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Gas detector buying guide

Updated: 20 October 2026

You are in a UK kitchen on mains gas, or next to an LPG bottle in a caravan, and the amazon.co.uk results all wear the same name. Some are pens that switch off after a few minutes. Some are alarms you leave powered. One model in this set only reads oxygen. This gas detector buying guide puts the decision in order: the job, the fuel, the claims on the listing, then the plug. The [gas detector](/hub/fire-protection/gas-detector) comparison holds the product table. Prices and star counts below come from those amazon.co.uk listings, noted by the Products Compared editorial team on 20 October 2026, and they are not a lab test.

You are in a UK kitchen on mains gas, or next to an LPG bottle in a caravan, and the amazon.co.uk results all wear the same name. Some are pens that switch off after a few minutes. Some are alarms you leave powered.

Our top picks

TopTes TopTes PT199

Best overall

TopTes TopTes PT199
7.0/10about £22.99
View offer
Firlarm Firlarm BRJ-502

Best value

Firlarm Firlarm BRJ-502
8.3/10about £18.66
View offer
ABUS ABUS GWM100ME

Rank 3

ABUS ABUS GWM100ME
9.5/10about £53.45
View offer
On this page
  1. 1.Name the job before the brand
  2. 2.Name the gas, then the power
  3. 3.Claims and numbers that do not travel
  4. 4.What the detector will not do

Name the job before the brand

A battery pen that switches off after about five minutes is a check tool you use at a joint, then put away. A plug-in or corded alarm is the leave-on job. The Guard-756, at about £79.99, is a third job: an oxygen monitor. It will not stand in for a combustible-gas alarm. In this batch, basic pens and plug-ins sit at about £14 to £20, the middle of the set at about £23 to £40, and the ABUS, the S2 Multi and the oxygen monitor at about £53 to £80. These bands describe this batch only. The ABUS GWM100ME at about £53.45 is still the wrong buy if you only needed a five-minute check. Stars come last. The PT199 shows 4.6 from 8,415 ratings. Three Neoteck colours each print 4.6 from 1,320 and share opening review text, so that is one parent figure.

Name the gas, then the power

Mains natural gas is mostly methane, and it rises. LPG vapour from a caravan bottle is heavier than air, and it sinks. A skirting socket is a poor place for a natural-gas alarm, which UK review text on the Firlarm and D MODUN listings says in plain words, because that gas collects higher in the room. Height for each fuel is on the natural gas or LPG detector page. After the fuel, check the power. In this batch only the D MODUN states a British plug. The ABUS GWM100ME states AC 220–240 V and an EN50194-1 line on the highlight, at about £53.45. That line is a claim on the ABUS listing, not evidence that cheaper plug-ins meet the same standard. UK mains are 230 V with a BS 1363 plug, so check the photos.
TopTes TopTes PT199

Testsieger

TopTes TopTes PT199
7.0/10about £22.99
View offer

Claims and numbers that do not travel

Read the bullets, not the category heading. Only the TopTes S2 Multi bullets in this batch state a carbon monoxide channel beside combustible gas, at about £79.99. The Firlarm bullet says that unit cannot detect carbon monoxide, and that the alarm starts over 3 percent LEL. Treat both as seller text, not a bench result. YOJOCK’s item-type line mentions CO and smoke. The bullets do not, so that heading is not a carbon monoxide feature and it is not a smoke alarm. Percent LEL and ppm do not travel cleanly between brands, and a lower ppm figure is not a sharper sensor.

What the detector will not do

A detector tells you something has changed. It does not shut a valve or make a joint sound. Health and Safety Executive domestic gas guidance is that a detector does not replace the emergency call or a Gas Safe registered engineer. If you smell gas, phone 0800 111 999 and keep away from switches. If a reading climbs, or anyone feels dizzy or sick, stop before anyone undoes a fitting, and get a Gas Safe registered engineer. People who cannot rely on the odourant still need that service. Cadent tells people with little sense of smell to fit a natural gas detector and to join the Priority Services Register, and a yearly Gas Safe service remains.

Common questions

Is a battery pen enough if the house is on mains gas?
A battery pen is enough for a short check at a joint while you hold it, for the gas that sensor is built to see. It is a weak sole warning in a house you leave, because it switches off after about five minutes. Compared with a plug-in alarm, the pen is the check tool. If you cannot smell the odourant, a fitted detector is the closer match, and a yearly Gas Safe service still applies.
Does BS EN 50194-1 apply to a five-minute pen?
BS EN 50194-1:2023 covers apparatus that runs continuously in a fixed household installation. A five-minute pen is outside that scope. The EN50194-1 line in this set is on the ABUS GWM100ME highlight at about £53.45, and it does not certify the other plug-ins or the pens. The standard does not require every gas home to own a detector.
Can I compare percent LEL and ppm across brands?
These figures are not one shared test. The PT210S listing pairs 100 ppm with 1 percent LEL. A usual methane lower explosive limit is about 5 percent by volume, so 1 percent LEL is about 500 ppm. That is a rule of thumb, not a lab result, and a smaller ppm number is not a better sensor. Keep the Firlarm line, alarm over 3 percent LEL, inside that listing.
Does plug-in mean a British BS 1363 plug?
Only the D MODUN in this batch states a British plug. The ABUS GWM100ME states AC 220–240 V, which suits UK mains at 230 V, though voltage is separate from the pin shape. Other listings say plug-in and do not print BS 1363, so check the photos. A Schuko-only plug is a UK fitting problem even when the alarm matches your gas.
Will a combustible-gas detector also warn about carbon monoxide?
Only when the bullets say so. Only the TopTes S2 Multi bullets here state a carbon monoxide channel beside combustible gas. The Firlarm bullet says that model cannot detect carbon monoxide. YOJOCK’s item-type line mentions CO and smoke, and the bullets do not. A combustible-gas alarm is a different duty from an England landlord carbon monoxide alarm.
What should I buy if I cannot smell gas?
Cadent tells people with little sense of smell to fit a natural gas detector and join the Priority Services Register. A leave-on alarm is the closer match, compared with a five-minute pen, though the sensor still has to match the fuel. A yearly Gas Safe service remains. The detector warns you and does not replace 0800 111 999 if you suspect a leak.

Related pages

Best gas detector

Gas detector vs carbon monoxide alarm

Gas detector

How to check a gas leak before phoning the engineer

Natural gas or LPG detector: methane rises, LPG sinks

Sources

Safety rules and standards are from the public sources below. Prices, stars, and review counts are from the amazon.co.uk listings. Last checked 20 October 2026.

  1. National Gas emergency contacts (retrieved 20 October 2026)
  2. HSE domestic gas FAQs (retrieved 20 October 2026)
  3. Gas Safety (Installation and Use) Regulations 1998 (retrieved 20 October 2026)
  4. HSE L56, safety in the installation and use of gas systems and appliances (retrieved 20 October 2026)
  5. GOV.UK smoke and carbon monoxide alarm booklet for landlords (retrieved 20 October 2026)
  6. BSI BS EN 50194-1:2023, flammable gases in household premises (retrieved 20 October 2026)
  7. Cadent, sense of smell (retrieved 20 October 2026)
  8. Safelincs: will a carbon monoxide alarm detect gas leaks? (retrieved 20 October 2026)