See the number. Not just a light.
- See the level any time – 0 to 999 ppm on screen
- Plug in and go – any UK socket, no app or Wi-Fi
- 85 dB alert – and colour-coded levels if CO rises
- Temperature and humidity – on the same screen
- Free tracked UK delivery
- 30-day returns
- Lifetime warranty: 10 years from delivery Details
Plug-in Carbon Monoxide Monitor with Display · Model S02-CO
A light says it's on. A number says more.
HALDEN shows the carbon monoxide level in the room as a number, so you can check it whenever you like, not just when something sounds. It works alongside the alarm you already have.
Plug in. Look. Listen.
Plug in
Use a standard UK wall socket and switch it on. If the socket is upside down, hold the bell button to flip the display.
See the level
The CO reading in ppm, plus temperature and humidity, any time you walk past.
Hear the alert
If CO rises, the screen changes colour and an 85 dB alert sounds. Short press the top button once a month to test it.
What the colours mean.
Green: 0–50 ppm
Normal. The green light pulses gently and there's no sound.
Yellow: 51–100 ppm
A yellow warning shows on screen, the orange light pulses and the alert sounds.
Orange: 101–150 ppm
An orange warning shows on screen, the orange light flashes and the alert sounds.
Red: over 150 ppm
A red warning shows on screen and the red light flashes. The alert can't be silenced and the screen stays on.
HALDEN vs a typical alarm.
"Typical alarm" means a CO alarm without a screen. Features vary by model.
Rooms with a fuel-burning appliance.
Many homes need two to four. Keep it away from direct heat, windows and draughts.
The details.
| Detects | Carbon monoxide; also shows temperature and humidity |
| CO range | 0–999 ppm (±10%) |
| Sound alert from | 51 ppm (default) |
| Alert volume | 85 dB |
| Display | 2.0-inch colour IPS, 320 × 240 |
| Power | 100–240 V AC, 50/60 Hz, with a detachable plug head |
| Back-up battery | None. It needs mains power. |
| Temperature | −10 to 50 °C (±1.5 °C), °C or °F |
| Humidity | 0–95% RH (±5%) |
| Screen brightness | 100%, 50% or off |
| Screen flip | 180° |
| Sensor type | [To confirm with manufacturer] |
| Operating temperature | −10 to 50 °C |
| Casing | Flame-retardant ABS |
| Size | 105 × 55 × 52 mm, including plug |
| Weight | [To confirm] |
| Sensor life | [To confirm with manufacturer] |
| In the box | Monitor, plug head, user manual |
| Certification | CE marked |
| Warranty | Lifetime: 10 years from delivery |
One for every room with a boiler, fire or cooker.
Questions.
How many do I need?
One in each room with a fuel-burning appliance, such as a boiler, gas fire, cooker or wood burner. Many homes need two to four.
Isn't a wall socket too low? Doesn't carbon monoxide rise?
Carbon monoxide weighs almost the same as air, so it doesn't collect at the ceiling. It mixes through the room as it spreads. Warm fumes from an appliance can drift upwards first, so for the earliest reading, plug HALDEN in 1 to 3 metres from the appliance and use a higher socket where you can, such as one above a kitchen worktop. In bedrooms, a socket near the bed puts it close to where you breathe while you sleep. Keep any ceiling CO alarm you already have: HALDEN works alongside it.
How do I set it up?
Plug it into a standard UK wall socket and switch it on. If the socket is mounted upside down, hold the bell button to flip the display so it reads the right way up. Then short press the top button to run a self-test.
Do I need an app or Wi-Fi?
No. It works on its own as soon as it's plugged in.
How do I test it?
Short press the top button once a month. The monitor should sound and the light should flash.
Can I turn the screen off at night?
Yes. The brightness button cycles between 100%, 50% and off. At the red level the screen and alert stay on.
Does it work in a power cut?
No. It has no back-up battery, so it needs mains power.
What does the warranty cover?
Every HALDEN monitor has a lifetime warranty covering its working life of 10 years from delivery. If it develops a fault from normal use, send us a short video or photo and we'll replace it free of charge.
Can I return it if I change my mind?
Yes. Tell us within 30 days of delivery and send it back for a full refund. See our returns information for details.
What should I do if it sounds?
Follow the steps in the user manual that came with your monitor.
Still have a question? Contact us.
Delivery, returns and warranty.
Delivery
Free tracked delivery to anywhere in the UK, with no minimum spend.
Returns
Changed your mind? Tell us within 30 days of delivery and return it for a full refund.
Lifetime warranty
Covered for its working life of 10 years. If it develops a fault, we'll replace it free of charge. Your legal rights aren't affected.
Know what's happening at home.
From £29.50 each in an 8-pack. Free tracked UK delivery and 30-day returns.
Choose your pack