chimney.
A dryer vent that came loose behind the wall.
The furnace runs.
The house warms up.
Everything seems normal.
Meanwhile, the CO spreads through the whole house.
Up the stairs.
Under the doors.
Into the kids’ rooms.
Every year in the US.²
That’s someone in the ER about every 5 minutes.
And on average, someone dies from it every single day.
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Why they call it “the silent killer”
Gas leak? You smell it right away.
Gas companies add that smell on purpose.
Carbon monoxide gets no warning smell.
Think of your red blood cells as parking spots for oxygen.
You keep breathing normally.
But with every breath, less oxygen reaches your brain and heart.
CO has two speeds.
And slow can turn into fast. A small crack doesn’t stay small.
That’s not us talking. It’s the warning every portable generator sold in the US has to carry.⁶
When you’re asleep, you don’t feel the headache.
You don’t feel dizzy.
You don’t wake up.
The CDC warns: people who are asleep can die from CO poisoning before they ever feel symptoms.²
Something has to warn you.
That’s what a CO alarm is for.
Right?
A CO alarm goes off as soon as there’s CO in the air.
It doesn’t.
Every certified CO alarm in the US follows one rule: UL 2034.⁴
Old or brand new, it decides when your alarm has to go off.
And even above 70, it’s allowed to wait.
It’s built to get a healthy adult out in time.
But not everyone in your home is a healthy adult.
Look around your dinner table:
Kids and seniors are at the highest risk of any age group.²
For them, it gets critical sooner.
The alarm still waits just as long.
Here’s what that wait feels like to a sleeping child:
It feels like being tired.
Like a heavy head.
Like wanting to sleep a little longer.
So they do.
The silent zone
That green light means one thing: it’s plugged in.
It glows the same in clean air
as it does with CO building up all night.
You sleep 8 hours. Your kids sleep 10.
And the monthly test? It checks the beeper. Not whether the sensor still picks up CO.
“We have two kids under 6. The CO alarm outside their room was 11 years old. The sensor had stopped working long ago, but the green light was still on every night.”
Melissa R. · Mom of two
It reassures you. Even when it shouldn’t.
Meet Sentivo Detector™
It turns something you can’t see, smell or feel into a live number on your wall.
★★★★★Already in 2,100+ US families’ homes.
This list works for any device.
Including ours.
Keep your alarm. Add the number.
No beeping at every little spike. Below 50 ppm, Sentivo just shows you the number. From 50 ppm, it warns you.
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Where a standard alarm stays quiet, Sentivo shows the number.
“We had a ‘working’ detector for 6 years. Green light. Beeped when I tested it. First night with Sentivo: 47 PPM in my son’s bedroom. My old detector? Still glowing green. Still silent.”
Bobby M. · Verified buyer47 ppm“Reading 12 PPM in the laundry room three days after installing. The gas dryer vent had come loose behind the wall. No symptoms yet, no beeping alarm, just a number on a screen that told us something was wrong.”
Andrea L. · Madison, WI12 ppm“My $40 alarm upstairs? Quiet as always. The tech found a cracked heat exchanger on our 9-year-old furnace.”
Marcus D. · Des Moines, IA“The live reading is genuinely useful and easier to read than my old alarm. Build quality is okay, not premium. Would buy again.”
Jason B. · Phoenix, AZ100-night money-back guarantee
Free shipping · Not sold on Amazon · Secure checkout · US-based support
Fire safety tip
Fire safety guidelines recommend CO alarms on every level of your home and outside every sleeping area.⁷
Keep them. And put a number next to each one.
Start where your family sleeps: outside the kids’ rooms, outside yours, one near the furnace.
For most homes, that’s 4.
Are your parents over 65?
They’re in the group most at risk from CO.² Cover their home too. That’s what the 8-Pack is for.
Your purchase is protected by our
100-Night “Sleep-Easy” Guarantee
Plug Sentivo in tonight. Live with it for 100 nights. If you’re not sleeping easier, send it back. You get a full refund. We cover return shipping.
More than half of CO deaths from consumer products happen between November and February.³ Order before the heat runs every day.
Is this legit, or just another drop-ship gadget?
Fair question. Don’t just take my word for it: call us at +1 (888) 798-8029 and a real person picks up. And you get 100 nights to try it. Not for you? Send it back for a full refund.
My alarm has never gone off. Do I really need this?
That’s exactly the point. Your alarm doesn’t have to make a sound below 70 ppm, so “never gone off” doesn’t mean “never any CO.” Sentivo shows you the number, so you know instead of guessing.
Won’t a CO number just make me more anxious?
