Mr. Heater Big Buddy Review: Heats Up to 400 sq ft With Direct Cylinder Connections

The Big Buddy in Short

Mr. Heater Big Buddy Propane Heater heats 18,000 BTU/hr for you if you need room heat from a 1-lb propane setup.

If your backup heat needs to fit a 400 sq ft room, a heater that runs from 1-lb cylinders is a very different buy from a garage unit.

Mr. Heater Big Buddy matches that situation with 18,000 BTU/hr and a direct connection to two 1-lb disposable cylinders. The optional hose also lets it connect to a 20-lb cylinder, so the fuel format is not fixed to one setup.

We screened 31 Propane Heaters and this is one of 15 chosen for a full review. Full reviews go to the most-rated products that pass screening, at most 2 per brand. Big Buddy has 273 buyer ratings, the 7th most of the 31 screened. This review is for you if you already own an older propane heater and want a portable replacement with the same kind of fuel flexibility.

If you require more industrial power, see our analysis of the DXH70CSFAVX for high-BTU heating needs.

The Short Answer on the Big Buddy

Best for: you need a propane heater that can warm one room during a few hours without moving to a larger output class.

Big Buddy is the right pick if you want 18,000 BTU/hr and a 400 sq ft coverage claim for around $199.28.

• Pro: 18,000 BTU/hr gives you enough output for one-room heating during a short outage.
• Pro: The 400 sq ft coverage figure suits a single room or similarly sized space.
• Pro: It states automatic low-oxygen shutoff and an accidental tip-over safety shutoff.
• Con: 18,000 BTU/hr is not enough for a larger garage, so you should not expect it to cover that job alone.
• Con: The 1-lb cylinder format limits runtime and pushes refill logistics onto you if you need longer use.

Don’t buy this if: you need one heater for a larger garage or open area that calls for around 25,000 BTU/hr or more.

Price assessment: Around $199.28 is fair for this output, coverage claim, and safety feature set.

Key Specifications for Heat Output, Fuel, and Coverage

Heat output separates the Big Buddy most. It measures how much heat the heater can release each hour.

Before You Buy: Propane Heater Checklist

The first thing to check is whether your space can use an 18,000 BTU/hr propane heater and whether you already have a 1-lb cylinder setup or need the optional hose for a 20-lb cylinder.

• ☐ Confirm your room size is about 400 sq ft or smaller — if your space is larger, you will need a different heater or you will live with an underpowered result.
• ☐ Check that your fuel plan matches the built-in setup — it connects directly to two 1-lb disposable cylinders, and a mismatch means you must buy a hose and 20-lb cylinder before normal use.
• ☐ Measure where you will place the heater and compare it with the wall-mount format — the listing states wall mounting, so a different setup can leave you reworking the space or choosing another model.
• ☐ Confirm you want an automatic low-oxygen shutoff system — if you skip this check, you may end up with a heater that does not match your safety preference for indoor use.
• ☐ Confirm you want an accidental tip-over safety shutoff — without that feature, you would need a different model if that protection matters to your room setup.
• ☐ Budget for cylinders because they are not included — if you overlook that, the heater arrives without fuel and you will still need to buy propane before you can use it.

If you need more than 18,000 BTU/hr for a larger garage or open workshop, do not buy this one.

What the Numbers Mean in Use

What Heat Output Levels Mean for Single-Room Use

You can use Big Buddy for a room up to 400 sq ft when your goal is single-room heat, not whole-house coverage. Its 18,000 BTU/hr rating sits in the range that can handle one room during an outage, and the 4,000 and 9,000 BTU settings give you lower output for tighter spaces or lighter demand.

That range matters because 18,000 BTU/hr is still short of the output usually associated with larger garages or open areas, so this heater suits a room-first job better than a big open space. If you are trying to warm a tent or a small room without pushing heat too hard, the lower settings help, while the full output is the one to use when you need the room-heating end of the range.

Why Safety Shutoff Systems Matter for Indoor Propane Heat

Big Buddy states an automatic low-oxygen shutoff system and an accidental tip-over safety shutoff, which are the safety features that matter most for indoor propane heat. For you, that means the heater is built with two shutdown protections tied to the common indoor risks of oxygen depletion and tipping.

Those features do not change the heater’s output, but they do shape where you should plan to use it and what conditions you need to keep in mind. A unit with both protections is more relevant for enclosed spaces than a heater that states neither, yet you still need to treat carbon monoxide and moisture as real indoor propane concerns.

How Cylinder Connection Options Change Runtime Planning

Big Buddy connects directly to two 1-lb disposable cylinders, and it can also connect to a 20-lb cylinder with an optional hose. That gives you a portable setup for short use and a larger-cylinder setup for longer runtime planning.

The cylinder choice changes how you think about the heater’s 18,000 BTU/hr output. Two 1-lb cylinders suit a lighter, more portable setup, while a 20-lb cylinder makes more sense if you want fewer refills and a steadier fuel supply for a longer room-heating job.

Which Jobs the Big Buddy Handles, Worked Out From Its Specs

The Big Buddy against the jobs buyers ask about, worked out from its listed heat output and a typical need for each job.

How the Big Buddy Compares to Alternatives

Big Buddy’s clearest advantage is output for the money: it states 18,000 BTU/hr and costs around $199.28. That gives you more heat than the 10,000 BTU/HR Mr. Heater Vent Free Radiant Propane Heater, while staying below the price of the $214.99 model.

