Mr. Heater Big Buddy PRO Series 18,000 BTU Heater Review: The Ultimate Portable Powerhouse for Beating the Cold

There’s a unique kind of cold that seeps into your bones and brings all productivity to a halt. For me, it was in my detached garage workshop during a particularly brutal Pacific Northwest cold snap. The air was frigid, my tools felt like blocks of ice, and my fingers were too numb to safely operate anything. I was trying to finish a project on a deadline, but the cold was an insurmountable wall. Standard electric space heaters barely made a dent in the large, uninsulated space. I needed something powerful, reliable, and, most importantly, safe enough to use for hours on end without constant worry. This quest for a dependable heat source is a familiar story for anyone who works in a garage, enjoys winter camping, needs emergency home heating during a power outage, or simply wants to enjoy their patio on a crisp evening. Without an effective solution, these spaces become unusable, and emergency situations become truly dangerous.

What to Consider Before Buying a Portable Propane Heater

A portable propane heater is more than just an item; it’s a key solution for reclaiming your spaces from the cold and ensuring comfort and safety when you need it most. Unlike electric heaters that tether you to an outlet, or built-in systems that are costly and immobile, a portable propane heater offers unparalleled freedom and potent heating capacity. They generate significant BTUs (British Thermal Units), allowing them to heat larger areas much more quickly and efficiently than their electric counterparts. This makes them ideal for garages, workshops, construction sites, patios, and even for providing life-saving warmth during power failures. Their self-contained design means you have a robust source of heat anywhere you can carry the unit and a propane tank.

The ideal customer for this type of product is someone facing inconsistent or inadequate heating in spaces up to around 450 square feet. This includes hobbyists in their garages, families who enjoy RVing or camping in colder seasons, homeowners looking for a reliable emergency backup, and outdoor enthusiasts who need warmth in a hunting blind or ice fishing shack. However, it might not be suitable for those who need to heat a very small, poorly ventilated indoor space or for someone who is uncomfortable handling propane canisters. For those seeking a permanent, fixed heating solution for a patio with easy access to electricity, a wall-mounted electric infrared heater might be a better, more convenient long-term alternative.

Before investing, consider these crucial points in detail:

• Heat Output & Coverage (BTUs): The heating power of these units is measured in BTUs. A higher BTU rating means more heat and the ability to warm a larger area. The Mr. Heater Big Buddy PRO Series 18,000 BTU Heater offers adjustable settings (4,000, 9,000, and 18,000 BTUs), which provides critical versatility. You can use the low setting for a small tent or to maintain temperature, and the high setting to rapidly heat a large, cold garage. Always match the heater’s maximum coverage area (e.g., 450 sq ft) to your space.
• Safety Features: When dealing with combustion indoors, safety is paramount. Look for a multi-tiered safety system. Essential features include a Low-Oxygen Safety Shutoff (ODS), which automatically turns the unit off if oxygen levels in the room drop too low, and a tip-over switch that immediately cuts the gas supply if the heater is knocked over. These are non-negotiable for any indoor use.
• Fuel Source & Portability: Most portable heaters run on 1 lb disposable propane canisters or can be adapted to use larger 20 lb refillable tanks. The ability to use both offers the best of both worlds: extreme portability with the small tanks and long-term, cost-effective operation with the larger one. Consider the unit’s weight, dimensions, and whether it has a sturdy carrying handle for easy transport.
• Ignition & Ease of Use: Look for a simple and reliable ignition system. A push-button Piezo igniter is common and works without batteries. The controls should be intuitive and easy to operate, even with gloves on. A heater with a complicated startup procedure can be a source of frustration, especially in freezing conditions. Some models, as we discovered, may have a battery-assisted ignition, which is a key detail to verify.

Understanding these factors will ensure you choose a heater that not only performs well but does so safely and conveniently for your specific needs.

While the Mr. Heater Big Buddy PRO Series 18,000 BTU Heater is an excellent choice for portable heating, it’s always wise to see how it stacks up against the competition, especially if you’re considering a permanent installation. For a broader look at all the top models designed for fixed locations, we highly recommend checking out our complete, in-depth guide:

First Impressions: Built Like a Trusty Tool

Unboxing the Mr. Heater Big Buddy PRO Series 18,000 BTU Heater, the first thing we noticed was its purposeful, utilitarian design. It feels less like a fragile appliance and more like a durable piece of equipment you’d find in a well-stocked workshop. The combination of sturdy plastic and metal gives it a reassuring heft of just over 14 pounds, and the large, integrated handle makes it easy to carry. There’s no assembly required; it’s ready to go straight out of the box. The signature red color is iconic for the brand and makes it highly visible. The front is dominated by the two large ceramic heating tiles, protected by a wire guard. On either side, doors open to reveal the swivel-out regulators for connecting two 1 lb propane cylinders. The large control knob on top is simple and intuitive, with clear markings for “Off,” “Pilot,” and the three heat levels. It feels robust and built to withstand the bumps and bruises of being transported to a campsite, job site, or just around the garage. It’s a design that prioritizes function and durability over aesthetics, which is exactly what we want from a product like this. You can see the full specs and user photos online.

