Short answer: Mount a carbon monoxide detector on the ceiling of the room with your central heating boiler, water heater or stove: centrally, 1 to 3 metres from the appliance and at least 30 cm from the wall. In bedrooms and other rooms where you spend a long time, mount one at breathing height. Never in the bathroom, behind curtains or next to a vent.
Our solution
Detect carbon monoxide, gas and smoke in time
The CarbonAlert warns you immediately when CO levels rise. See which detectors are available for carbon monoxide, gas and smoke, standalone or linked to your alarm system.
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What is carbon monoxide and where does it come from?
Carbon monoxide (CO) is a gas with no smell and no colour. It is produced by incomplete combustion of fuels such as gas, wood, oil and coal. You can't smell it, you can't see it and an ordinary smoke detector doesn't respond to it. That is why a separate carbon monoxide detector is the only way to notice it in time.
In the home, the risk lies mainly with combustion appliances: the central heating boiler, a gas water heater, a gas heater or gas fireplace, and also a wood stove or open fire. If something goes wrong with the combustion, the flue or the ventilation, CO can build up in the home. The Dutch government therefore advises having appliances serviced by a certified company and mounting a carbon monoxide detector; the Dutch Burns Foundation (Brandwonden Stichting) recommends an annual check.
In which rooms should you put a carbon monoxide detector?
The advice of the Dutch National Institute for Public Health and the Environment (RIVM, in the Dutch GGD guideline on carbon monoxide) and the Dutch Burns Foundation distinguishes two kinds of rooms:
- The room with the combustion appliance. That's where the gas is produced, so that's where you want to notice it first. Think of the attic or utility room with the boiler, or the living room with the gas fireplace or wood stove.
- Rooms where you spend a long time. Especially bedrooms: someone who is asleep won't notice the first symptoms. Depending on the layout of your home, a detector in the living room or study can also be sensible.
One exception: the bathroom. No detector goes there. If there is a water heater, heater or boiler in the bathroom, mount the detector in the adjoining room at breathing height. If that's the landing, at head height when standing; if the bathroom opens onto a bedroom, at pillow height.
At what height and distance should you mount it?
The height depends on the room. Near the appliance, the detector goes high: carbon monoxide is fractionally lighter than air and spreads through the room from the source. In rooms without an appliance, you mount it at the height where you breathe.
| Room | Location | Distance |
|---|---|---|
| With combustion appliance | On the ceiling, in the centre of the room | 1 to 3 metres horizontally from the appliance, at least 30 cm from the walls |
| With appliance and sloping ceiling | On the sloping ceiling | 1 to 3 metres horizontally from the appliance |
| Bedroom | At breathing height: pillow height | Not behind curtains or cupboards |
| Living room or study without appliance | At breathing height: sitting or standing height | Not next to an air inlet or outlet |
| Bathroom with appliance | Not in the bathroom, but in the adjoining room at breathing height | Not behind objects or next to a vent |
Note the difference with a smoke detector: that always goes on the ceiling. If you want to know exactly where smoke detectors belong, read which smoke detectors the Dutch fire brigade recommends.
Where should you not put a carbon monoxide detector?
A detector in the wrong place measures the gas too late or not properly. So avoid:
- a spot right above or next to the appliance: keep 1 to 3 metres away;
- a corner or right against the wall: leave at least 30 cm clear;
- the vicinity of ventilation grilles, cooker hoods, windows and other air inlets or outlets;
- behind curtains, in a cupboard or behind furniture;
- right next to lamps or other objects on the ceiling;
- the bathroom.
In the room with the boiler, water heater or stove, the detector goes on the ceiling: in the centre of the room, between 1 and 3 metres from the appliance and not close to a vent or in a corner. That way it measures the gas before it spreads through the whole house.
How do you recognise carbon monoxide poisoning?
The symptoms resemble flu and occur mainly in the heating season, which makes them treacherous. Mild poisoning involves headache, dizziness, nausea, vomiting and blurred vision. With more exposure, confusion, fainting, chest pain, shortness of breath and muscle weakness are added.
