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Best CO2 monitor UK

Updated: 20 October 2026

You want a best CO2 monitor UK shortlist that survives the star line and the sales rank, not a crown for whichever listing shouts loudest. On 19 October 2026 the three amazon.co.uk listings in our [CO2 detector](/hub/fire-protection/co2-detector) comparison pointed three different ways: Bekasa at about £16.99 was 3.1 from 199 reviews and ranked 3 in CO2 Detectors, GoHelmate at about £69.99 was 5.0 from one review, and BREATHE at about £99.99 was 4.0 from 457 reviews with NDIR named in the bullets. Products Compared did not test them with gas. The criterion is a named NDIR sensor plus a review count large enough to show the faults. A qualifying purchase can earn a commission at no extra cost to you.

You want a best CO2 monitor UK shortlist that survives the star line and the sales rank, not a crown for whichever listing shouts loudest.

Our top picks

GoHelmate GoHelmate MT29 15-in-1

Best overall

GoHelmate GoHelmate MT29 15-in-1
3.3/10about £69.99
View offer
BREATHE BREATHE Airmonitor Plus Gen 2

Rank 2

BREATHE BREATHE Airmonitor Plus Gen 2
6.8/10about £99.99
View offer
Bekasa Bekasa 5-in-1 carbon dioxide detector

Alternative

Bekasa Bekasa 5-in-1 carbon dioxide detector
3.1/10about £16.99
View offer
On this page
  1. 1.What best means on this page
  2. 2.BREATHE Airmonitor Plus Gen 2
  3. 3.GoHelmate MT29
  4. 4.Bekasa 5-in-1
  5. 5.A conditional recommendation

What best means on this page

Best, here, means the listing a careful buyer can defend: carbon dioxide rather than carbon monoxide, NDIR named on the page, and enough amazon.co.uk reviews to see what breaks. It does not mean the highest star rating. GoHelmate's 5.0 is one review, and that review does not compare a ppm figure with a window open and a window shut. The Health and Safety Executive names non-dispersive infrared monitors as the portable type for workplace ventilation checks. The checks behind that order are on the CO2 monitor buying guide.

BREATHE Airmonitor Plus Gen 2

The BREATHE Airmonitor Plus Gen 2, model BTL40001, is the top pick if you want a listing that names NDIR and has a large review count. At about £99.99 it lists NDIR CO2 plus PM1, PM2.5, PM10, TVOC and formaldehyde, with USB-C for continuous use. The same listing's technical details say sensor type TVOC. That line does not erase the NDIR claim, and the NDIR claim does not erase the TVOC line. Of the first 50 written reviews in the saved listing, only three are marked United Kingdom. Those three mention Wi-Fi disconnects, a CO2 channel that failed after about 10 days, and poor battery life. Placement, once you own it, is on the how to use a CO2 monitor page.
GoHelmate GoHelmate MT29 15-in-1

Testsieger

GoHelmate GoHelmate MT29 15-in-1
3.3/10about £69.99
View offer

GoHelmate MT29

The GoHelmate MT29, at about £69.99, is a 15-in-1 with a colour screen, an audible alarm, and a list that includes CO2, particles, VOCs, humidity, temperature and air pressure. The listing says the device needs an internet connection and that data is stored in the cloud. NDIR is not stated. Battery life is not stated. It carries the best-value mark on the main comparison only because the BREATHE listing already holds the top pick, and the value block sits just above the about £16.99 electrochemical listing. One 5.0 review cannot carry a top pick. Choose the MT29 only if you want a mid-price multi-reading screen and you accept an unstated sensor and a single review.

Bekasa 5-in-1

The Bekasa 5-in-1, model Culp-DS-ZXD0246-B, at about £16.99, states an electrochemical sensor and says calibration is not required. The alarm is visual. There is no app. It is 3.1 from 199 reviews, and the sales rank does not improve it. Of 20 UK reviews in the saved listing, the repeated complaints are inaccurate or stuck CO2 readings, numbers that stay high outdoors, and charging that fails unless the unit stays on USB power. HSE does not recommend an electrochemical cell for this job. Rank 3 in the category is how many people bought it, not how it performed in fresh air.

A conditional recommendation

Buy the BREATHE Airmonitor Plus if you want the only listing in this set that names NDIR carbon dioxide and has hundreds of reviews, and if you can live with USB-C power, a sensor field that also says TVOC, and UK complaints about battery, Wi-Fi and a failed CO2 channel. Do not buy GoHelmate because the star is 5.0. Do not buy Bekasa because it is cheap or because it ranks in CO2 Detectors. None of the three replaces a carbon monoxide alarm where fuel is burned.

Common questions

Is £99.99 enough, or do I need the Aranet4?
About £99.99 is enough to buy the named-NDIR listing inside this comparison, with the faults above. The Aranet4 Home was about £176 to £189 on amazon.co.uk the same day, with NDIR named and 4.6 from 1,824 ratings, and it was not scored here. Move up only if you want that larger public record. We did not verify either meter with calibration gas.
Does best mean we tested them with gas?
No. Products Compared compared amazon.co.uk listings, review counts and public UK guidance. There is no lab score. Top pick on the main page means the highest score on that method, which rewards a named NDIR claim and a large review file, then deducts for the documented complaints.
What if I only need a bedroom trend, not particles and formaldehyde?
You still want the CO2 channel to be NDIR, or at least named as such. Extra particle and formaldehyde lines are optional. BREATHE includes them, which is more meter than a bedroom needs, and the night-time pattern in non-UK reviews is the part that matches a shut window. You do not need the GoHelmate's 15-in-1 list to watch one room, and you should not accept Bekasa's electrochemical claim just because the feature list is shorter.
Can I use the winner as my carbon monoxide alarm?
No. The BREATHE listing is a carbon dioxide and air-quality meter. It is not described as a BS EN 50291 carbon monoxide alarm. A boiler, gas fire, wood stove or other fuel-burning appliance still needs its own CO alarm. If you suspect carbon monoxide, leave the space. Do not wait on this screen.
Who should not buy the £16.99 unit?
Anyone who will treat the number as a ventilation decision. The Bekasa listing states an electrochemical sensor, HSE prefers NDIR for this check, and UK reviews report readings that stick, disagree or stay high outdoors. A campervan user who only wants a screen on mains power is the narrow exception already in those reviews, and even then the CO2 channel is disputed.

Related pages

CO2 detector vs carbon monoxide alarm

CO2 detector

CO2 monitor buying guide: NDIR before the star line

Classroom CO2 monitor: the 800 ppm and 1500 ppm bands

How to use a CO2 monitor at head height, then wait

Sources

Public UK sources and amazon.co.uk listings from the research digest, checked on 19 October 2026.

  1. HSE: Using CO2 monitors (retrieved 19 October 2026)
  2. HSE: Carbon dioxide health hazards (retrieved 19 October 2026)
  3. HSE: EH40/2005 workplace exposure limits (retrieved 19 October 2026)
  4. GOV.UK: Ventilation and air quality in education and childcare settings (retrieved 19 October 2026)
  5. Department for Education: CO2 how-to guide (2023) (retrieved 19 October 2026)
  6. Building Bulletin 101: ventilation, thermal comfort and indoor air quality in schools (retrieved 19 October 2026)
  7. Shared Health Foundation: How to use a CO2 monitor (retrieved 19 October 2026)
  8. amazon.co.uk: BREATHE Airmonitor Plus Gen 2 listing (retrieved 19 October 2026)