Carbon monoxide in a van: staying safe when heating and cooking in a small space

A camper van has very little air volume, and everything that burns inside it releases its exhaust into that same air. Anyone who sleeps, cooks and heats in a few cubic metres should know how carbon monoxide forms, how to notice it and which habits prevent it.

Why carbon monoxide is so dangerous

Carbon monoxide (CO) is produced by incomplete combustion, for example in heaters, stoves, grills and engines. The US health agency CDC describes it as a colourless, odourless gas that can kill without warning. Typical signs are headache, dizziness, weakness, nausea, vomiting, chest pain and confusion. Someone who is asleep or has been drinking may not notice them before losing consciousness. According to the CDC, infants, older people and people with heart or breathing problems are at particular risk.

What never belongs inside the van

Grills, charcoal and portable gas stoves do not belong in a closed van, tent or awning; the CDC says never to burn charcoal indoors or use a portable gas camp stove indoors. The UK NHS names barbecues and camping stoves used indoors, and running vehicle engines in enclosed spaces, as causes of poisoning. Generators run outdoors: for houses the CDC advises more than 20 feet (about 6 metres) from windows, doors and vents. The built-in hob is not a heater either: the CDC warns against heating a house with a gas oven, and an open flame releases combustion products, including CO, into the room.

When cooking, open a roof vent or a window, switch on an extractor if there is one, and keep the vents in the gas locker and the floor clear. Forced ventilation must never be blocked. How much air is enough depends on the vehicle, and if in doubt the manufacturer’s instructions apply.

Heating in the van

Fixed heaters are built to run inside a vehicle, but only as long as the exhaust is routed tightly to the outside. According to promobil, CO is also produced by the on-board heater and the absorption fridge; it is normally led outside through a pipe and flue, but can enter the living space if something is damaged. Check the exhaust route and connections for visible damage and a firm fit. Truma’s manual for its Combi heater has the gas installation checked by a qualified specialist according to national rules (every two years in Germany) and says never to use LPG appliances while refuelling, in multi-storey car parks, in garages or on ferries.

The same principles apply to diesel heaters: exhaust and combustion air are routed outside, the openings must be clear and the pipe tight. The sources opened here give no cross-manufacturer rules, so the instructions for your own unit are what count. Never run the heater in a closed garage.

Do not run the engine for heat while someone is asleep in the vehicle. That exhaust can also reach the cabin outdoors through leaks or a blocked tailpipe is plausible, but not specifically documented in the sources opened here. The danger in enclosed spaces is documented: the CDC warns against running a car in a garage even with the door open. If you are cold, a warmer sleeping bag or a properly checked heater is the better choice.

Alarms and detectors

A CO alarm does not replace caution, but it is the last line of defence. For leisure vehicles the relevant standard is EN 50291-2. It covers electrically operated CO detectors for continuous operation in motorhomes and similar premises, including boats. Type B gives visual and audible alarms, type A also gives signals that can switch appliances off.

On mounting: according to promobil, CO is about as heavy as air and spreads evenly through the room, so unlike propane it does not sink to the floor. For homes, the CDC recommends alarms near every sleeping area. Height and distance from the hob, heater and vents are set by the alarm’s instructions. On batteries, the CDC advises checking them when the clocks change and replacing alarms every five years; follow your unit’s instructions if they differ.

Propane and butane are heavier than air. According to promobil, LPG detectors are therefore mounted low, and combination units often work with external sensors at different heights. Check your manual for when to close the gas supply at the cylinder, for example when you leave the vehicle or at night. If you smell gas, Truma’s manual describes the steps: avoid ignition sources, open windows and doors, get everyone out of the vehicle, close the cylinders or shut off the gas supply from outside, and have an expert check the system before you use it again. In Germany, leisure vehicles with a fixed LPG system have had to pass a gas inspection (DVGW G 607) every 24 months since 19 June 2025, according to TÜV Nord.

Smoke alarms and fire extinguishers belong in the vehicle as well. The US National Park Service notes that many investigated RV fires had no smoke alarm or a non-working one, and advises testing it before departure. It recommends three extinguishers: one in the kitchen, one in the bedroom and one outside in an unlocked compartment or in the tow vehicle. What matters is that the extinguisher can be reached without a detour, that everyone knows where it is, and that there are two ways out.

When the alarm sounds or symptoms appear

Switch off all appliances, close the gas supply, open the door and windows and get everyone, people and pets, outside. The NHS notes that symptoms can come and go and often ease outdoors; do not go back in until the vehicle has been checked. With confusion, shortness of breath, chest pain, weakness or loss of consciousness, call emergency services at once (112 in Europe, 911 in the US). Even with mild symptoms, seek medical advice.

Standards and deadlines differ from country to country, and not every rental vehicle is equipped the same way. At pick-up, ask about the CO alarm, smoke alarm and extinguisher, test the alarms and, if in doubt, bring your own battery-powered CO alarm.

Sources

• Carbon monoxide: about CO and prevention (CDC)
• Carbon monoxide poisoning (NHS)
• Gaswarner im Mobil: Schutz vor unsichtbaren Gasen (promobil)
• EN 50291-2:2019, CO detection apparatus for recreational vehicles (Genorma)
• Truma Combi 4 / 6 E Gebrauchsanweisung (Truma, Kopie bei emr-campers.de)
• Fire Prevention 52: RV Fire Safety 101 (US National Park Service)
• Gasprüfung für Wohnwagen und Wohnmobile (TÜV Nord)