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MildWell

Halevon Real-Time CO Detector showing live PPM reading

★★★★★ 4.8 / 5 (6,300+ Reviews)

Stop Guessing What's In Your Air — See The Actual Number

A plug-in carbon monoxide detector with a real-time digital display, so you can see the exact CO level in any room of your home instead of waiting for a single beep that may come too late.

✓ Shows the live CO level in PPM on a bright digital display, updated continuously
✓ Electrochemical CO sensor designed to register low-level readings, not only high spikes
✓ Loud 85dB audible alarm plus a clear visual warning if CO climbs to an elevated level
✓ Plugs into any standard outlet — no tools, no wiring, no installation

Choose Your Coverage — Buy More, Save More

1 Detector

Cover One Room — your highest-risk area

$119.99 $79.99

Save $40

2 Detectors

For apartments & single-level homes

$239.99 $119.99

Save $120 · $59.99 each

"I Plugged It In And Finally Saw A Number Instead Of Wondering"

I'd been worried about our old gas stove for a while but had no way to know what was actually in the air. The night I plugged Halevon in, the display showed a low reading in most rooms but ticked higher near the kitchen. I had an HVAC tech come out, he found a venting issue, and now I can glance at the screen and see it's clear. It's the peace of mind I was missing.

— Jennifer M., Austin TX

✔ Verified Buyer

1 PPM

Reads CO From As Low As 1 PPM

365

Day Money-Back Guarantee

30s

From Outlet To First Reading

A Single Beep Isn't The Same As Actually Knowing.

Most carbon monoxide detectors only do one thing: stay silent until CO climbs high enough to trip a single alarm — and then beep. They never tell you whether the air you're breathing right now is at 0, 8, or 25 PPM. Lower-level CO can come and go for weeks from a faulty gas stove, a cracked water-heater vent, or an aging furnace, and a basic alarm gives you no way to see it. On top of that, standard detectors quietly reach the end of their service life and most families never realize the unit on the wall has stopped protecting them. Halevon takes a different approach: a bright digital display shows you the live CO reading in that room, updated continuously, so you're looking at a number instead of waiting on a beep.

Here's Exactly What You Get

A real-time digital readout, an electrochemical CO sensor, and a loud audible-plus-visual alarm — in a unit that simply plugs into the wall.

A Live PPM Reading

See The Real Number, Updated Continuously

Halevon shows the current carbon monoxide level in that part of your home on a bright digital display — readable day or night. Instead of guessing what's in your air, you simply look at the number. If it's low, you have measured confirmation; if it's higher than expected, you know to take action.

Electrochemical Sensor

Built To Register Low-Level CO, Not Only High Spikes

Many basic detectors are built to alarm only once CO reaches a high threshold. Halevon uses an electrochemical carbon monoxide sensor designed to register CO from as low as 1 PPM and show it on the display — so a slow, low-level source has somewhere to show up instead of going unseen.

Halevon continuous CO and gas detection features

Loud 85dB Alarm

Audible And Visual Alert When It Matters

If carbon monoxide reaches an elevated level, Halevon sounds a loud 85dB alarm and shows a clear visual warning you can see across the room, so the whole household is alerted quickly. The display keeps showing the live reading the entire time, so you can see exactly what's happening.

Clear, Simple Controls

Easy To Read And Easy To Use

A clear OLED display with adjustable brightness, a night-safe glow, and simple one-button controls for self-test, temperature units and mute. No app required, no complicated setup — just plug it in and read the screen.

Why Families Put Halevon On The Wall

📟

See The Real Number

A live digital PPM display shows the actual carbon monoxide level in the room — not just a single beep when it's already high.

🔌

Plug-In Simple

Goes into any standard outlet in under a minute. No wiring, no tools, no installation — just power and read.

🏠

Cover Every Source

Place one near each gas appliance and in bedrooms, removing the blind spots a single detector leaves behind.

🛡️

Risk-Free To Try

Backed by a full 365-day money-back guarantee, so you can put it on the wall and see for yourself with nothing to lose.

Halevon vs. Standard Beep-Only Detectors

A basic alarm waits in silence until CO is already high. Halevon shows you the number the whole way there.

Feature	Standard Beep-Only CO Detectors	Halevon
Shows the real-time CO level on a display	✕ Indicator light only	✓ Live PPM display
Registers low-level CO, not only high spikes	✕ Stays silent	✓ From 1 PPM
Electrochemical carbon monoxide sensor	✕ Often basic sensors	✓ Yes
Plugs into any outlet — no wiring needed	✕ Hardwired or mounted	✓ Plug-in
Backed by a 365-day money-back guarantee	✕ Varies	✓ 365 days

Every Gas Appliance Is A Potential Source. Cover Them All.

Carbon monoxide doesn't build evenly — it concentrates near the source and settles where your family spends the most time. To really know what's in your air, it helps to cover each source.

Kitchen

Near Your Gas Stove

A gas stove is one of the most common sources of low-level CO in the home. Placing a detector nearby lets you see the reading every time you cook, just a few feet from where your family eats.

Utility Area

Near Your Water Heater Or Furnace

Water heaters and furnaces run quietly all day. A hairline crack or a partially blocked vent can release CO with no visible sign — this is where families often find the highest readings.

Bedrooms

Where You And Your Kids Sleep

You spend 7–8 hours a night in your bedrooms. If CO is building anywhere in the home, this is where the longest exposure happens — and where a clear reading matters most.

