Mr. Heater Heater Review: Buddy vs Big Buddy vs Little Buddy

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Mr. Heater Buddy heaters dominate the portable propane heater market. We have no relationship with Mr. Heater; we’re just presenting a fact.

And that’s the reason behind this Mr. Heater Buddy Heaters Review. When you’ve finished this Mr. Heater review, we hope you’ll know:

  • The models available
  • Their specifications (specs), sizes, similarities and differences
  • Their cost ranges
  • Which model or models will best serve your purposes

What Mr. Heater Buddy Models Have in Common

Before we review the individual models, here is what you get from all of them.

Indoor/Outdoor Use – Oxygen Depletion Sensor

This is an exciting feature of the Mr. Heater portable propane heaters. They are safe for indoor use.

The ODS, or oxygen depletion sensor does just what the name implies. If it senses the oxygen level in the area is lower than it should be, the sensor will signal the heater to turn Off. It will do this before the O2 level gets dangerously low.

Mr. Buddy recommends using a little ventilation in enclosed/indoor settings to ensure a supply of fresh air for you to breathe and for propane combustion.

Push-Button Lighting

Mr. Heater Buddy heaters are easy to light using the Piezo sparking mechanism. Turn on the propane, and push the Piezo button. Read the directions or watch the setup videos we’ve included with each review.

Pro Tip: It might take a while if you’re starting the heater for the first time out of the box or the first time a new bottle/tank is used.

  • 1lb bottle: It might take a few seconds for propane to flow through the heaters gas valve and into the combustion chamber.
  • 20lb tank and hose: Expect it to take up to 3 minutes the first time it is connected. Try the Piezo lighter every 15-20 seconds, and it will soon fire up. If you smell gas before you’ve sparked it, turn off the gas and give it a few minutes to disperse. Turn on the gas and click, and you should get heat.

Tip-over Protection

This protection is common to all gas and electric space heaters. The specific method varies, but if the unit is tipped past about 45 degrees, combustion will stop immediately.

Mr. Heater recommends that you check the tip-over protection by holding the heater and tilting it past 45 degrees (in other words, don’t just push it over).

1-Year Warranty

If there’s anything we’re not thrilled with on Mr. Heater Buddy heaters, it’s the short warranty. To be fair:

A 1-year warranty is the industry average and better than the warranties offered on some portable gas heaters.

Mr. Heater Buddy heaters are 3-season workhorses for a lot of use – fishing, camping, working in the garage, finishing a building project, getting an early start or extending the season on the deck and elsewhere. Take care of your Buddy, and you can expect years of dependable heating.

Mr. Heater Buddy Heater Reviews

This summary table allows you to compare Mr. Heater Buddy models at a glance.

Model Size / Settings Location Bottles * Room Size Run Time
Litte Buddy 3,800 BTU Indoor/Outdoor 1lb 95 sq. ft.  5.6 Hours
Buddy 4,000 & 9,000 BTU Indoor/Outdoor 1lb or 20 – 40lb 225 sq. ft.  3/6 Hours
Big Buddy 4K, 9K & 18K BTU Indoor/Outdoor Two 1lb or 20 – 40lb 450 sq. ft.  3/6/12 Hours

Here are reviews for the three sizes.

#1 Mr. Heater Little Buddy Portable Propane Heater Review

This is a popular “personal size” propane space heater. It heats an enclosed space up to 95 square feet, or a little short of 10×10.

If you use it outside, then you’ll have to huddle pretty close to it to feel its heat. This is especially true if there is more than one of you that want some of those 3,800 BTUs.

Setup: The 1lb propane bottle screws into the heating head. The bottle sits in the base. This 3-minute video explains setup and use.


  1. Indoor/Outdoor
  2. 3,800 BTUs / 95 square feet enclosed space.
  3. Adjustable heating head.
  4. Radiant heat – No fan.
  5. Piezo starter.
  6. ODS – oxygen depletion sensor with shut-off.
  7. Tip-over protection.
  8. Current model # (subject to change) Mr. Heater MH4B

User Reviews:

  • Top positive review: “Used it late winter camping in Michigan’s UP. Outside temps were 25 to 35 at night. Raised our 4-person tent 55-62 degrees. Plenty warm.”
  • Top negative review: “Takes a good hour to get a small fishing shanty reasonably warm. When I set up the shanty, the inside temp was 35F. After one hour: 42 degrees. After 2-hours: 55 degrees. A larger size is prolly a better option for freezing weather applications.”

Best Use: Small tent, hunting blind or fishing shanty. It’s also very nice for use on a workbench in the garage or basement to keep hands warm while working on a project.

Where you shouldn’t use it: It isn’t recommended for moving vehicles such as a car or golf cart. Mr. Heater does make a Little Buddy version for Golf Carts. It basically fits in a cup holder, so could be used elsewhere too.

#2 Mr. Heater Buddy Portable Propane Heater Review

This is the medium size and the best seller. Depending on how insulated the space is, it will keep a small space very warm or a medium (20×12) space adequately warm.

It’s also large enough for outdoor use in chilly weather, as long as you stay fairly near it.

Setup: Make sure the Gas Knob in the Off position. Swing out the gas nozzle, and thread the 1lb bottle onto it. Hold the Piezo ignition until the pilot comes on. When it lights, test the tip-over shut off.

The heater can be used with 20lb/30lb/40lb tanks using a Mr. Heater hose. A fuel filter is required for some hoses. The proper hose and filter combinations are explained in the Mr. Heater video on the product page link.

The hose screws into the heater and attaches to the tank. Remember, it will take a while for the propane to flow through 12 feet of hose.

