Propane heat
Best Indoor-Safe Propane Heaters
Propane is the fastest, cheapest way to put real heat into a tent, cabin, or camper. The trick is buying a heater built for indoor use, ideally with an oxygen sensor and a tip-over shutoff, and then running it the right way: fresh air in, a CO alarm watching the room. Below are our top indoor-safe picks plus the buying logic and safety rules that keep this kind of heat from becoming a hazard.
Quick picks
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Mr. Heater Portable Buddy
Fast, simple, indoor-safe radiant heat for most people.
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How the heaters compare
| Heater | Best for | Output | Heats up to |
|---|---|---|---|
| Most people | 4,000 to 9,000 BTU | 225 sq ft | |
| Larger rooms | Up to 18,000 BTU | 450 sq ft | |
| Quiet RV heat | 3,200 to 6,000 BTU | 230 sq ft | |
| Larger RVs | 4,200 to 8,000 BTU | 290 sq ft | |
| Safety pairing | Detector, not a heater | Living spaces, not RVs |
The picks in detail
Our top indoor-safe propane heaters
Mr. Heater MH9BX Portable Buddy
Output: 4,000 to 9,000 BTUHeats: Up to 225 sq ftSafety: ODS + tip-over shutoffFresh air: 9 sq in minimum
The Portable Buddy is the default pick for good reason. Mr. Heater bills it as the most popular portable propane heater in North America, and it earns that with fast radiant heat, an oxygen depletion sensor, a tip-over shutoff, and dead-simple one-cylinder operation. It runs about three hours on high or up to six on low from a single 1 pound cylinder, and you can hook it to a 20 pound tank kept outdoors with a hose and filter for far cheaper hours. For a tent, ice shanty, truck cap, or small cabin, this is the easy answer. Mr. Heater's manual sets the limits: use it inside only where there is a window or roof vent, give it at least 9 square inches of fresh-air opening, never run it while sleeping or unattended, and expect it may shut off above 7,000 feet.
What we like
- Rated for indoor use in vented spaces, with an oxygen sensor
- Fast directional radiant heat
- Cheap to buy and simple to run
Worth knowing
- 1 pound cylinders get expensive fast
- Radiant heat warms a direction, not a whole room
Mr. Heater MH18B Big Buddy
Output: 4,000 / 9,000 / 18,000 BTUHeats: Up to 450 sq ftSafety: ODS + tip-over shutoffFresh air: 18 sq in, high and lowFan: Varies by unit, check the listing
When one Buddy cannot keep up, the Big Buddy steps in. Three heat levels, plus a fan on units that have one, push warmth across a real room, so it handles larger cabins, big tents, and workshops up to about 450 square feet. It runs on two 1 pound cylinders or a 20 pound tank by hose, up to roughly eleven hours on the dual setup. The same oxygen sensor and tip-over shutoff carry over. The fan runs on four D batteries or Mr. Heater's F276127 adapter, but Mr. Heater says it has removed the fan from some MH18B units, so check the listing if you want it. The manual asks for 18 square inches of fresh-air opening at both ceiling and floor level, says never to run it while sleeping or unattended, and warns it may shut off above 7,000 feet.
What we like
- Fan, where fitted, spreads heat across a room
- Three output levels for any space
- Same low-oxygen shutoff and tip-over switch as the small Buddy
Worth knowing
- Bigger, heavier, and too much heat for a tiny space
- Fan needs batteries or an adapter, and some units ship without one
Camco Olympian Wave-6 Catalytic Heater
Output: 3,200 to 6,000 BTUHeats: Up to 230 sq ftType: Flameless catalyticFresh air: 24 sq in, high and lowShutoff: Thermocouple only, no ODS listed
The Wave-6 is the pick when you want silent, even warmth you can mount on a wall. Catalytic heating is flameless and close to fully efficient, so it sips fuel and makes no fan noise at all. It needs a low-pressure propane supply: an RV's regulated line, or a portable cylinder through a low-pressure regulator and hose, and it mounts on a wall to save floor space. Camco's manual calls for a qualified LP gas technician for fixed installs and at least 24 square inches of fresh-air opening, ideally one high and one low. It lists a thermocouple that shuts off the gas if the pad goes out, but no oxygen depletion sensor or tip-over switch, so ventilation and a CO alarm matter even more here. It warms slower than a radiant Buddy and costs more, but for an RV, van, or cabin where quiet matters, it is hard to beat.
