Tent Heaters and Carbon Monoxide Safety (2026)

Cold-weather campers, hunters and ice anglers who pack a propane heater are caught between two sets of instructions: the maker of "indoor safe" heaters lists tents as a use, and the federal agencies that count carbon monoxide deaths say never. Both are quoted below, followed by the alarm we would carry and the one rule we would not bend.

How we chose: we did not test these heaters or alarms; we read Mr. Heater's spec sheets, the CDC's and CPSC's carbon monoxide guidance and the CPSC's own lab report on camp heaters, and kept only products sold by Amazon.com and in stock on September 29, 2026.

Two alarms and two heaters side by side

Prices are Amazon's, as of the time shown, and subject to change. Details

Buy the alarm first. It is the only item in this table that tells you carbon monoxide is present.

What the CDC and CPSC say about heaters in tents

The CDC's rule is flat. After two 1999 camping incidents in Georgia killed six people, a propane stove in a sealed tent and a charcoal grill in a zipped tent, its report said camping stoves, camping heaters, lanterns and charcoal grills "should never be used inside a tent, camper, or other enclosed shelter." It added: "Opening tent flaps, doors, or windows is insufficient."

The CPSC's camping safety alert says: "Do not use portable heaters or lanterns while sleeping in enclosed areas such as tents, campers, and other vehicles." It calls this "especially important at high altitudes, where the risk of carbon monoxide poisoning is increased," and counts at least 26 deaths linked to camping equipment from 2006 to 2010.

Stove makers print the same thing on their own gear. MSR's PocketRocket Deluxe instructions read: "Never use this stove in an enclosed space such as a camper, tent, car, or home."

What Mr. Heater says, and where it differs

Mr. Heater sells the Buddy line as indoor safe. Its Portable Buddy page calls the MH9BX an "indoor safe radiant propane heater" and lists tents and campers among its uses, alongside workshops, porches and hunting blinds. The spec table gives a maximum elevation of 7,000 feet.

Mr. Heater's own Buddy series page adds the fine print: the heaters are "restricted from all indoor use in Massachusetts and Canada" and "restricted from use in dwellings in California." It cites Canadian and Massachusetts law against unvented heaters indoors.

So the maker permits what the CDC says never to do. We follow the stricter rule. No fuel-burning heater runs inside a tent we sleep in, and none runs unattended. That leaves the Buddy for what it does well: warming people who are awake, in open air or an open-sided shelter.

An oxygen sensor is not a carbon monoxide alarm

The ODS on a Buddy heater watches oxygen. The CPSC's 2002 lab report, CO Emissions From Portable Propane Radiant Heaters, tested eight camp heaters in a 100 cubic foot chamber. The two with an ODS shut off when oxygen fell to between 18.8 and 19.6 percent, which kept CO under 100 ppm in that test.

The six heaters without an ODS did not. Their steady-state CO peaked between 260 and 2,124 ppm. The same report investigated 12 incidents from 1996 to 2001 involving these heaters: 18 deaths, all in tents, campers, trailers or vehicles.

Read those numbers both ways. An ODS heater is much safer than one without, in a lab chamber, when it works. It still cannot tell you about CO from anything else burning nearby, and it is one sensor you cannot test at camp.

Which CO alarm, and where it goes

The CDC's carbon monoxide page asks for "battery-operated or battery back-up CO detectors near every sleeping area," batteries checked each spring and fall, and replacement "following the manufacturer's instructions or every 5 years." On a trip, that means a battery alarm where people sleep: the camper, the cabin, the truck cab.

Buy the Kidde portable alarm if you want one alarm that moves between the house, the camper and the gear bin. It runs on two AAs, sits on a table, and its Event Memory shows when it last detected CO or was tested.

Buy the First Alert 10-year alarm if you want a number. First Alert's CO710 page lists it to UL 2034, and the display shows CO concentration with a peak-level memory. The sealed battery means no battery to forget, and the whole alarm is replaced at end of life.

A CO alarm is a backstop, not a permission slip. It does not make a heater in a closed tent safe; it tells you something has already gone wrong.

Heaters we would buy, and how we would use them

Buy the Portable Buddy for heat you sit in front of: a picnic table on a cold morning, a hunting camp's open-sided kitchen, a workshop with the door open. Mr. Heater rates it at 4,000 or 9,000 BTU and about 225 square feet. Keep it upright, away from fabric, and below its 7,000 ft limit.

Buy the Little Buddy if 3,800 BTU is enough, such as for warming your hands at an ice hole on open ice. The listing gives a tip-over shutoff and low-oxygen shutoff, and Mr. Heater's Little Buddy page lists 5.6 hours on one 1 lb cylinder.

Warmth in the tent comes from what you sleep in. A bag rated to the night's low on its ISO comfort rating and a pad with enough R-value do the job without burning anything.

Related: hand warmers, disposable vs rechargeable, our winter camping checklist.

Heater recalls on record

Our recall database, built from CPSC notices since 2023, shows no recall of the Buddy heaters listed here. It does show one from the same company: in April 2025, Enerco, which registers Mr. Heater warranties, recalled about 21,250 DEWALT 70,000 BTU forced-air propane heaters sold at Lowe's, for fire and burn hazards. Those are outdoor jobsite heaters, not Buddies.

If someone feels sick

The CPSC lists the symptoms as "headache, dizziness, weakness, nausea, vomiting, sleepiness, and confusion," and warns that alcohol and drugs can make them harder to recognize. Turn the heater off and get everyone into fresh air. The CPSC says to see a doctor if anyone develops cold or flu-like symptoms while camping.

Frequently Asked Questions

Can I run a Buddy heater in my tent if I crack a window?

The CDC says no: its 1999 camping report found that "opening tent flaps, doors, or windows is insufficient to prevent build-up of CO concentrations" from fuel-burning devices. Mr. Heater permits tent use in ventilated spaces, but we follow the agency.

Does the heater's low-oxygen shutoff work at altitude?

Mr. Heater limits both Buddy heaters on this page to 7,000 feet in their spec tables. Above that, leave the heater at home.

Are propane heaters allowed indoors everywhere in the US?

No. Mr. Heater says its Buddy heaters are restricted from all indoor use in Massachusetts and from use in dwellings in California, where unvented heaters are regulated.

How often should I replace a CO alarm?

Follow the maker: the CDC says to replace one per the manufacturer's instructions or every 5 years. First Alert's CO710 has a sealed 10-year battery and a 10-year limited warranty, and chirps at end of life.