Best air quality monitors UK (2026) — compared & price-tracked
An indoor air quality monitor tells you what is in the air of one room — usually carbon dioxide, particulates or airborne chemicals — so you can decide whether to open a window, run the extractor fan or look harder at a damp corner. What none of the monitors on this page does is replace a carbon monoxide alarm certified to EN 50291, and most of them give no warning of carbon monoxide at all. The useful question is not which unit carries the most sensors, but which readings you would actually act on: CO2 for ventilation, PM2.5 for cooking and wood smoke, radon if you live in an affected area. Prices below are tracked against UK retailers and checked against each manufacturer's own documentation.
By Tom Calder · Updated 18 July 2026 · 6 products, price-tracked
Before you buy
Start with the reading you would actually act on, because "air quality monitor" covers devices that measure entirely different things. Carbon dioxide (CO2) is a proxy for ventilation — it climbs when people are breathing in a room that is not getting fresh air, and falls when you open a window. Particulate matter (PM2.5) covers the fine particles thrown out by cooking, wood burners, candles and nearby traffic. VOCs are airborne chemicals from cleaning products, paint and new furnishings, and most consumer devices report them as a rough trend rather than a precise figure. Radon is a naturally occurring radioactive gas that matters in specific parts of the UK. Almost nothing at consumer prices covers all four well, so pick the one or two readings that would genuinely change what you do, and buy the device that measures those properly.
The most consequential confusion in this category is CO2 versus CO. Carbon dioxide is what you breathe out, and it is what a ventilation monitor tracks. Carbon monoxide is a different, odourless gas produced by fuel-burning appliances, and it is potentially fatal. A device that measures one tells you nothing whatsoever about the other. Of the six monitors compared here, only the Amazon Smart Air Quality Monitor senses carbon monoxide at all — and Amazon's own customer documentation states it is not certified as a CO alarm or CO detector and is not a substitute for one. Its stated CO accuracy is ±5 ppm or ±30%, with a sensor baseline offset of under ±10 ppm, which in practice means it may register nothing at the low, sustained concentrations a certified EN 50291 alarm is specifically designed to catch. Whatever you buy from this page, a separate alarm marked EN 50291 is the thing that actually protects the household.
Read accuracy claims carefully, and be sceptical of badges that sound like credentials but are not. Aranet publishes an accuracy figure of ±(30 ppm + 3% of reading) for the NDIR CO2 sensor in the Aranet4 Home — that is a manufacturer specification rather than an independently certified one, and it should be read as the former. Elsewhere in this cluster you will meet "Calm Tech Certified" on the Airthings View Plus, which is a design accreditation concerned with how a device competes for your attention; ISO 27001, which Airthings holds as a company and which is an information-security management standard; and Apple Home compatibility on the Netatmo, which is a platform interoperability feature. None of the three says anything at all about measurement accuracy or safety. Allow for settling time too: Airthings states its CO2 and VOC readings need roughly seven days to stabilise, so treat the first week's numbers as the device finding its feet rather than as data to act on.
Radon deserves a calm, factual paragraph rather than an alarming one. It is a naturally occurring gas whose levels vary by geology, and UKHSA and GOV.UK publish radon-affected-area maps alongside testing guidance — that is the authority to consult if you are in an affected postcode. A consumer monitor such as the Airthings View Plus or Wave Plus gives an indicative continuous reading, which is genuinely useful for seeing how levels shift with the seasons and with ventilation, but it is not a substitute for a professional radon test. After that it comes down to practicalities, and those decide whether a monitor gets used at all. A screen means you glance at it in passing; app-only means you check it when you remember. Battery models keep reading during a power cut, while the mains-powered Netatmo and Amazon units simply stop. And Airthings' cheaper Wave models need a separate SmartLink hub, or a View-series monitor acting as one, before you get continuous remote access — which makes the real cost of ownership higher than the shelf price suggests.