What we like
- Completely silent, no fan or electricity
- Very efficient, even radiant warmth
- Wall-mountable to free up floor space
Worth knowing
- Slower to warm a space than a radiant heater
- Needs a low-pressure regulator and hose, or a pro install on an RV line
- No oxygen sensor or tip-over switch listed
Compare the exact model, seller, and included accessories in the results.
Camco Olympian Wave-8 Catalytic Heater
Output: 4,200 to 8,000 BTUHeats: Up to 290 sq ftType: Flameless catalyticFresh air: 24 sq in, high and lowShutoff: Thermocouple only, no ODS listed
The Wave-8 is simply the bigger brother of the Wave-6, with more output for larger RVs and cabins while staying just as quiet. Same flameless catalytic tech, same wall-mount or portable setup, same 24 square inch fresh-air minimum and thermocouple-only shutoff in Camco's manual, more heat for a bigger box. If the Wave-6 would leave you cold in a fifth-wheel or a roomier cabin, this is the one to size up to. Run it on its lower setting most of the time and keep a high and a low opening clear, since more output means more oxygen used.
What we like
- More output while staying silent and efficient
- Portable or wall-mounted
- Great for larger RVs and cabins
Worth knowing
- Uses more oxygen at full output
- Same accessory needs as the Wave-6
- No oxygen sensor or tip-over switch listed
Compare the exact model, seller, and included accessories in the results.
Kidde Carbon Monoxide Alarm COB (AA Battery)
Power: 2 AA batteries (included)Sensor: Electrochemical, meets UL 2034Why: The mandatory companion
This is not optional gear, it is part of the heater. Any propane heater can produce carbon monoxide, and the oxygen sensor built into a Buddy does not detect CO. This Kidde COB alarm uses an electrochemical sensor and runs on two AA batteries, so it keeps working off-grid with no shore power. Kidde says to use alkaline AAs, not lithium. Mount it near where you sleep but not within 6 feet of the heater, the minimum Kidde's COB guide sets for heating appliances, and know that Kidde rates it for 40 to 100 degrees F, so a freezing tent is outside its range. Kidde designs it for heated or cooled living spaces, not RVs or boats, so for a van or RV, use a CO alarm rated for RVs instead. Everyone running a flame needs a CO alarm, and in a cabin or room this one covers it.
What we like
- Battery-powered, so it works fully off-grid
- Electrochemical sensor with a 10-year end-of-life alert
- Cheap insurance against carbon monoxide
Worth knowing
- Kidde says not for RVs or boats, and for conditioned spaces only
- Works from 40 to 100 degrees F only; replace it at 10 years
How to buy an indoor-safe propane heater
Start by confirming the heater is actually built for indoor use. The phrase you are looking for is an oxygen depletion sensor, often shortened to ODS, paired with a tip-over shutoff. The ODS cuts the gas if oxygen in the room runs low, and the tip-over switch kills it if the heater falls. Outdoor-only patio heaters skip both and have no business inside a tent or van. Both Mr. Heater Buddy models above have an ODS and a tip-over switch. The Camco Olympian Wave heaters list neither; they rely on a thermocouple that shuts off the gas if the catalytic pad goes out, so ventilation and a CO alarm carry even more of the load with them. Rules also vary by place: Mr. Heater restricts Buddy heaters from all indoor use in Massachusetts and Canada and from use in dwellings in California. If you shop elsewhere, do not assume, check the manual.
Next, size the BTU output to your space rather than buying the biggest unit you can. A 9,000 BTU Portable Buddy is plenty for a tent, truck cap, or small cabin room around 200 square feet. Step up to the Big Buddy's 18,000 BTU only when you are heating a real room, because an oversized heater in a tiny space just burns through fuel and oxygen faster while you crack the window wider to compensate. Matching output to the room is how you stay both warm and safe.
