Had a basic CO detector for years and never really trusted it. Switched to this one after a friend recommended it. The live PPM display is a game changer — I can actually see the number every morning. Installed in 10 seconds. Worth it.
Protect Your Family Against the Silent Killer
Forbes
VOGUE
Women's Health
WHAT MOST PEOPLE NEVER TELL YOU
Most CO alarms stay quiet until the danger has already started.
Carbon monoxide can affect your body before many standard alarms sound. Seeing CO levels in real time gives you an earlier warning, so you can act before the situation becomes more serious.
30 PPM
Early symptoms may begin
50 PPM
Exposure becomes more concerning
70 PPM
Many standard alarms respond around this level
Don’t Become the Next Headline.
Carbon monoxide is one of the leading causes of accidental poisoning deaths in the UK.
Every year, dozens of families across the UK lose a loved one to carbon monoxide poisoning — often while they’re asleep.
The danger is invisible. Carbon monoxide is odourless, colourless, and tasteless. It can come from boilers, water heaters, fireplaces, gas cookers, and portable generators.
An ageing detector or one that reacts too late may leave your family unprotected when every second matters.
Early detection can save lives.
The detector that shows you what others hide.
Plug it in, see live CO levels in real time, and know your home is safe — before a standard alarm even reacts.
See CO from 0 PPM — not just a green light
Watch carbon monoxide levels rise in real time instead of waiting for a delayed alarm to beep.
Plug in and protect your home in 30 seconds
No tools. No wiring. No electrician. Just plug it into any standard outlet.
No false alarms while cooking
Detects carbon monoxide and gas — not smoke, steam, or everyday cooking fumes
4 sensors. One smarter detector.
Monitors carbon monoxide, gas, temperature, and humidity in one compact device.
90-day risk-free trial
Try it at home for 90 days. If it’s not right for you, return it for a full refund.
Developed with Firefighters. Built to Protect Families.
Hilair was developed with firefighters who have seen firsthand how carbon monoxide tragedies happen—and how every second matters.
Every feature is designed to help you detect danger earlier and protect your family sooner.
- Professional-Grade Electrochemical Sensor — accurate carbon monoxide detection you can rely on.
- Real-Time PPM Display — see CO levels rise second by second instead of relying on a simple green light.
- 4-in-1 Protection — monitors carbon monoxide, gas, temperature, and humidity in one compact device.
Hilair isn’t just another detector. It’s built to help you spot danger sooner and act before it becomes an emergency.
Like having a firefighter watching your air quality 24/7.
4.7/5 on 479 reviews
Loved by hundreds of families
We cook with gas and I always worried about it. This thing sits right by the kitchen and gives me a real number instead of just beeping when it's already bad. Temperature and humidity are a bonus I didn't expect to use but now check every day.
Plugged it in, showed 0 PPM, all good. The screen is clear and readable from across the room. My only minor gripe is the alarm beep could be louder for a larger home — but for an apartment or small house, perfect. Arrived in 4 days.
Three weeks after plugging this in, I noticed the reading jump to 18 PPM one evening. Turned out the furnace wasn't venting properly. Called a technician the next day. No alarm had gone off yet — just the number on the screen tipped me off. Glad I had it.
Build quality is decent, not premium, but the screen is genuinely good — bright and easy to read. Setup is instant. Came well packaged and arrived within 5 days. Would buy again for another room.
Just bought my first home with a gas furnace. This was one of the first things I ordered. The display is always on and I glance at it every morning — it reads 0 and I go about my day. That's exactly what I wanted.
Most CO detectors just sit there and you never know if they work. This one shows you a live reading 24/7. When I saw it hit 9 PPM during a cold snap, I checked the furnace filter. Turned out it was completely clogged. Might have saved us a real problem.
Renting an older apartment with gas heat. Bought this myself after reading about CO risks. Reads 0 every day, which is reassuring. The screen is bright enough to see from the hallway.
Free shpping
3–7 Day Delivery
Lifetime Warranty
Free replacement if your detector ever fails.
90-Day Trial
Try it risk-free with easy returns.
Secure Checkout
SSL-encrypted payments for every order.
Frequently asked questions
Everything you need to know before you order.
What does this detector measure?
It monitors carbon monoxide (CO) concentration from 0 to 999 PPM, along with temperature (14°F to 122°F) and humidity (0–95% RH) — all from one compact plug-in device.
How do I install it?
No wiring required. Simply plug it into any standard wall outlet. The US plug version is compatible with North American outlets and is ready to use immediately.
At what level does the alarm trigger?
The alarm activates by default at 51 PPM of CO. Four alarm levels with both visual indicators and an audible alert keep you informed as CO readings rise.
What does the screen display?
The 2-inch IPS screen (320×240) continuously shows CO levels, temperature, and humidity. You can adjust brightness, rotate the display, and switch between °F and °C using the built-in buttons.
Which plug version should I choose?
For the US market, select the US Plug version. Make sure to choose the correct plug type for your outlet when ordering.
Does this detector replace professional safety systems?
No. It is designed to monitor and alert, but does not replace proper installation, maintenance, or advice from a qualified safety professional.