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Propane tank top heater: outdoor radiant heat on a 20 lb tank

By the Plain Prepper editors. Updated 2026-10-15.

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Quick answer

A tank top heater screws onto a propane cylinder and throws radiant heat from one, two or three burners. Mr. Heater's single MH15T runs 10,000 to 15,000 BTU per hour and lists a 375 square foot heating area; the double MH30T runs up to 30,000 BTU for 750 square feet. Mr. Heater lists these heaters as outdoor use only and not indoor-safe, for job sites, loading docks, sporting events, hunting and camping. Never use one inside a home, garage or tent.

Single, double and triple compared

Spec	MH15T single	MH30T double	MH45T triple
Output	10,000 to 15,000 BTU/h	10,000 to 30,000 BTU/h	10,000 to 45,000 BTU/h
Heating area	375 sq ft	750 sq ft	1,125 sq ft
Burners	1	1 or 2, swivel heads	1, 2 or 3, adjustable heads
Tip-over shut-offs	1	2	3
Tank	5 to 20 lb cylinder	20 lb	20 lb
Ignition	Match lit	Match lit	Match lit
Indoor-safe	No	No	No

Mr. Heater's heating areas work out to 25 square feet per 1,000 BTU across all three. It also sells spark-ignition versions of the single and double, and we did not find the MH45T on Amazon in October 2026.

Why outdoor only

• Maker's limit: Mr. Heater lists each tank top heater as outdoor use only and marks indoor-safe as No.
• Carbon monoxide: CPSC calls CO the invisible killer, a colorless, odorless gas, and says more than 200 people in the United States die each year from accidental non-fire CO poisoning tied to consumer products.
• Open flame and fuel: the burner sits directly on a full propane cylinder; keep it away from anything that can burn.
• For indoor heat, use a heater the maker rates for indoor use, such as those in our indoor propane heater and Mr. Heater Buddy guides, with a working CO alarm.

Setting one up

1. Stand the tank upright on firm, level ground outdoors, away from tents, tarps, hay and gas cans.
2. Attach by hand: Mr. Heater lists a soft-nose P.O.L. connection with a hand wheel, so no tools are needed.
3. Check the connection using the leak-check steps in the heater's manual before lighting.
4. Light it as the manual directs; these models are match lit.
5. Set the heat with the high-medium-low regulator on the single, or by burner and setting on the double and triple.
6. Aim the heads at people or work, not at the tank or nearby materials.

Picking the size

• One or two people: the single MH15T's 375 square feet suits a sideline bench or an open outdoor work spot.
• Small crew or tailgate: the double MH30T covers 750 square feet and lets you run one or both burners.
• Larger areas: the triple covers 1,125 square feet; Mr. Heater lists eight heat settings from 10,000 to 45,000 BTU.
• Aim: radiant heat warms what it faces, so point the reflector or heads toward people, not toward the tank.

What the BTU settings mean for your propane

• BTU per hour is the burn rate: the number on the knob or label is how much fuel energy the heater uses each hour, so a higher setting empties the tank faster.
• Same low for all three: each Mr. Heater tank top starts at 10,000 BTU per hour, so on low the double and triple use propane no faster than the single.
• Turning it up: the double at its 30,000 BTU top setting burns fuel three times as fast as it does at 10,000; the triple at 45,000 burns four and a half times as fast.
• Practical habit: run the lowest setting that keeps people comfortable, and bring a spare filled cylinder for a long day outdoors.

For cylinder sizes and refills, see our propane tank guides.

Safety habits for any propane heater

• CO alarms at home: CPSC recommends battery-operated or battery-backup CO alarms on every level and outside sleeping areas, and says interconnected alarms are best.
• Know the symptoms: headache, dizziness, weakness, nausea, vomiting, sleepiness and confusion; get to fresh air and call 911, CPSC says.
• Tip-over shut-off: each burner has one; never defeat it.
• Storage: store cylinders outdoors, upright, with the valve closed; see our 20 lb propane tank guide.

What to look for when you buy

Questions people ask

Can you use a propane tank top heater indoors?

No; Mr. Heater lists its tank top heaters as outdoor use only and not indoor-safe.

How big an area does a tank top heater heat?

Mr. Heater lists 375 sq ft for the single, 750 for the double and 1,125 for the triple.

What size propane tank does a tank top heater use?

The single fits 5 to 20 lb cylinders; the double and triple list a 20 lb tank.

How does a propane tank top heater work?

It mounts on the cylinder valve and burns propane on a radiant surface, aimed by a reflector or swivel head.

Sources

• MH15T Single Tank Top Heater, Mr. Heater
• MH30T Double Tank Top Heater, Mr. Heater
• MH45T Triple Tank Top Heater, Mr. Heater
• Carbon Monoxide Information Center, U.S. Consumer Product Safety Commission

Sources checked 2026-10-15.