Trusted by HVAC technicians and firefighters

The People Who See It Up Close

Trusted By HVAC Technicians & First Responders

HVAC technicians, firefighters and other professionals see what carbon monoxide can do to families — and they value a detector that shows the actual number, not just a single beep once levels are already high.

Halevon is built around that same idea: a clear real-time reading, an electrochemical sensor that registers low-level CO, and a loud alarm if levels climb. It plugs into any outlet, so it's easy to put one wherever a gas appliance lives.

Three Steps To Knowing What's In Your Air

Plug It In

Plug Halevon into any standard wall outlet — no tools, no wiring, no electrician. It begins monitoring the moment it has power.

Read The Number

Look at the digital display to see the real-time carbon monoxide level in that part of your home, updated continuously and readable day or night.

Act On What You See

If a reading is higher than expected, ventilate the area and contact a licensed HVAC technician to inspect your gas appliances. If it stays low, you have measured confirmation your air is clear.

Crystal-Clear Display

A Display Built To Be Read At A Glance

Many basic detectors hide everything behind a tiny indicator light. Halevon's bright OLED display shows the live CO level clearly, with adjustable brightness and a night-safe glow so you can read it across the room, day or night.

Halevon clear display compared to basic detectors

Know What Your Family Is Breathing — Starting Tonight

Plug Halevon in and look at the number. Every day you wait is another day of guessing, when you could simply see the reading on a screen.

Why we built it

We Wanted A Detector That Showed The Number, Not Just A Beep

We started MildWell because a basic alarm on the ceiling never sat right with us. It tells you nothing on a normal day — no reading, no reassurance, no way to tell whether a quiet gas-appliance fault has been leaking low-level CO for weeks. We wanted a detector our own families could glance at and simply see the number. So Halevon shows the live carbon monoxide level on a clear display, plugs into any outlet, and still sounds a loud alarm if levels climb. No drama, no overblown claims — just the actual reading, backed long enough for you to trust it yourself.

— The MildWell Team

Thousands Of Families Finally Know What They're Breathing

4.8

★★★★★

Based on 6,300+ reviews

55,733

4441

395

219

112

96% would recommend this product

Sarah T.

✔ Verified Buyer

★★★★★

Finally a real reading, not a guess

I love that I can actually see the level instead of waiting for a beep. Most rooms read clean, but I saw a higher number near the water heater and had it checked out. So glad I could see it instead of wondering.

2 weeks ago

Mark D.

✔ Verified Buyer

★★★★★

The display sold me

Our old detector was just a beeper that never went off. This one shows the live number in every room I put it in. Plugged it in, had a reading in seconds, no tools needed. Bought a few more for the bedrooms.

3 weeks ago

Linda K.

✔ Verified Buyer

★★★★★

Peace of mind for an older home

We have a gas stove and an aging furnace, so I wanted something I could actually read. The screen is bright and easy to see at night. It's reassuring to glance over and see a low number.

1 month ago

James H.

✔ Verified Buyer

★★★★★

Bought a set for my parents

My parents are in their 70s with an older furnace and I wanted them protected. Setup was as simple as plugging it in. Now they can see the number themselves and I feel a lot better. Worth it for the whole family.

1 month ago

365DAY GUARANTEE

The 365-Day See-It-For-Yourself Guarantee

Plug Halevon in and watch the number for a full year. If it isn't giving you the clarity and peace of mind you expected, contact us within 365 days for a full refund. We want you protected, not stuck with something that doesn't earn its place on your wall.

Questions From Homeowners

How is this different from a normal CO detector? +

A standard detector stays silent until carbon monoxide climbs high enough to trip a single alarm, then beeps. Halevon adds a real-time digital display that shows the current CO level in the room continuously, so you can see low-level readings a beep-only detector would never reveal. It still sounds a loud alarm if levels become dangerous.

How do I install it? +

There's no installation — you simply plug Halevon into any standard wall outlet. No tools, no wiring, no electrician. It begins monitoring the moment it has power, and the display updates in real time.

How many detectors do I need? +

Carbon monoxide concentrates near its source, so we recommend one near each major gas appliance — your stove, water heater and furnace — plus the bedrooms where your family sleeps. Most homes use several units to cover every potential source, which is why we offer multi-packs with a lower cost per detector.

Will cooking on a gas stove set it off? +

You may see the live display tick up slightly while you cook, which is the device doing its job and showing the real CO level at that moment. The alarm is designed to sound only when CO reaches an elevated level, not during normal cooking. If you regularly see high readings, ventilate and have your appliance inspected.

What should I do if it reads high? +

If you see an elevated reading or the alarm sounds, move to fresh air, ventilate the area, and contact a licensed HVAC technician to inspect your gas appliances for the source. If anyone has symptoms of CO exposure such as headache, dizziness or nausea, leave the home and call emergency services. Halevon helps you see and be alerted to CO; a qualified professional diagnoses and repairs the source.

What is your return policy? +

Every order is backed by a 365-day, 100% money-back guarantee. Plug Halevon in, watch your air, and if you're not satisfied for any reason within 365 days, contact us for a full refund.

Halevon Real-Time CO Detector · 3 Detectors ~~$359.99~~ $159.99

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Stop Guessing What's In Your Air — See The Actual Number

"I Plugged It In And Finally Saw A Number Instead Of Wondering"

A Single Beep Isn't The Same As Actually Knowing.

Here's Exactly What You Get

See The Real Number, Updated Continuously