The best Mr. Heater for most people comparing the Buddy line is the Portable Buddy MH9BX: it offers three heat settings, is rated by the manufacturer for spaces up to 225 square feet, and can run from a one-pound propane cylinder. Choose the Big Buddy MH18B when its higher output is appropriate for your space and local rules allow that exact version. The right choice depends on the model’s output, fuel setup, regional use eligibility, and the instructions for your specific unit—not BTU rating alone.
Which Mr. Heater Buddy heater should I buy?
Use the manufacturer’s output and coverage figures as a first filter, not a guarantee of even or comfortable heat. Actual results depend on the enclosure and conditions, and each figure below is a manufacturer-stated rating. The comparison chart appears in Mr. Heater’s 2023 product catalog; confirm current specifications on the individual product page before buying.
| Model | Manufacturer-stated output | Manufacturer-stated area | What to consider |
|---|---|---|---|
| Little Buddy MH4B | 3,800 BTU | Up to 95 sq. ft. | A compact option for a smaller area. |
| Portable Buddy MH9BX | 4,000, 6,000, or 9,000 BTU | Up to 225 sq. ft. | Three settings and direct connection to a one-pound cylinder; remote-cylinder use requires a compatible optional hose and filter. |
| Hunting Buddy MH12HB | 12,000 BTU | Up to 300 sq. ft. | A fixed-output, mid-range option in the manufacturer’s comparison. |
| Big Buddy MH18B | 4,000, 9,000, or 18,000 BTU | Up to 450 sq. ft. | Higher output and two one-pound cylinder connections; some versions have had the fan removed, so check the exact listing. |
These specifications are from Mr. Heater’s comparison catalog. The MH9BX product page also lists its 4,000- and 9,000-BTU settings and coverage up to 225 square feet. Verify the current product details for the specific unit you are considering.
Choose the MH9BX for adjustable output and a simple cylinder setup
The MH9BX is the clearest all-purpose pick among these models when its regional version is allowed for your intended use. Its three listed settings let you select between 4,000, 6,000, and 9,000 BTU. It accepts a one-pound cylinder directly; connecting to a remote propane supply calls for the manufacturer-approved hose and filter described on the product page. Do not assume a generic hose or attachment is suitable.
#1 Best Overall
- Emits 4,000 or 9,000 BTU/hr radiant heat
- Designed and approved for indoor and outdoor use
- Heats up to approximately 225 square feet
- Features emergency low oxygen safety system
- 2 temperature settings: low and high
Choose the MH18B when its higher output fits the job
The MH18B reaches a manufacturer-listed 18,000 BTU and is rated for up to 450 square feet. Its product information describes connections for two one-pound cylinders and an optional hose for a 20-pound cylinder. Check the exact listing: the manufacturer notes that some MH18B versions have had the fan removed. Output, fan configuration, fuel supply, and local eligibility all matter to the choice.
Consider the smaller or fixed-output models for a narrower need
The MH4B’s 3,800 BTU rating and up-to-95-square-foot coverage make it the smallest option in this comparison. The MH12HB has a listed output of 12,000 BTU and coverage up to 300 square feet. The catalog provides no multi-setting output for either model in this comparison, so check each current product listing and manual for the version’s controls and fuel setup.
How big of a Mr. Heater do I need?
Start with the area rating as a screening tool, then consider how the space is enclosed, the conditions in which it will be used, the available fuel supply, and the model’s permitted use in your location. A manufacturer coverage figure does not establish that a heater will provide equivalent comfort in every enclosure. Do not choose a larger model solely because its maximum BTU number is higher; choose an output range and configuration suited to the intended space and permitted use.
Rank #2
- Heats up to 450 square feet
- Low, Medium, and High heat settings: 4,000 / 9,000 / 18,000 BTU
- Heats up to 216 hrs. on two 20lb Propane tanks with optional hose (low setting)
- Big Buddy dual heating system combines radiant heat comfort with convection heat air flow
- Built-in high powered fan
- For a small area, compare the MH4B’s rating of up to 95 square feet with the MH9BX’s rating of up to 225 square feet.
- For a mid-sized area, the MH12HB is rated up to 300 square feet; the MH9BX also covers an area within that range and offers three output settings.
- For an area approaching the MH18B’s stated maximum of 450 square feet, confirm that the exact model and regional version are permitted for the setting and that its fuel connection meets your needs.
These are manufacturer-stated coverage figures, not independent performance measurements. Consult the model’s manual for operating limits and installation clearances rather than treating the area rating as a substitute for those instructions.
