Carbon Monoxide in Camper Vans and RVs: Sources, Symptoms and Alarms
Carbon monoxide is an invisible, odorless gas made by diesel heaters, propane heaters and gas stoves. Any camper with one needs a CO alarm: UL 2034 in the US, EN 50291-2 for RVs in Europe and the UK. If it sounds, switch the appliance off if safe, get outside and seek medical help.
On this page (8)
- Where does carbon monoxide come from in a camper?
- What are the symptoms of carbon monoxide poisoning?
- What should I do if the CO alarm goes off?
- Which CO alarm standard should I look for?
- Battery alarm or 12 V combo alarm?
- Where should I fit the CO alarm?
- How do I make my camper CO-safe?
- Which CO detector should I buy?
Carbon monoxide (CO) is an invisible, odorless gas produced whenever fuel burns, and in a camper van or RV it comes mainly from diesel heaters, propane heaters and gas stoves. Any rig with one of these needs a CO alarm. In the US, look for UL 2034; in Europe and the UK, EN 50291-2. If the alarm sounds, switch the appliance off if it is safe to do so, get outside into fresh air and seek medical help.
This guide covers where CO comes from, how to recognize poisoning, which alarm to fit and a checklist to make your rig safer.
Where does carbon monoxide come from in a camper?
From every appliance that burns fuel inside or next to the living space. A small, closed cabin lets CO build up quickly. The table lists the usual sources and the key rule for each.
| Source | How CO gets in | Key rule |
|---|---|---|
| Fixed diesel air heater | Leaking or badly routed exhaust | Combustion air intake and exhaust outside the vehicle; exhaust pipe sealed and away from windows and air intakes |
| All-in-one portable diesel heater | The box or its exhaust left inside | Keep the box outside (or route the exhaust outside) and duct only warm air in; never with the exhaust inside |
| Propane (gas) heater | Burns cabin oxygen and releases CO and water vapor | Only models the maker calls indoor-safe have a low-oxygen sensor and tip-over shutoff, and they still need ventilation |
| Gas stove | Combustion products released into the cabin | Ventilate while cooking; keep a CO alarm in the rig |
| Engine exhaust | Fumes drifting in while idling or parked close to other vehicles | Do not rely on doors and vents to keep them out |
On propane heaters, the Mr. Heater Portable Buddy manual asks for a fresh-air opening of at least 9 square inches (about 58 cm²) (Mr. Heater Portable Buddy manual). Our view is simple: do not sleep with a propane heater running, and always keep a CO alarm on.
Diesel heaters are safer by design because they burn fuel in a sealed chamber and heat cabin air through a heat exchanger. That only holds if the installation is right. Read how to install a diesel heater before you drill anything.
What are the symptoms of carbon monoxide poisoning?
According to the NHS, the main symptoms are headache, dizziness, feeling or being sick, weakness, tiredness and confusion, chest and muscle pain, and shortness of breath (NHS, carbon monoxide poisoning). They are easy to confuse with a cold, a hangover or altitude.
Be suspicious when symptoms ease after you leave the rig, or when several people or pets feel unwell at once. You cannot smell or see CO, so an alarm is the only reliable warning.
What should I do if the CO alarm goes off?
Act first and investigate later. Follow these steps, based on the NHS advice:
- Switch off the heater, stove or engine, but only if you can do it safely and quickly.
- Get everyone outside into fresh air, including pets. Open doors on your way out if it takes no extra time.
- Get medical help, especially if anyone has symptoms. Tell them you suspect carbon monoxide.
- Do not go back in until the rig has been aired out and the cause is found.
- Have the appliance checked before you use it again. A false alarm is possible, but treat every alarm as real.
Which CO alarm standard should I look for?
In the US, UL 2034; in Europe and the UK, EN 50291-2, the part written for recreational vehicles. EN 50291-2 adds movement and vibration tests for caravans, motorhomes and boats, while EN 50291-1 covers homes (Safelincs, British Standards for CO alarms).