Top pick: Airthings View Plus (2960) Radon & Indoor Air Quality Monitor. The only monitor here that measures radon, PM2.5 and CO2 together, and the only Airthings with a proper numeric display alongside the app and web dashboard. It has no carbon monoxide sensor, so it changes nothing about your need for a certified alarm. Airthings also states the CO2 and VOC readings take around seven days to settle, so judge it in week two rather than week one.
| Monitor | Measures | Display | Connectivity | Power | Price | |
|---|---|---|---|---|---|---|
| Airthings View Plus (2960) Radon & Indoor Air Quality MonitorTOP PICK | Radon, PM1/PM2.5, CO2, VOCs, temp, humidity, pressure. No CO. | 2.9in e-ink screen, plus motion-activated green/yellow/red glow | Wi-Fi 2.4GHz and Bluetooth; app and dashboard; USB-C hub mode | 6x AA, up to 2 years claimed, or continuous USB-C mains | £172.85at usual price | Check price → |
| Aranet4 Home Wireless Indoor CO2 & Air Quality Monitor | CO2 (NDIR), temp, humidity, pressure. No PM2.5, VOC, radon or CO. | Large-digit e-ink, readable across a room, traffic-light status | Bluetooth only — no Wi-Fi; Aranet Home app for history/export | 2x AA — up to ~4 years alkaline, up to 7 years on lithium | £159.00at usual price | Check price → |
| Airthings Wave Plus Radon & Indoor Air Quality Monitor | Radon, CO2, VOCs, temp, humidity, pressure. No PM2.5, no CO. | No screen — wave your hand for a red/yellow/green glow ring | Bluetooth to app; continuous sync needs a SmartLink hub (extra) | 2x AA — 16 months claimed, 18 months via SmartLink | £154.99at usual price | Check price → |
| Netatmo Smart Indoor Air Quality Monitor (NHC-UK) | CO2, temp, humidity, noise level. No PM2.5, VOC, radon or CO. | No screen — press the top for a colour-coded LED summary | Wi-Fi to the Netatmo app, with Apple Home compatibility | Mains only via USB adaptor — no battery, must stay plugged in | £67.99at usual price | Check price → |
| Amazon Smart Air Quality Monitor | PM2.5, VOCs (low/med/high), CO, humidity, temp. No CO2, no radon. | No screen — one status LED; all readings live in the Alexa app | Wi-Fi and Bluetooth; Alexa app, Echo voice readouts and routines | Mains USB only — no battery, so it stops in a power cut | £69.99at usual price | Check price → |
| Airthings Wave Mini Indoor Air Quality Monitor | VOCs, temp, humidity, calculated mould risk. No radon, CO2, PM2.5, CO. | No screen — wave your hand for a red/yellow/green glow | Bluetooth to app; SmartLink needs a View-series hub (extra) | 3x AA — over 2 years claimed, over 3 years via SmartLink | £75.00at usual price | Check price → |
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Who it's for: One device covering radon, particulates and CO2 in the same room, with a screen you can actually read.
The only monitor here that measures radon, PM2.5 and CO2 together, and the only Airthings with a proper numeric display alongside the app and web dashboard. It has no carbon monoxide sensor, so it changes nothing about your need for a certified alarm. Airthings also states the CO2 and VOC readings take around seven days to settle, so judge it in week two rather than week one.
- Seven sensors in one unit, including radon, PM1/PM2.5 and CO2
- 2.9in e-ink screen means you read it in passing rather than opening an app
- Runs on 6x AA for a claimed two years, or on USB-C mains as a SmartLink hub for Wave devices
- No carbon monoxide sensor at all — it is not, and cannot be, a CO alarm
- Airthings states CO2 and VOC readings need roughly seven days to settle, so early numbers mislead
- UK pricing swings from around £173 to £250 for the same unit depending on retailer
Don't buy if you only care about ventilation — the Aranet4 Home measures CO2 more accurately and costs less.
Who it's for: Knowing, from the other side of the room and without touching your phone, when to open a window.
The best CO2 instrument in this cluster by a clear margin, with a manufacturer-stated NDIR accuracy of ±(30 ppm + 3% of reading) and a display you can genuinely read across a room. It does one job properly and makes no pretence otherwise: no particulates, no VOCs, no radon and — this is the point readers most often get wrong — no carbon monoxide whatsoever. Bluetooth only, so there is no checking in on it while you are out.