Performance Deep Dive: Putting the Big Buddy to the Test

A heater’s spec sheet only tells part of the story. To truly understand its capabilities, you have to put it through its paces in the real world. We tested the Mr. Heater Big Buddy PRO Series 18,000 BTU Heater in a variety of scenarios, from a cold 400 sq ft garage to a chilly outdoor patio, focusing on its core functions: raw heating power, critical safety systems, and overall usability.

Heating Power & Performance: A Radiant Giant

The primary job of any space heater is to produce heat, and in this regard, the Big Buddy is an absolute champion. Firing it up to the high setting of 18,000 BTUs is an impressive experience. The two large ceramic panels begin to glow a satisfying, bright orange within a minute, and you can immediately feel the powerful wave of radiant heat pouring out from the unit. In our 400 sq ft garage test, with an ambient temperature of 40°F, the heater raised the temperature in the immediate 10-foot vicinity to a comfortable 65°F in about 45 minutes, with the overall garage temperature climbing to the mid-50s in just over an hour. This is a remarkable performance for a portable unit. This experience is echoed by numerous users, one of whom noted they could heat their 20’x24′ insulated garage from 40 degrees to nearly 65 degrees and maintain it on a lower setting. Another user reported it made camping in 2°F weather “very bearable,” keeping their 8’x8′ tent comparatively warm overnight on the low setting. The sheer heat output on the high setting is something you have to feel to believe; it truly lives up to its ‘Big Buddy’ name. We found this model to be one of the most powerful in its class.

The three-tier heating system is the key to its versatility.

• Low (4,000 BTU): This setting uses only one heating panel and sips propane. It’s perfect for smaller spaces like a truck camper, an ice fishing shack, or for maintaining the temperature in a larger space once it’s already warmed up.
• Medium (9,000 BTU): This also uses one panel but at a higher output. We found this to be the sweet spot for taking the edge off in our garage without running at full blast, providing a good balance of heat and fuel efficiency.
• High (18,000 BTU): This engages both ceramic panels for maximum power. This is the setting you’ll use to rapidly heat a large, cold space. It consumes fuel more quickly, but its ability to transform a frigid area into a comfortable one is undeniable.

Safety First: The Triple-Threat Protection System

When you’re using a propane-fueled appliance indoors, you can’t compromise on safety. This is where the Mr. Heater Big Buddy PRO Series 18,000 BTU Heater truly shines and gives us the confidence to recommend it. It incorporates three critical, automatic safety features. The first is the tip-over switch. During our testing, we gave the heater a firm nudge—enough to knock it off balance—and it shut down instantly and completely. The click was audible, and the flame was extinguished before the unit even fully settled on its side. This provides immense peace of mind, especially in a busy workshop or a tent with kids or pets.

The second, and arguably most important, feature for indoor use is the Oxygen Depletion Sensor (ODS). This device constantly monitors the oxygen levels in the surrounding air. If the levels fall below a predetermined safe threshold, the ODS automatically shuts the heater off completely. While we always advocate for cracking a window or providing some form of ventilation as per the manufacturer’s instructions, the ODS acts as a silent, vigilant guardian against the potential for a dangerous, low-oxygen environment. The third safety feature is the thermocouple, which shuts off the gas if the pilot light ever goes out, preventing raw propane from leaking into your space. These integrated safety features are non-negotiable for us, making the Mr. Heater Big Buddy a top contender for indoor use and a product we feel comfortable operating for extended periods.

Fuel Flexibility and Real-World Usability

Versatility is a core strength of the Big Buddy. The ability to screw in two 1 lb propane canisters makes it incredibly portable for camping, fishing, or tailgating. However, for stationary use in a garage or as an emergency home heater, connecting it to a 20 lb propane tank is far more economical. We used the official Mr. Heater hose (model F273704) and filter for this purpose. A crucial tip we picked up from seasoned users is the importance of the filter to prevent oily plasticizers from the hose from clogging the heater’s internal components over time. Another invaluable piece of advice is the shutdown procedure: always turn the valve off at the 20 lb tank first, let the heater burn off the remaining gas in the line until it extinguishes, and then turn the heater’s control knob to “Off.” This depressurizes the hose and regulator, which users claim significantly extends the life of the seals.

The ignition process does have a learning curve, as some reviews point out. It’s not a simple turn-and-click. You must press and hold the control knob in the “Pilot” position for 30-60 seconds to purge the air and allow the gas to reach the thermocouple. Once the pilot is lit, you continue to hold the knob for another 30 seconds before turning to your desired heat setting. Once we learned this “process,” as one user aptly called it, ignition was reliable every single time. It’s a minor inconvenience born from its safety-first design. We also noted the confusion around the igniter itself. While advertised as a Piezo system, our unit—and that of at least one other user—required a single AAA battery in a hidden compartment to power the sparker. This is a critical detail to be aware of upon purchase.