Can I use a Mr. Heater Buddy indoors?
There is no single answer for every Buddy heater: indoor-use eligibility differs by model version and jurisdiction. Check the label on the unit, the manual supplied with that exact regional model, and local requirements before use. Do not assume that instructions or marketing for one version apply to another.
MH9BX: check the regional version and manual
The U.S. MH9BX owner manual describes an unvented gas-fired heater that uses air from the area and requires adequate combustion and ventilation air. It lists model-specific clearances of 30 inches above, 24 inches at the front, 6 inches at the sides, and 0 inches at the rear; verify those figures against the manual supplied with your heater.
Rank #3
- 🔥【ATTENTION】Fuel is Not Included. Please keep this duel fuel portable heater away from flammables. Always check gas leakage before operation. For your safety, please store the heater after the TANK is REMOVED, and DISCONNECT it from the cylinder if you don't plan on using it.(PROPANE TANKS ARE NOT INCLUDED)
- 🔥【Dual Fuel Butane/Propane Heater】Our dual fuel outdoor heater works efficiently with both 8 oz. butane canisters and propane tanks. It comes with an 8FT propane hose for connecting to 1 lb propane cylinders, and is also compatible with 20 lb propane tanks for extended outdoor heating.
- 🔥【Camping Heater: Safe to Use】The camping heater features butane cartridge ejection and a safety lock, as well as tip-over and low-oxygen safety auto shutoff for secure operation during use. These safety features ensure safe operation and prevent accidents.
- 🔥【Powerful Tent Heater】Our powerful propane tent heater generates an impressive 9000 BTU using cutting-edge heating technology. It swiftly and effectively heats an area of 200 square feet, ensuring your comfort and coziness during chilly weather.
- 🔥【Lightweight Portable Heater 】This compact and lightweight propane heater is designed for easy portability and quick setup, making this portable camping heaters for tents the perfect companion for outdoor activities such as camping, hiking,fishing,hunting, skiing and more.
Mr. Heater identifies a separate Canada/Massachusetts MH9BX version as outdoor use only. Its Buddy Family FAQ says that Canadian and Massachusetts law prohibit indoor use of unvented heaters. The outdoor-only designation is specific to that regional version; it should not be applied to every MH9BX or overridden by instructions for a different SKU.
Big Buddy: heed the Canada/Massachusetts manual’s restriction
The Canada/Massachusetts Big Buddy MH18B manual warns that the appliance can produce carbon monoxide and says: “Never use this appliance in an enclosed space such as a camper, tent, car or home.” Apply the instructions for the exact model and region rather than transferring another version’s guidance.
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Safety features do not replace operating instructions
An oxygen depletion sensor (ODS) or tip-over feature does not make a model suitable for a use prohibited by its label, manual, or local rules. The MH9BX manual also states: “NEVER LEAVE THE HEATER UNATTENDED WHILE BURNING!” Follow all model-specific ventilation and clearance instructions.
Rank #4
- 3,800 BTU per hour
- For use with propane gas
- Heats up to 95 sq ft
- One button ignition on function
- 8in round stand; uses little floor space
What fuel setup and accessories should I plan for?
The MH9BX connects directly to a one-pound propane cylinder. For a remote cylinder, Mr. Heater describes an optional hose and filter on the product page. The Big Buddy page describes connections to two one-pound cylinders and an optional hose for a 20-pound cylinder. Confirm compatibility for the exact model and accessory before connecting anything.
Mr. Heater warns against unauthorized attachments, which may cause serious injury and void the warranty. Its warranty policy excludes coverage for use inconsistent with the owner’s manual and for handmade or third-party accessories or attachments. Use only accessories the manufacturer identifies as compatible with your unit.
What should I check before buying or operating one?
- Match the full model number and regional version to the product listing and manual.
- Confirm that the intended location is allowed by that version’s instructions and local requirements.
- Compare the manufacturer’s output settings and area rating with your space, without treating coverage as a comfort guarantee.
- Check the fuel-cylinder arrangement and whether the setup requires an approved remote-cylinder hose and filter.
- For an MH18B, verify whether the exact version includes a fan.
- Follow the supplied manual’s ventilation, clearance, and supervision requirements; never leave the MH9BX burning unattended.
Can an MH9BX pilot assembly be replaced?
Mr. Heater lists replacement part F273401, a pilot assembly with ODS, for MH9B models from 2001–2008 and MH9BX models from 2009 onward. Check the heater’s model and serial information and follow manufacturer service guidance before ordering or attempting a repair. See the F273401 listing for stated compatibility.
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