• Against the Avenger FBDTP30, Big Buddy gives you 18,000 BTU/hr instead of 30,000 maximum BTU. If you need the stronger output for a larger space, Avenger is the better pick.
• Against the BILT HARD 85000 BTU Heater, Big Buddy uses a 1-lb fuel tank size, while BILT HARD uses a 20 lb tank. You should choose BILT HARD if longer runtime from a larger cylinder matters more than portability.
• Against the InoKraft Maxheat MH125, Big Buddy is the lighter fuel option at 1-lb versus 20 lb. That makes Big Buddy the easier match if you want disposable-cylinder convenience instead of bulk fuel capacity.
• Against the CAMMOO Propane Heater, Big Buddy states 400 sq ft of coverage, while CAMMOO gives no coverage figure here. If room size needs to be stated in the listing, Big Buddy is the clearer choice.
• Against the Mr. Heater Vent Free Radiant Propane Heater, Big Buddy ranks higher on heat output, with 18,000 BTU/hr versus 10,000 BTU/HR. The smaller unit makes more sense if you are only heating a tighter room and want the lower-output class.

If you want the highest-output option in this group, pick the Avenger FBDTP30 instead. Its 30,000 maximum BTU is the stronger match for a larger room than Big Buddy’s 18,000 BTU/hr.

You can also view our full review of the Maxheat MH125 to see how its specifications compare.

For a different power output, examine our spec breakdown of the MaXheat MH68.

Getting the Big Buddy Working, and What to Check After

Getting This Propane Heater ready to run

A 1-lb propane cylinder is the one thing Big Buddy needs before it can do anything useful.

1. Unpack the heater and confirm that the box includes the heater itself, because cylinders are not included.
2. Attach two 1-lb disposable cylinders, or prepare a 20-lb cylinder with an optional hose if you want the larger fuel format.
3. Set the heater where its 400 sq ft coverage matches the room you want to warm.
4. Choose the fuel connection that matches your cylinder size, since the heater connects directly to two 1-lb cylinders or to a 20-lb cylinder with the optional hose.
5. Start the heater at one of its stated output levels: 4,000 BTU/hr, 9,000 BTU/hr, or 18,000 BTU/hr.

Warranty and support: what to verify for this propane heater

Warranty cover differs by seller and country.

• Confirm the return window before it closes, because the heater depends on a propane cylinder and the box does not include one.
• Confirm whether the sale includes the optional hose, since the 20-lb cylinder setup needs that extra part.
• Confirm that the heater’s low-oxygen shutoff and tip-over shutoff are listed in your order details, because those are the safety features named for this model.
• Confirm the support contact route for replacement parts, because the heater uses propane and those parts affect operation.

On the day it arrives, open the box and verify the included parts against your order while the return window is still open.

What Buyers Still Want to Know About This Propane Heater

How long does the Big Buddy run on one 1-lb cylinder at each heat setting?

Big Buddy runtime on a 1-lb cylinder is not stated for the 4,000 BTU/hr, 9,000 BTU/hr, or 18,000 BTU/hr settings. The listing does say it connects directly to two 1-lb disposable cylinders, so the runtime question depends on the setting you plan to use and the cylinder size you choose. One cylinder. Two cylinders.

How much propane does the Big Buddy burn, and is it expensive to run for a whole evening?

Big Buddy propane burn rate is not stated, so the evening cost cannot be calculated from the listing alone. The stated heat output is 18,000 BTU/hr, and that tells you the heater is sized for room heating rather than light supplemental warmth. The price is around $199.28, but operating cost still depends on the fuel rate, which is not given.

Does the Big Buddy work for one room during a power outage?

Yes, the Big Buddy is listed for 400 sq ft, and that is the kind of coverage that suits one room during a few hours without power. Its 18,000 BTU/hr output is enough for that job in the data provided. If your room is larger, the coverage figure matters more than the heater’s name.

Can the Big Buddy heat a larger garage without a second heater?

No, the Big Buddy is not sized for a larger garage without help. Its 18,000 BTU/hr output sits in the range for a single room, not the 25,000 to 35,000 BTU/h range that job usually needs. The 400 sq ft coverage figure also points to a smaller space.

Does the Big Buddy use propane cylinders or a fixed connection?

Big Buddy uses propane cylinders, and the listing says it connects directly to two 1-lb disposable cylinders. It also connects to a 20-lb cylinder with an optional hose, so you can choose between portable and longer-run fuel formats. Cylinders are not included.

What safety shutoffs does the Big Buddy list?

Big Buddy lists an automatic low-oxygen shutoff system and an accidental tip-over safety shutoff. Those are the two safety features named in the data, and they matter because indoor propane heaters face oxygen depletion and tip-over risks. The listing does not add any other shutdown detail.

Is the Big Buddy Right for You?

Who the Big Buddy suits and the jobs it is the wrong choice for, listed below with the reason for each.

Where to Buy This Propane Heater

Propane heaters are sold by the retailers below – we do not track which of them has the Big Buddy in stock, so check availability and the current price with the retailer before making a trip.

• Northern Tool + Equipment (online and physical stores) — breadth of range for jobsite and utility heaters
• Ace Hardware (online and physical stores) — local-store convenience and in-store returns
• Walmart (online and physical stores) — broad mass-market selection and easy pickup options
• Amazon (online only) — breadth of range across many brands and models
• Home Depot (online and physical stores) — broad range of propane heaters and in-store returns
• Lowe’s (online and physical stores) — broad range of propane heaters and in-store returns
• Tractor Supply Co. (online and physical stores) — useful for rural-oriented heating gear and specialist staff

Final Verdict on the Big Buddy

You should choose the Big Buddy if you need a propane heater for a room-sized outage load, not a larger garage or open workshop. At around $199.28, it gives you 18,000 BTU/hr and a 400 sq ft coverage rating.

The strongest number here is the 18,000 BTU/hr output. That is enough for one room when the power is out for a few hours, and it is the figure that keeps this model in the portable-heater range rather than the larger-space class.

Skip it if: you need one heater for a larger garage, or you want a unit sized for big barn and open-workshop heating.