Read the listing carefully. Some state only “UL listed” or “UL Certified” without naming the standard; check the label or packaging. Several 12 V RV combo alarms on Amazon cite no standard at all.
| Feature | Why it matters |
|---|---|
| Declared standard (UL 2034 / EN 50291-2) | Evidence the alarm was tested to a known benchmark |
| Electrochemical sensor | The sensor type used for CO in the certified alarms in our catalog |
| Sealed 10-year battery or 12 V wiring | No flat battery at the worst moment |
| Digital display | Shows the CO level, not only an alarm |
| Propane (LP) detection | Useful in RVs with a propane system |
Battery alarm or 12 V combo alarm?
Both work; many RV owners use one of each. A battery alarm runs on its own, whatever state your house battery is in. A hardwired 12 V CO/LP alarm also detects propane and is usually flush-mounted where the old unit was.
The trade-off is power. A hardwired alarm only works while its 12 V supply is on. If you switch off the house battery in storage or overnight, a battery alarm keeps watching. For a van without propane, a certified battery CO alarm is the simplest choice.
Where should I fit the CO alarm?
Where the manufacturer’s manual says, in the living and sleeping area. Mounting height and distance from appliances differ between models, and combo alarms have their own rules for the propane sensor. Follow the manual rather than a generic rule.
A few practical points apply to every alarm:
- Keep it where you will hear it while asleep.
- Do not cover it with curtains, bedding or clothes.
- Press the test button regularly and before each trip.
- Replace it at the end of life the maker states.
How do I make my camper CO-safe?
Work through this checklist once, then repeat the quick checks before each trip.
- List every combustion appliance: diesel heater, propane heater, stove, generator or engine you run while parked.
- Check the diesel heater installation: intake and exhaust outside, exhaust sealed and away from windows and air intakes. See our diesel heater installation guide.
- Choose the right propane heater, if any: only an indoor-rated one with a low-oxygen sensor, used with ventilation and switched off at night. Compare options in the best propane heaters.
- Fit a CO alarm with a declared standard, and a combo CO/LP alarm if you carry propane.
- Ventilate while cooking with a roof vent fan or a window open. See the best RV roof vent fans.
- Test the alarm before every trip and replace batteries or units on time.
Which CO detector should I buy?
For most vans, a battery CO alarm with a declared UL certification, an electrochemical sensor and a sealed battery. The Kidde C3010D ticks those boxes on its listing, with a 10-year battery and a display. If you carry propane, add a 12 V CO/LP combo such as the Sponiwelly DE201, bearing in mind that its listing cites no standard.
Our full ranking of the best RV carbon monoxide detectors compares six models. For the bigger picture on insulation and safety gear, see insulation and safety.
Frequently asked questions
Can a diesel heater cause carbon monoxide poisoning in a van?
Yes, if exhaust gets inside. The combustion air intake and the exhaust must both be outside the vehicle, with the exhaust pipe well sealed and away from windows and air intakes. A CO alarm warns you if something fails.
Is it safe to sleep with a propane heater on in a camper?
Our advice is no. Propane heaters use the oxygen inside and produce CO and water vapor. Even indoor-rated models with a low-oxygen sensor need ventilation, so switch them off before you sleep and keep a CO alarm on.
What are the first symptoms of carbon monoxide poisoning?
According to the NHS: headache, dizziness, feeling or being sick, weakness, tiredness and confusion, chest and muscle pain, and shortness of breath. If several people or pets feel unwell at once, suspect CO.
Which CO alarm standard should I look for in an RV?
In the US, UL 2034. In Europe and the UK, EN 50291-2, the part written for caravans, motorhomes and boats with movement and vibration tests. EN 50291-1 is the version for homes.
Is a combined CO and propane alarm enough?
It covers both gases on one 12 V unit, which suits RVs with a propane system. Check which standard the listing declares. Several 12 V combo alarms on Amazon cite none, so pair one with a certified battery CO alarm.