Most of the time, it simply shows 0. That’s the calm part. You only hear from it at 50 ppm or above. Most people tell us they worry less, because they can finally see.
It’s a lot for something I hope I never need.
Totally get it. Think of it like a smoke alarm: you buy it for the one night it matters. Sentivo is built to last 5+ years, and you have 100 nights to decide.
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Your current alarm stays silent until CO hits around 70 PPM, and even then it can still wait before sounding. It only ever says “fine” or “emergency,” nothing in between. Sentivo Detector™ shows the actual number on a display from 0 PPM, so you see a problem building while it’s still just a problem. And unlike a sealed green-light unit, you can always see it’s actually working.
Yes. From 50 PPM it plays a warning tone. From 100 PPM it sounds a loud alarm, even if you’ve muted it. If you’ve turned the screen off for the night, it wakes up automatically on any alarm.
Plug it into any standard wall outlet. You want the display where you’ll actually glance at it. Put one near each sleeping area and one near your main fuel-burning appliance (furnace, water heater or gas stove), plus one per floor. Avoid placing it right next to the stove or in a bathroom. No ladder, no drilling.
Simple rule: one per floor, plus one near every sleeping area and one near your main gas appliance. A typical 2-story home with a basement furnace needs about 4: basement, main floor, and outside the bedrooms. Apartments often do fine with 2.
No. The sensor reads carbon monoxide and gas, not smoke or steam, so searing a steak or a steamy shower won’t set it off. And because you see the actual number rise and fall, you understand what’s happening instead of being startled by a random blare. Just don’t place it right next to the stove or where you use alcohol sprays or strong cleaning products.
This is the whole reason Sentivo Detector™ has a screen. A standard detector’s test button only checks the speaker. Sentivo Detector™ has a built-in self-test, and the live number shows you every day that it’s on and reading the air.
It keeps working. A built-in rechargeable backup battery takes over automatically when the power goes out.
Plug it in tonight and live with it for 100 nights. If you’re not completely happy for any reason, send it back — we refund every cent and cover return shipping. After the trial, every Sentivo Detector™ is covered by a lifetime warranty.
Yes — both. It just plugs into a standard outlet, so there’s no drilling, no hardwiring and no landlord approval needed. It’s also popular for RVs, campers and cabins, where CO from a generator or propane heater is a real risk.
Real humans, usually within the hour during business hours. Pick whatever’s easiest:
Yes — Sentivo Detector™ is simply the new name for the product you knew as Airguard. Same product, same quality, same team behind it. As we grew, other sellers began copying our product and trading on the Airguard name, which created confusion for customers trying to find the real thing. So we’ve brought everything under Sentivo Detector™ — a name that’s fully our own and protects you from imitations. You may still see “Airguard” on some packaging or older materials during the transition; rest assured it’s the exact same product, straight from us.
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★★★★★ 4.8 · 2,127 verified reviews
★★★★★
Bought this after my brother-in-law’s family had a scare. Week 1, Tuesday morning, I see 23 PPM in the basement. My $40 First Alert upstairs? Quiet as always. Cracked heat exchanger on a 9-year-old furnace. Just get the 4-pack. Don’t mess around with this stuff.
★★★★★
My dad is 78 and lives alone in Pittsburgh. Bought him the 2-pack and drove over to plug them in myself. Now when I call him Sundays the first thing I ask is what’s the number say dad and he reads it to me. 0 every time. Silly little ritual but it makes me feel better.
★★★★★
Reading 12 PPM in the laundry room three days after installing. Turned out the gas dryer vent had come loose behind the wall. No symptoms yet, no beeping alarm — just a number on a screen that told us something was wrong. Plumber said another week and we’d have been in the ER. Buy this.
★★★★★
I had three Kidde plug-ins and didn’t know if any of them actually worked. After reading about the 5–7 year sensor life thing I tossed all three and replaced with the 4-pack. Now I can glance at the screen every morning and know it’s working. Worth every penny for the peace of mind.
★★★★★
We have a gas furnace and a baby on the way. My OB literally told us at our last appointment to upgrade our CO detectors. The 4-pack arrived in 2 days and my husband had them all plugged in before dinner. Knowing the number is 0 right outside the nursery lets me sleep.
★★★★★
Had this 2 months. The live PPM readout is genuinely useful and way easier to read than my old Kidde. Only gripe: the alarm is a bit quieter than my old one when you hit test — worth knowing if you have a big house. Build quality is fine, not premium. Would still buy again.
Your alarm will glow green.
Same as every night.
Your home has a CO number right now.
Probably zero.
Is “probably” good enough for your kid?
Keep hoping.
Or put a number on your wall.
100-night money-back guarantee
