Mr. Heater makes two quite different kinds of portable propane heater, and the difference matters more than the BTU number. The Buddy family is listed for indoor and outdoor use, for spaces like a tent, ice shack or workshop. The tank-top, cabinet, convection and forced-air heaters are listed for outdoor use or open work areas only. This guide sorts the models we carry by where you will use them, then covers the hoses, filter and fuel.
If you are still deciding between propane, diesel and electric heat for your rig, start with our comparison of diesel heaters vs propane furnaces vs electric heat for RVs.
Start with where the heater will run
Before comparing output, decide where the heat is needed. The listings split the range into two groups:
- Indoor/outdoor (the Buddy heaters). The Little Buddy MH4B and Big Buddy MH18B listings say "rated for indoor and outdoor use." The Portable Buddy F232000 and Buddy FLEX MH11BFLEX listings describe them as indoor-safe with low-oxygen and tip-over shut-off.
- Outdoor only. The Single Tank Top MHS15T, Double Tank Top MHS30T, Tank Top MH540T and Cabinet Heater MH18CH listings each say "for outdoor use only." The Convection Heater MH80CVX listing says it is rated for outdoor use.
- Jobsite. The Forced Air Heater MHC60FAV listing says it is a jobsite-style heater for a work area or shop and "not for use inside an RV living space."
An indoor rating does not remove the basic rules for burning propane in an enclosed space. Every Buddy listing says propane appliances need ventilation and to follow the manual, and the Little Buddy and Big Buddy listings add: keep a working CO detector nearby. If you plan to use any heater inside a camper, tent or shop, crack a window or vent as the manual describes, keep the heater clear of bedding, curtains and anything else that can burn, and put a CO detector where you sleep. We stock CO and propane detectors.
Mr. Heater models compared
| Model | Output as listed | Use as listed | Fuel or connection |
|---|---|---|---|
| Little Buddy MH4B | 3,800 BTU | Indoor and outdoor | Propane; check the cylinder it takes |
| Portable Buddy F232000 | 4,000 or 9,000 BTU | Indoor-safe per listing | 1 lb cylinder, swivel regulator |
| Buddy FLEX MH11BFLEX | Up to 11,000 BTU | Indoor-safe per listing | 1 lb cylinders |
| Big Buddy MH18B | Up to 18,000 BTU | Indoor and outdoor | Two 1 lb cylinders, or a 20 lb tank with hose |
| Single Tank Top MHS15T | 15,000 BTU | Outdoor only | Sits on a propane tank (not included) |
| Double Tank Top MHS30T | 30,000 BTU | Outdoor only | Mounts on a propane tank (not included) |
| Tank Top MH540T | Up to 45,000 BTU | Outdoor only | Mounts on a propane tank (not included) |
| Cabinet Heater MH18CH | 18,000 BTU | Outdoor only | Hose and regulator included, tank not included |
| Convection Heater MH80CVX | 80,000 high / 30,000 low BTU | Outdoor use | Propane |
| Forced Air Heater MHC60FAV | 60,000 BTU | Work area or shop, not an RV living space | 10 ft hose and regulator included |
The Buddy heaters: tent, camper and small spaces
Little Buddy
The Little Buddy MH4B is the smallest heater here at 3,800 BTU of radiant heat. The listing suggests it for taking the chill off a tent, a small workspace or a campsite seat on a cool morning.
Portable Buddy and Buddy FLEX
The Portable Buddy F232000 has two settings, 4,000 or 9,000 BTU, and the listing says it heats up to about 200 sq ft. It runs on a 1 lb propane cylinder with a swivel regulator and has a fold-down handle. The Buddy FLEX MH11BFLEX is described as the newer, more adjustable member of the family, with heat up to 11,000 BTU and a burner that spreads heat across 180°. Mr. Heater lists a Life Safety System with low-oxygen and tip-over shut-off on the FLEX. Pick the FLEX if you want finer control and a wider spread.
Big Buddy
The Big Buddy MH18B is the larger Buddy, rated up to 18,000 BTU, for campers, cabins and cold-weather camping. The listing says it runs on two 1 lb cylinders or on a 20 lb tank with a hose sold separately, and that it has swivel regulators.
Outdoor heaters: campsite, tailgate and work area
- Tank-top radiant. These sit on a propane tank. The Single Tank Top MHS15T has a single radiant head, the Double Tank Top MHS30T has two heads and a listed heating area of up to 750 sq. ft., and the Tank Top MH540T puts out up to 45,000 BTU with 540° radiant heat for warming a group around the campsite.
- Cabinet. The Cabinet Heater MH18CH is an 18,000 BTU cabinet heater with hose and regulator included, for a campsite, patio or open work area.
- Convection. The Convection Heater MH80CVX has a cylindrical chamber that sends heat in all directions, with high and low settings of 80,000 and 30,000 BTU. The listing says it heats up to 2,000 sq ft.
- Forced air. The Forced Air Heater MHC60FAV is a contractor-series torpedo heater. The listing suggests it for a cold garage while you work on the rig, not for the living space.
The outdoor listings all say to keep clear space around the heater, keep it away from tents, awnings and anything that can burn, and not to leave it running unattended.
Hoses, filter and fuel
To run a heater from a larger tank or cut down on disposable bottles, these parts help. Each listing says to confirm fittings and leak-check connections:
- Buddy Propane Hose Assembly F273704: 10 ft, made for Mr. Heater Buddy heaters, for running the heater from a larger tank.
- Big Buddy 12 ft Hose with Regulator F271803: 12 ft with a regulator and solid brass quick-connect fittings. The listing says it connects a Big Buddy to your RV's regulated propane line and that no fuel filter is required with this hose. Confirm the connection on your rig against the heater manual before using it.
- Universal Propane Fuel Filter F273699: a universal in-line filter that installs in the supply line ahead of a heater, a common add-on when running from a larger tank through a hose.
- 12 ft Hose & Regulator Assembly: 12 ft, connects low-pressure portable appliances to a 20 lb cylinder and handles up to 75,000 BTU. That covers the Buddy heaters, but not the 80,000 BTU setting of the convection heater.
- 12 ft Propane Extension Hose F298902: adds distance between the tank and the appliance so the tank can sit out of the way.
- Fuel Keg: a refillable 16 oz cylinder that replaces disposable 1 lb bottles. It ships empty, so plan how you will fill it before your trip.
For regulators, fittings and other propane parts, see our propane and gas parts or the Flame King range.
How to choose
- Decide indoor or outdoor first. If the heater will ever run inside a tent, camper or shop, stay with the Buddy family and follow the manual for ventilation.
- Match output to the space. The Little Buddy suits a seat or small tent; the Portable Buddy and FLEX suit a small space; the Big Buddy is for a larger camper or cabin. Outdoors, step up to a tank-top or cabinet heater for a group.
- Plan the fuel. Run time depends on the heat setting and cylinder size, so check the manual. If you want longer stretches between changes, look at a hose to a larger tank or a Fuel Keg.
- Check the connection. Confirm your heater model, tank fitting and hose before you order, and leak-check with soapy water before lighting.
- Add a CO detector for any indoor use.
See the full range on our Mr. Heater page, and ask us with your model number if you are unsure which hose fits.