What Other Users Are Saying

Across the board, user sentiment for the Mr. Heater Big Buddy PRO Series 18,000 BTU Heater is overwhelmingly positive, focusing on its exceptional heat output. One user, who uses it in a Quonset hut in the Pacific Northwest, called it and its smaller sibling a source of “perfectly warm” conditions during a 15-degree cold snap. Another confirmed its value for emergency preparedness and its ability to run flawlessly on high with just a single 20 lb tank connected to one side.

However, the feedback isn’t without its criticisms, which largely align with our own findings. Several users received units with initial defects, such as a faulty thermocouple or a broken latch on the side doors, requiring an exchange or a call to customer support. On that note, one user who had an issue had a very positive experience, stating, “Contacted product support and they sent me two parts to replace. When replaced, this works like a charm. Very happy with support. Quick to respond.” The built-in fan is another point of contention. While a nice feature, most agree it’s underpowered. As one user bluntly put it, after buying the official AC adapter, “don’t waste your money on the adapter it doesn’t work most of the time and it falls out, buy a cheap adapter.” This mix of powerful performance combined with occasional quality control and design quirks paints a realistic picture of the product. Despite some minor quibbles, the overwhelming consensus points to a highly effective heater. You can read through hundreds of similar experiences here.

How Does the Mr. Heater Big Buddy Compare to the Alternatives?

The Mr. Heater Big Buddy PRO Series 18,000 BTU Heater exists in a competitive market. While it excels in portable propane heating, different needs may call for a different solution. Here’s how it stacks up against three notable alternatives.

1. DR. INFRARED HEATER DR-238 Outdoor Heater

The DR. INFRARED HEATER DR-238 is an electric, wall- or ceiling-mounted infrared heater. The most significant difference is the power source. This model is for someone who needs a permanent or semi-permanent heating solution for a covered patio, garage, or restaurant setting where an electrical outlet is readily available. It produces clean, silent, odorless heat instantly, much like the sun’s rays. While powerful for an electric model, its output is significantly lower than the Big Buddy’s max setting. It completely lacks portability and is useless during a power outage. Choose the Dr. Infrared heater if you value plug-and-play convenience and have a fixed location you want to heat consistently without dealing with propane tanks.

2. Heat Hog 18,000 BTU Portable Propane Heater

The Heat Hog is a direct competitor to the Big Buddy, offering the same 18,000 BTU maximum output and running on propane. Its standout feature is its rugged, tiltable design. This allows the user to direct the radiant heat upwards at an angle, which can be particularly useful for staying warm while standing at a workbench or for thawing equipment on a job site. It’s built with a more industrial aesthetic and may appeal to contractors or those who need a more directional heat source. The choice between the Heat Hog and the Big Buddy comes down to form factor preference: the stable, forward-facing heat of the Big Buddy versus the rugged, adjustable-angle design of the Heat Hog.

3. Briza 1500W Infrared Patio Heater

The Briza Infrared heater is another electric alternative, similar to the Dr. Infrared but with a focus on portability and versatility in mounting. It can be mounted on a wall, ceiling, or used with a portable tripod stand. At 1500W, its heat output is equivalent to about 5,100 BTUs, which is comparable to the Big Buddy’s low setting. This makes it suitable for providing targeted warmth to a small, specific area, like a seating arrangement on a patio or a desk space in a cold room. It’s not designed to heat large, enclosed spaces like the Big Buddy can. Someone who wants the safety and simplicity of electricity for a smaller zone and values the option of a stand for portability would prefer the Briza.

Our Final Verdict: Is the Mr. Heater Big Buddy Worth It?

After extensive testing and analysis, our conclusion is a resounding yes. The Mr. Heater Big Buddy PRO Series 18,000 BTU Heater is a phenomenal piece of gear that delivers on its promise of powerful, portable, and safe heat. It is the definitive solution for anyone needing to warm up a garage, workshop, large tent, or for those seeking a reliable emergency heat source during a power outage. Its immense 18,000 BTU output can tame seriously cold spaces, while its lower settings provide efficient, long-lasting warmth. The comprehensive safety features, particularly the ODS and tip-over switch, provide the essential peace of mind needed for indoor operation.

While it’s not perfect—the ignition has a learning curve, the fan is underwhelming, and some units may have initial quality control issues—its core performance is so strong that these points become minor footnotes. It is a versatile, robust, and incredibly effective tool. If you need serious, portable heat that you can rely on when the temperature plummets, we wholeheartedly recommend you check out the Mr. Heater Big Buddy PRO Series 18,000 BTU Heater today.