- Manufacturer-stated CO2 accuracy of ±(30 ppm + 3% of reading) from an NDIR sensor
- Large-digit e-ink display with traffic-light status, readable from across a room
- 2x AA lasts years — up to around four on alkalines, up to seven on lithium cells
- CO2, temperature, humidity and pressure only — no PM2.5, VOC, radon or carbon monoxide
- Bluetooth only with no Wi-Fi, so no remote checking or alerts when you are out of range
- That accuracy figure is a manufacturer specification, not an independently certified one
Don't buy if you want particulates or radon as well — the Airthings View Plus covers all three at a broadly similar price.
Who it's for: Radon and CO2 monitoring in a home that already has, or is willing to add, an Airthings hub.
Radon, CO2 and VOC sensing for around £155 with a claimed 16-month battery life is a lot of measurement for the money. The catches are structural rather than minor: no PM2.5 sensor, no numeric screen, and no continuous cloud sync unless you buy a SmartLink hub or already own a View-series monitor — so remote alerts cost more than the headline price. Like every other Airthings here, it has no carbon monoxide sensor.
- Radon, CO2 and VOC sensing for around £20 less than the View Plus
- 2x AA lasts a claimed 16 months, or 18 months when connected via SmartLink
- Works with Alexa, Google Assistant, IFTTT and Homey, though not for radon readings
- No PM2.5 sensor, so cooking, wood smoke and traffic particles go unmeasured
- Remote access needs a separate SmartLink hub or a View-series monitor — a second purchase the headline price hides
- No numeric display, so every actual figure lives in the app rather than on the device
Don't buy if you want particulate readings or a screen — the View Plus adds both for a modest step up in price.
Who it's for: A cheap, permanently plugged-in CO2 reading in a room where noise levels are also worth knowing.
The cheapest genuine CO2 monitor here, and the only one that also measures noise — a real differentiator in a home office or a room next to a busy road. It is old hardware for the money, it has no screen, and it is mains-only, so it goes dark the moment the power does. Its "Asthmatic", "Baby" and "Family" app profiles are adjustable alert thresholds, not health features, and should not be read as anything more.
- Cheapest route to a real CO2 reading, from around £68 at the keenest UK sellers
- Noise-level sensing that nothing else on this page offers
- Wi-Fi straight to the app plus Apple Home compatibility, with no hub to buy separately
- Mains-only via USB adaptor with no battery, so it stops working in a power cut
- No screen — readings live in the app, with only a colour-coded LED on the device itself
- Apple Home compatibility is a platform feature, not a safety or accuracy credential
Don't buy if you want a CO2 figure you can read at a glance without your phone — the Aranet4 Home has the display for it.
Amazon Smart Air Quality Monitor
Who it's for: Particulate readings in an Alexa household, at a price that regularly drops a long way below list.
The only monitor here with a carbon monoxide sensor, which makes it the one most easily misread as a safety device. Amazon's own documentation states it is not certified as a CO alarm or detector and is not a substitute for one, and its stated CO accuracy of ±5 ppm or ±30% with a baseline offset under ±10 ppm means it may register nothing at the low, sustained levels a certified EN 50291 alarm exists to catch. As a cheap PM2.5 and VOC-trend sensor for an Alexa home it is fine; it measures no CO2 at all.
- Measures PM2.5, which most rivals near this price do not
- Alexa voice readouts and routines with no extra hub or bridge required
- List price £69.99 but discounted often and heavily — it has been seen around £39.99
- Not certified as a CO alarm and not a substitute for one, per Amazon's own documentation — you still need a separate EN 50291 alarm
- No CO2 measurement at all, so it is no help whatsoever with ventilation
- Mains-only with no battery and no screen: it stops in a power cut and every reading lives in the Alexa app
Don't buy if you are buying it for carbon monoxide protection — that job needs a dedicated alarm certified to EN 50291, which this does not replace.
Airthings Wave Mini Indoor Air Quality Monitor
Who it's for: A damp-prone bathroom, utility room or bedroom where humidity and airborne chemicals are the actual question.
