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Heaters for Ice Shelters: Portable Buddy vs Big Buddy

Short answer: The Mr. Heater Portable Buddy (up to 9,000 BTU, rated to 225 sq ft) covers flip-overs and 1–3 person hubs. The Big Buddy (up to 18,000 BTU, rated to 450 sq ft) suits 4–5 person hubs and small shacks. Vent the shelter and carry a CO alarm with either.

A propane radiant heater is standard gear in nearly every hub and flip-over. The Mr. Heater Buddy line is the one you'll see most. Below is how to size one and how to run it without getting hurt.

Spec comparison

	Portable Buddy (MH9BX)	Big Buddy (MH18B)
Output	4,000 / 9,000 BTU/hr	4,000 / 9,000 / 18,000 BTU/hr
Rated heating area	Up to 225 sq ft	Up to 450 sq ft
Fuel	One 1-lb cylinder (20-lb tank with optional hose & filter)	One or two 1-lb cylinders (20-lb tank with optional hose)
Run time (manual)	3–6 hr on a 1-lb cylinder; 48–110 hr on 20 lb	1.5–6 hr on one 1-lb; 3–12 hr on two; 50–220 hr on two 20-lb
Weight	10.6 lb	17.1 lb
Safety	Oxygen depletion sensor (ODS), tip-over shut-off	ODS, tip-over shut-off
Clearance to combustibles	Top 30", front 24", sides 6"	Top 30", front 24", sides 6"
Max elevation	7,000 ft	7,000 ft

Sources: mrheater.com product pages and owner's manuals for MH9BX and MH18B (Oct 2026). Mr. Heater notes that run times "can be significantly reduced" below 20°F with small cylinders, and recommends a 20-lb tank in those conditions. Massachusetts/Canada versions differ, so buy the right one for where you live.

Sizing to your shelter

• Flip-overs and 1–3 person hubs (roughly 16–64 sq ft): the Portable Buddy is plenty. Most of the day it'll run on low.
• 4–5 person hubs like a 75 sq ft Outbreak, or a small permanent shack: the Big Buddy gives you headroom on a -20°F, windy day.

Running it safely

• Follow the manual's ventilation guidance. Crack vents even with the ODS, and carry a battery CO alarm in the shelter.
• Keep fabric walls, sleeping bags and jackets outside the clearance distances above.
• Small 1-lb cylinders lose pressure in deep cold. Keep spares inside your coat or run a 20-lb tank with the proper hose and filter.

Quick questions

Is it safe to run a propane heater in an ice shelter?

Both Buddy heaters have an oxygen depletion sensor and tip-over shut-off, but you still need to follow the manual's ventilation guidance, crack vents, and carry a battery CO alarm.

Why does my 1-lb propane cylinder die fast in the cold?

Mr. Heater says run times can be significantly reduced below 20°F with small cylinders and recommends a 20-lb tank with the proper hose and filter in those conditions.

Gear in this guide

• Where to buy the Mr. Heater Portable Buddy (MH9BX) · more on Mr. Heater
• Where to buy the Mr. Heater Big Buddy (MH18B) · more on Mr. Heater

Related guides

• Insulated Hub Shelters: Eskimo Outbreak 450XDP vs Clam X-400 Thermal
• Flip-Over Fish Houses: Clam Legend XT Thermal vs Eskimo Sierra Thermal
• Hub vs Flip-Over Shelters: How to Choose (Round 2)
• How to Set Up a Hub Shelter on the Ice (and Take It Down)

Written by Cory Arnold, Iron County, Michigan. Specs checked October 2026.

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