Mr. Heater Buddy review
Mr. Heater Portable Buddy 4,000/9,000 BTU Radiant Propane Heater
By Tom Calder
Key specs
The maker's figures.
- Heat output (max)
- 9,000 BTU/hr
- Heats up to (maker)
- 225 sq ft
- Fuel
- Propane, one 1 lb cylinder
- Run time (maker)
- 5.4 h low, 2.4 h high on a 1 lb cylinder
- Safety shutoffs
- Low-oxygen shutoff
The heater most people mean by 'Mr. Heater Buddy': 4,000 or 9,000 BTU, for about 225 square feet, and approved by its maker for indoor and outdoor use, with a low-oxygen shutoff. On a 1 lb cylinder it runs 5.4 hours on low and 2.4 on high, so a long outage means a stack of cylinders. Like every fuel-burning heater it still makes carbon monoxide, so a battery-powered CO alarm in the room isn't optional.
- Best for
- The classic: one living room through an outage
- Skip it if
- You want hours from one cylinder
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Researched, not used. We haven't used this product. This review is built from the maker's specifications, owner reports and our own sizing.
What we like
- Approved by Mr. Heater for indoor use
- Low-oxygen shutoff
- Two heat settings
Worth knowing
- Only 2.4 hours on high per 1 lb cylinder
- The tip-over shutoff isn't listed on this listing
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Our review
The Mr. Heater Portable Buddy is a radiant propane heater that runs on 1-pound cylinders at 4,000 or 9,000 BTU, which the maker describes as indoor safe with an oxygen depletion sensor and tip-over shut-off. This review uses the maker's page and CDC's heating and carbon monoxide advice, and notes what we could not check.
What the maker says it is
Mr. Heater's page calls the Portable Buddy an indoor safe radiant propane heater that emits 4,000 or 9,000 BTU an hour and heats up to 225 square feet. It connects directly to a 1-pound propane cylinder, has Hi-Low heat settings, a swivel regulator, a fold-down handle and a piezo igniter. The model number is MH9BX and the warranty is 3 years limited.
The page recommends it for enclosed spaces such as large tents, and its list of uses also names emergency heat, garages, porches, workshops and job sites. Our indoor propane and kerosene heater comparison shows the larger models.
Run time: two figures
Mr. Heater gives two run times. The summary near the top says it provides 225 square feet of coverage for up to 5.4 hours. The specifications table lists 3 hours at maximum BTU and 6 hours at minimum BTU on a 1-pound propane cylinder.
Those figures do not match each other exactly, and the page does not explain the difference. Plan on the shorter one: at 9,000 BTU, each cylinder lasts around 3 hours, so a long outage calls for several cylinders. Store them as their labels direct.
Built-in safety systems
The page says the heater is equipped with safety shut-down systems, naming an oxygen depletion sensor (ODS) and an accidental tip-over safety shut-off. The spec table lists both as present. Mr. Heater also notes that the tip-over switch is now audible, so you can hear it operate if the unit is shaken, bounced or tipped upside down, and says this is normal.
The sensor is named for oxygen, and the page does not say it detects carbon monoxide. The page also lists a maximum elevation of 7,000 feet.
What CDC says about heaters and carbon monoxide
CDC's winter storm advice is to use combustion heaters only if they are properly vented to the outside, and it adds that some gas-fueled heaters, such as vent-less gas fireplaces, require some ventilation. It also says to use only the type of fuel your heater is designed to use, to keep heat sources at least 3 feet from drapes, furniture and bedding, and to install a battery-operated CO detector.
Mr. Heater's page describes this unit as indoor safe and does not mention a vent or flue, so it sits uneasily with CDC's wording. The practical answer is to follow the owner's manual to the letter, crack a window if the manual says to, and run a working battery-powered CO alarm in the room. CDC says to install battery-operated or battery back-up CO detectors near every sleeping area. See our carbon monoxide guide, space heater safety guide and CO alarm comparison. We could not read Mr. Heater's manual, so its ventilation and clearance rules are not covered here.
Fuel, accessories and restrictions
The page says the Buddy connects directly to a 20-pound cylinder with an optional hose and filter. It also warns in capitals that unauthorized accessories or attachments with this heater are expressly prohibited, may cause serious injury and void the warranty. Use only hoses, filters and accessories that Mr. Heater authorizes.
The page also lists a state restriction for Massachusetts, so check local rules before ordering. Check your local fire code too, particularly for apartments.
Who should skip it
Skip it if you cannot keep a battery CO alarm in the room, or if you want a heater to leave running overnight; the page does not address unattended use, so check the manual. If you want long run times, note that the page gives 3 to 6 hours on a 1-pound cylinder and no run time for the optional 20-pound hookup.
A researched review, built from the maker's specs, manual and US listings; facts checked 30 Oct 2026. Sources: Mr. Heater: Portable Buddy heater, MH9BX (maker's page); CDC: staying safe during and after a winter storm; CDC: carbon monoxide poisoning basics.
Who shouldn't buy this
Don't buy it if you want hours from one cylinder: the Big Buddy takes two and runs far longer on a 20 lb tank.
This is a Researched review: we haven't used this product. We check every specification against at least two independent sources, re-check the US price on a schedule where we can track it automatically, and say plainly who it isn't for. Commissions never change a rating.
If this isn’t the one
Best for A bit more heat than the Buddy, with tip-over protection listed
See the comparison →Best for A larger space, and the longest run on a 20 lb tank
See the comparison →Best for One small room, a bathroom or a home office
See the comparison →Questions
Is the Mr. Heater Buddy safe to use indoors?
Mr. Heater describes it as indoor safe, with an oxygen depletion sensor and tip-over shut-off. CDC's winter advice is to use combustion heaters only if they are properly vented to the outside, and says to install a battery-operated CO detector. Follow the owner's manual and keep a CO alarm in the room.
How long does a 1-pound cylinder last?
Mr. Heater's specifications list 3 hours at maximum output and 6 hours at minimum, while its summary says up to 5.4 hours. Plan on the lower number for high heat and keep several cylinders.
How big a room does it heat?
Mr. Heater says up to 225 square feet. The page does not say what ceiling height or outdoor temperature that figure assumes, so a poorly insulated room may feel less warm.
Can it run on a large propane tank?
Mr. Heater says it connects directly to a 20-pound cylinder with an optional hose and filter. It warns that unauthorized accessories are prohibited and void the warranty, so use only accessories Mr. Heater authorizes.