What do you do when the detector goes off?
The Dutch fire brigade (Brandweer Nederland) and the Dutch Burns Foundation give three steps:
- Warn the other people in the house.
- Go outside immediately.
- Call 112.
Only use the appliance again after a certified installer has checked it. You may not work on gas combustion appliances yourself: according to the Dutch government, a certified company must do that.
Which detector do you need: CO, gas or smoke?
Carbon monoxide, natural gas and smoke are three different hazards, and each requires its own detector. At Neroo, these are the options:
- CarbonAlert is the carbon monoxide detector. It warns immediately when CO levels rise and runs on a long-life battery. With the Wi-Fi version, you also get the alert on your smartphone when you're not at home.
- GasRadar doesn't measure carbon monoxide, but flammable gases such as methane (natural gas), propane and butane. It runs on mains power, has a display and a built-in siren, and links to your ShieldLink® alarm system, so you also get a notification on your phone in case of a gas leak.
- SmokeAlert and SmokeSense are smoke detectors. You link the SmokeAlert Link and the SmokeSense to your Neroo alarm system, so that when there is smoke the whole system raises the alarm and you get a notification with the name of the room. The SmokeAlert One works standalone via Wi-Fi.
Do you have a motorhome, caravan or boat with a gas heater or cooker on board? The same principle applies: a carbon monoxide detector in the space where you sleep and spend time.
So where do you put a carbon monoxide detector?
On the ceiling of the room with the combustion appliance, centrally and 1 to 3 metres from the appliance, and also at breathing height in bedrooms and other rooms where you spend a long time.
Our solution
Detect carbon monoxide, gas and smoke in time
The CarbonAlert warns you immediately when CO levels rise. See which detectors are available for carbon monoxide, gas and smoke, standalone or linked to your alarm system.
View the options
Frequently asked questions
How many carbon monoxide detectors do you need?
At least one in every room with a combustion appliance, such as a boiler, water heater, gas heater or wood stove. In addition, a detector at breathing height in bedrooms and other rooms where you spend a long time is sensible. The exact number depends on the layout of your home.
Can a carbon monoxide detector go in the bathroom?
No. If there is a water heater, heater or boiler in the bathroom, mount the detector in the adjoining room at breathing height, for example at head height on the landing or at pillow height in a bedroom.
Is a carbon monoxide detector mandatory?
Not in an ordinary home in the Netherlands: the Dutch statutory detector requirement that has applied since 1 July 2022 concerns smoke detectors. The Dutch government does advise mounting a carbon monoxide detector if you have a boiler, water heater, gas heater or fireplace.
Can a smoke detector also measure carbon monoxide?
No, an ordinary smoke detector responds to smoke and not to carbon monoxide. Combined smoke and CO detectors exist; according to the Dutch RIVM, they are suitable in a room with a combustion appliance, because both detectors belong on the ceiling there. Elsewhere you need two separate detectors.
What should you do if the carbon monoxide detector goes off?
Warn the other people in the house, go outside immediately and call 112. Only use the appliance again after a certified installer has checked it.
Sources and references
- RIVM (Dutch National Institute for Public Health and the Environment), GGD-richtlijn medische milieukunde Koolmonoxide: Voorlichting over koolmonoxiderisico’s door verbrandingstoestellen — accessed September 2026
- Nederlandse Brandwonden Stichting (Dutch Burns Foundation), CO-melders — accessed September 2026
- Brandweer Nederland and Nederlandse Brandwonden Stichting (CO-wijzer), Waar plaats ik een CO-melder? — accessed September 2026
- Brandweer Nederland and Nederlandse Brandwonden Stichting (CO-wijzer), Wat zijn de symptomen van een CO-vergiftiging? — accessed September 2026
- Rijksoverheid (Dutch government), Hoe voorkom ik koolmonoxidevergiftiging in mijn huis? — accessed September 2026
- Consumentenbond (Dutch consumer association), Koolmonoxide melder in huis — accessed September 2026