Then think about your fuel supply before you buy. The 1 pound disposable cylinders are convenient but expensive over a season, so plan to add a hose and filter that lets you run from a refillable 20 pound tank kept outdoors, since Mr. Heater's manual says never to bring a refillable cylinder indoors. That single accessory turns a pricey-to-run heater into a cheap one. Catalytic units like the Olympian Wave can also tap an RV's existing propane line, which is the tidiest setup of all if you have one.
Finally, decide between radiant and catalytic based on how you will use the heat. Radiant Buddy heaters warm fast and in a direction, ideal for quick heat you turn on and off. Catalytic Wave heaters are silent, run without electricity, and mount on a wall for steady background warmth, which suits an RV or cabin. Neither is set-and-forget overnight heat. Both want fresh air and a CO alarm, every single time.
Manufacturer manuals and safety guidance checked
We checked each safety feature and use limit above against these documents in September 2026, and the Kidde COB documents on October 9, 2026.
- Mr. Heater MH9BX Portable Buddy specifications and US owner's manual (2017 edition)
- Mr. Heater MH18B Big Buddy specifications and fan notice and US owner's manual (78438 Rev A, 2020)
- Mr. Heater Buddy series FAQ, including state and country restrictions
- Camco Olympian Wave 3, 6 and 8 installation and operating instructions (January 2009 edition)
- Kidde COB data sheet and user guide
- CPSC report on portable propane radiant heaters and oxygen depletion sensors
Frequently Asked Questions
Is it safe to run a propane heater indoors while sleeping?
No. Mr. Heater's manuals for both Buddy models say never operate the heater while sleeping and never leave it unattended, and the CPSC says not to use portable heaters while sleeping in tents, campers, or vehicles. Indoor-rated heaters with an oxygen sensor are built for supervised use in a vented space, so warm the space before bed, shut the heater off, and let a rated sleeping bag carry you through the night. Both radiant and catalytic propane heaters also add a lot of water vapor to the air, which causes condensation, and they consume oxygen as they burn. Treat them as supervised heat, not overnight heat.
What does the oxygen depletion sensor actually do?
The oxygen depletion sensor, or ODS, shuts the heater off if the oxygen in the room drops below roughly 18 percent, the level the CPSC describes for these heaters. It is a safeguard against suffocation and the incomplete combustion that follows when oxygen runs low. The key thing to understand is that it is not a carbon monoxide detector. It watches oxygen, not CO, so you still need a separate carbon monoxide alarm in the room. Both Mr. Heater Buddy models here have one, and Mr. Heater notes they may shut off above 7,000 feet, where there is less oxygen. Camco's Olympian Wave manual lists only a thermocouple that closes the gas valve if the catalytic pad goes out, so do not assume the Wave heaters have an ODS.
How much ventilation does a propane heater need?
Use the number in your heater's manual, not a rule of thumb. Mr. Heater's US manuals call for at least 9 square inches of fresh-air opening (about 3 by 3 inches) for the MH9BX Portable Buddy and 18 square inches (about 4.25 by 4.25 inches) at both ceiling and floor level for the MH18B Big Buddy. Camco's Olympian Wave manual asks for at least 24 square inches in total, ideally one opening high and one low, plus more if the space is tightly sealed or you run other fuel-burning appliances. Cracking a roof vent and a low window creates that high-and-low cross-flow without losing much heat.
How long does a 1 pound propane cylinder last?
Plan on about three hours on high and five to six hours on low for a 9,000 BTU Portable Buddy. That adds up quickly if you heat every night, which is why many people connect a 20 pound tank with a hose and filter instead. The bigger tank costs far less per hour and means fewer trips to refill. If you go that route, keep the tank outdoors, as Mr. Heater's manual requires, and never bring a refillable cylinder inside the living space.
Radiant or catalytic propane for a van or RV?
Radiant heaters like the Buddy series warm fast and in a direction, which is great for quick heat in a tent or truck cap. Catalytic heaters like the Olympian Wave run silent, need no electricity, mount on a wall, and give steady even warmth, which suits an RV with a built-in propane line. The Wave trades away the Buddy's low-oxygen shutoff and tip-over switch, though, since Camco's manual lists neither. Both need ventilation and a CO alarm. If quiet and a tidy install matter most, go catalytic. If instant heat, built-in shutoffs, and low cost matter most, go radiant.