The Big Buddy delivers 18,000 BTUs at maximum output with two lower settings at 9,000 and 4,000 BTUs, heating up to 450 square feet. That’s enough firepower to warm a construction trailer, temporary job site shelter, or decent-sized workshop when Montana temperatures plunge below freezing.
This three-setting propane heater runs up to 11 hours on low with dual 1lb tanks, covering a full work day without swapping cylinders. The unit features both dual 1lb cylinder connections and the ability to connect to 20lb tanks with optional hoses, plus a Quick Connect LP port for regulated low-pressure propane sources like RV connections.
At 7,000 feet maximum elevation, this heater works throughout most of Montana’s populated areas. The low oxygen sensor prohibits use at altitudes of 7,000 feet or above — that’s a hard limit for mountain job sites, but covers the Flathead Valley, Missoula, and most construction zones.
Heat Output and Fuel Consumption Specs
| Specification | Value |
|---|---|
| BTU Output Settings | 4,000 / 9,000 / 18,000 BTU/hr |
| Heating Area | Up to 450 sq ft |
| Run Time (Low Setting) | Up to 11 hours with dual 1lb tanks |
| Fuel Consumption (Max BTU) | 0.834 gallons/hour |
| Weight | 17.1 lbs |
| Dimensions | 19” (L) x 12” (W) x 17.5” (H) |
At 0.834 gallons per hour fuel consumption on high, a 20lb tank delivers roughly 5.5 hours of maximum heat. Drop it to the 9,000 BTU medium setting and runtime doubles. The math matters when planning remote job site heating where propane runs aren’t convenient.
The heater runs up to 108 hours on a single 20lb propane tank — that’s on the lowest setting, but shows the efficiency potential when you need extended runtime over raw heat output.
Safety Features for Indoor Construction Use
The Big Buddy includes an Oxygen Depletion Sensor (ODS) for indoor safety and an accidental tip-over safety shut-off system. It’s CSA Certified and ANSI Standard compliant, certified for indoor safe use with proper ventilation/clearance as specified in the manual.
It has been designed and approved for indoor use. That certification matters for construction trailers, enclosed job sites, and workshops where carbon monoxide becomes deadly fast. The ODS shuts down the unit before oxygen levels drop to dangerous levels — not foolproof, but a critical backup when workers get focused on the job instead of ventilation.
Dual ceramic burner tiles with shock-absorbing insulation handle the thermal stress of constant heating cycles. A heavy-duty safety wire guard protects those tiles from job site impacts. These aren’t decorative features — they’re what keeps the heater running after getting knocked around in the back of a truck all winter.
Note: Fan feature has been removed from newer models (MH18B) due to import tariffs. Features include built-in protection probe, easy carry handle, accidental tip-over safety shut-off, automatic low oxygen shut off system, blower fan, power On/Off switch, large 4 position heat level control knob with built-in piezo starter — though that blower fan description applies to older units, not current production.
The Big Buddy earns its place on Montana job sites through practical design choices. Swivel-out regulators for easy tank installation mean frozen fingers can still swap propane cylinders. The fold-down handle for portability tucks away when space gets tight in a construction trailer.
Reviews average 4.2 to 4.5 stars based on 300+ reviews on major retail sites. Pros include excellent heat output for large spaces, reliable safety features (ODS and tip-over), versatile fuel options (1lb or 20lb tanks), and easy to start and adjust. Cons: regulators can be sensitive or prone to failure if high pressure is applied without a filter, fan is missing from newer units, and high propane consumption on maximum setting.
Compatible with F273704 (10ft hose) or F273699 (fuel filter + hose) for large tank connections. That fuel filter matters — use of unauthorized accessories/attachments (like non-filtered hoses on some connections) may void the warranty.
The unit comes with a 1 Year Limited Manufacturer Warranty covering defects in materials and workmanship.
Frequently Asked Questions
Q: How long will the Big Buddy run on a 20lb propane tank?
The heater runs up to 108 hours on a single 20lb propane tank on the lowest 4,000 BTU setting. At maximum 18,000 BTU output with 0.834 gallons/hour consumption, expect roughly 5.5 hours from a 20lb tank.
Q: Can I use this heater above 7,000 feet elevation?
No. Maximum elevation is 7,000 feet, and the low oxygen sensor prohibits use at altitudes of 7,000 feet or above. The ODS will shut the unit down at higher elevations.
Q: What’s included with the heater?
The standard package includes the heater unit and owner’s manual. Optional accessories include F273699 Fuel Filter, F273704 10ft Buddy Series Propane Hose, F272702 12ft Big Buddy Hose with Regulator, and a carry bag (sold separately).
Q: Does the new Big Buddy still have a fan?
Fan feature has been removed from newer models (MH18B) due to import tariffs. Older units had fans, current production does not.
Q: Is it really safe for indoor use?
The Big Buddy is CSA Certified, ANSI Standard compliant, and certified for indoor safe use with proper ventilation/clearance as specified in the manual. It has been designed and approved for indoor use. The Oxygen Depletion Sensor (ODS) provides an additional safety layer by shutting down the unit if oxygen levels drop.
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