Pro Tip: Save the seals! Propane deteriorates seals over time. For this reason, we recommend unscrewing the bottle when not in use. If you’re connected to a tank, then turn off the propane on the tank, and let the heater go out. This will clear the line of propane and improve the durability of the seal.

Mr. Heater makes a handy carrying case too.


  1. Indoor/Outdoor
  2. Use with 1lb bottles or 20-40lb tanks.
  3. 2 settings: 4,000 and 9,000 BTUs / Up to 225 square feet enclosed space.
  4. Off/Low/High knob.
  5. Fold-down carrying handle.
  6. Radiant heat – No fan.
  7. Piezo starter.
  8. ODS – oxygen depletion sensor with shut-off.
  9. Tip-over protection.
  10. Current model # (subject to change) Mr. Heater MH9BX

User Reviews:

  • Top positive review: “Very dependable heater for 5+ years of regular use. I recommend using a 20lb or larger tank instead of the bottle for economy and so you don’t have to change tanks as often on extended us when camping/hunting.”
  • Top negative review: “Caused our carbon monoxide detector in the cabin to go off, even with one window open. We had to open a window across from it to get cross breeze. No more issues.”

Best Use: Medium-sized tent, fishing shanty or hunting blind. It is large enough to heat a camper 16-22 feet or a 1-car garage if it isn’t sub-zero outside. Of course, it depends how much of a heat boost you want over outside temperatures. See the table at the end of the post for information on this topic.

Where you shouldn’t use it: It has an open flame, so we do not recommend using it where animals or kids could burn themselves. It’s a poor choice where straw bedding for horses, etc., could catch fire.

#3 ​Mr. Heater Big Buddy Portable Propane Heater Review

This is the largest and most versatile size. It’s three settings heat up to 95/225/450 square feet. The Big Buddy runs off one or two 1lb bottles or a larger tank and hose.

The Big Buddy also has a fan that can be powered by 4 “D” batteries or an AC adapter that sells separately. It is the only model of the three with this feature.

Setup: Make sure the Gas Knob in the Off position. Swing out one or both gas nozzles, and thread on the bottle(s). Hold the Piezo ignition until the pilot comes on. Mr. Heater recommends testing the tip-over shut-off by holding the heater and tipping it more than 45 degrees to ensure the burner shuts down.

The heater can be used with 20lb to 40lb tanks using a Mr. Heater hose.

The hose screws into the heater and attaches to the tank. Remember, it will take a while for the propane to flow through 12 feet of hose.

This is the proper Hose/Regulator combination for this model.

This is the 6V adapter, a very useful accessory when you have access to a 110V outlet.

Pro Tip: The Mr. Buddy adapter is OK, but they have a higher fail rate than they should. We recommend this compatible model by PWR. It works exactly the same but with better dependability, has a 2-year warranty instead of 1, and it costs less.


  1. Indoor/Outdoor
  2. Use with one or two 1lb bottles or 20-40lb tanks.
  3. Swivel-out regulators for bottles or hose.
  4. 3 settings: 4,000, 9,000 & 18,000 BTUs / Up to 450 square feet enclosed space.
  5. Off/Low/Medium/High knob.
  6. Fan powered by 4 “D” batteries of 6V adapter.
  7. Can be used without the fan for radiant-heat only.
  8. Fixed carrying handle.
  9. Piezo starter.
  10. ODS – oxygen depletion sensor with shut-off.
  11. Tip-over protection.
  12. Current model #s (subject to change) Mr. Heater MH18B and MH18BRV

User Reviews:

  • Top positive review: “I replaced two oil-filled space heaters in the garage with the Big Buddy by Mr Heater. Two benefits: Much better heating in my 2-car garage when it is freezing outside (literally). It’s much more comfortable when I’m working on the car. Secondly, I’m spending less on heating when I use a 30lb propane tank. Propane heat is more affordable than electric heat.”
  • Top negative review: “I get 8-10 hours out of batteries, and they’re not cheap. If you have power, definitely use the adapter. And the fan has only on/off options – not low/high.”

Best Use: Large/Family tent, fishing shanty or hunting blind. It is large enough to heat a camper 18-28 feet or a 2-car garage, depending on insulation, outside temp and how much of a heat boost you want.

Where you shouldn’t use it: Because of the heat setting options, you can use it anywhere. However, we don’t recommend the 18,000 BTU setting for insulated space less than 250 square feet. Not only will you probably be too warm, this setting is likely to trigger a low-oxygen shut-off. Of course, don’t use any propane heater too close to flammable materials. See the User Guide or Product Page for spacing.

Which Mr. Heater Buddy Heater is Right for You?

How much do you want to raise the temperature? How big is the space you’re heating? What kind of space is it?

This table gives a general answer to these two important questions. It should help you decide which model is best. In truth, because these portable propane space heaters are so affordable and dependable, many people have two or three to match the heater to the specific need.

Model Max. Rating Raise 20F Raise 40F Raise 40F (Insulated)
Little Buddy 95 sq. ft. 70-100 sq. ft. 50-75 sq. ft. 80-120 sq. ft.
Buddy 225 sq. ft. 200-250 sq. ft. 160-215 sq. ft. 200-275 sq. ft.
Big Buddy 450 sq. ft. 390-475 sq. ft. 360-425 sq. ft. 400-550 sq. ft.

Raise 20F / Raise 40F: These are semi-insulated or poorly insulated locations like a tent, non-insulated shanty or blind.

Raise 40F Insulated: These are decently insulated locations like an RV, cabin, shanty or blind or garage with some insulation.

The ranges vary because conditions vary so much.

Written by

Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. He holds an HVAC associate degree from Lone Star College and EPA & R-410A Certifications.

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