This is a VOC-and-damp device rather than an air quality monitor in the general sense: no radon, no CO2, no particulates and emphatically no carbon monoxide. Its Mould Risk Indicator is a 0–10 score calculated from temperature and humidity, not a measurement of mould or spores. At around £75 it is the cheapest way into the Airthings app, but you are paying close to Aranet4 money for considerably less sensing.
- Cheapest route into the Airthings app, with proper history graphs
- 3x AA lasts a claimed two years-plus, or three years-plus via SmartLink
- Mould Risk Indicator condenses temperature and humidity into one number you can act on
- Measures the least of anything here — no radon, no CO2, no PM2.5 and no carbon monoxide
- The Mould Risk Indicator is calculated from temperature and humidity, not a mould or spore measurement
- No screen, and SmartLink access requires a View-series monitor acting as a hub
Don't buy if you want to know when to open a window — the Aranet4 Home measures CO2 and this does not.
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Common questions
Does an air quality monitor detect carbon monoxide?
Almost never, and never reliably enough to depend on. Five of the six monitors compared here have no carbon monoxide sensor at all — they measure CO2, particulates, VOCs or radon instead. The Amazon Smart Air Quality Monitor does include a CO sensor, but Amazon states it is not certified as a CO alarm or detector and is not a substitute for one. Every home with a fuel-burning appliance needs a dedicated alarm marked EN 50291, whatever monitor is also sitting in the room.
What is the difference between CO2 and CO?
Carbon dioxide (CO2) is what you breathe out. It builds up in unventilated rooms and is a good proxy for whether fresh air is getting in — high readings mean open a window, not evacuate. Carbon monoxide (CO) is a different gas, odourless and produced by fuel-burning appliances, and it is potentially fatal. They are one character apart in writing and nothing alike in practice: a CO2 monitor gives no warning of carbon monoxide.
Which monitor should I get if I just want to know when to open a window?
The Aranet4 Home. CO2 is the reading that answers that question, and the Aranet4 does it with a manufacturer-stated NDIR accuracy of ±(30 ppm + 3% of reading) on a large-digit display you can read from across the room. The Netatmo Smart Indoor Air Quality Monitor is the cheaper CO2 option if you are happy checking a phone app rather than glancing at a screen.
Do I need a monitor that measures radon?
It depends where you live. Radon levels vary by geology, and UKHSA and GOV.UK publish radon-affected-area maps and testing guidance — check those first. If you are in an affected area, a professional radon test is the proper way to establish your levels. A consumer monitor such as the Airthings View Plus or Wave Plus gives an indicative continuous reading that is useful for tracking how levels move with the seasons and with ventilation, but it does not replace that test.
Do these keep working in a power cut?
The battery-powered ones do. The Airthings models run on AA cells — six in the View Plus, two in the Wave Plus, three in the Wave Mini — and the Aranet4 Home uses two AAs, so all four carry on reading. The Netatmo and the Amazon monitor are mains-only via USB with no battery, so they stop the moment the power does. Bear in mind that the Wi-Fi models also lose their app connection when the router goes down, even if the device itself is still running on batteries.
Do I need Wi-Fi, or is Bluetooth enough?
Bluetooth is enough if you only want to read the device when you are stood near it — that is how the Aranet4 Home works, and it has no Wi-Fi at all. Wi-Fi matters if you want remote checking, cloud history or alerts while you are out; the Airthings View Plus, the Netatmo and the Amazon monitor all have it built in. The Airthings Wave Plus and Wave Mini sit awkwardly in between: both need a separate SmartLink hub, or a View-series monitor acting as one, before they will sync continuously, and that is an additional purchase.
Will a monitor help with asthma, allergies or damp?
A monitor measures conditions, it does not treat anything, and no device here should be understood as managing or preventing a medical condition — Netatmo's "Asthmatic", "Baby" and "Family" app profiles are adjustable alert thresholds and nothing more. What a monitor can do is show you the conditions you are living in so you can change them: ventilate when CO2 climbs, run the extractor when humidity stays high, work out what is producing particulates. The Airthings Wave Mini's Mould Risk Indicator is a 0–10 score calculated from temperature and humidity rather than a mould or spore measurement, but it is a fair prompt to deal with a damp room.